Merge branch 'kvm-6.11-sev-snp' into HEAD

Pull base x86 KVM support for running SEV-SNP guests from Michael Roth:

* add some basic infrastructure and introduces a new KVM_X86_SNP_VM
  vm_type to handle differences versus the existing KVM_X86_SEV_VM and
  KVM_X86_SEV_ES_VM types.

* implement the KVM API to handle the creation of a cryptographic
  launch context, encrypt/measure the initial image into guest memory,
  and finalize it before launching it.

* implement handling for various guest-generated events such as page
  state changes, onlining of additional vCPUs, etc.

* implement the gmem/mmu hooks needed to prepare gmem-allocated pages
  before mapping them into guest private memory ranges as well as
  cleaning them up prior to returning them to the host for use as
  normal memory. Because those cleanup hooks supplant certain
  activities like issuing WBINVDs during KVM MMU invalidations, avoid
  duplicating that work to avoid unecessary overhead.

This merge leaves out support support for attestation guest requests
and for loading the signing keys to be used for attestation requests.

21 files changed, 1917 insertions, 51 deletions

diff --git a/Documentation/virt/kvm/x86/amd-memory-encryption.rst b/Documentation/virt/kvm/x86/amd-memory-encryption.rst
index 9677a0714a39..1ddb6a86ce7f 100644
--- a/Documentation/virt/kvm/x86/amd-memory-encryption.rst
+++ b/Documentation/virt/kvm/x86/amd-memory-encryption.rst
@@ -466,6 +466,112 @@ issued by the hypervisor to make the guest ready for execution.
 
 Returns: 0 on success, -negative on error
 
+18. KVM_SEV_SNP_LAUNCH_START
+----------------------------
+
+The KVM_SNP_LAUNCH_START command is used for creating the memory encryption
+context for the SEV-SNP guest. It must be called prior to issuing
+KVM_SEV_SNP_LAUNCH_UPDATE or KVM_SEV_SNP_LAUNCH_FINISH;
+
+Parameters (in): struct  kvm_sev_snp_launch_start
+
+Returns: 0 on success, -negative on error
+
+::
+
+        struct kvm_sev_snp_launch_start {
+                __u64 policy;           /* Guest policy to use. */
+                __u8 gosvw[16];         /* Guest OS visible workarounds. */
+                __u16 flags;            /* Must be zero. */
+                __u8 pad0[6];
+                __u64 pad1[4];
+        };
+
+See SNP_LAUNCH_START in the SEV-SNP specification [snp-fw-abi]_ for further
+details on the input parameters in ``struct kvm_sev_snp_launch_start``.
+
+19. KVM_SEV_SNP_LAUNCH_UPDATE
+-----------------------------
+
+The KVM_SEV_SNP_LAUNCH_UPDATE command is used for loading userspace-provided
+data into a guest GPA range, measuring the contents into the SNP guest context
+created by KVM_SEV_SNP_LAUNCH_START, and then encrypting/validating that GPA
+range so that it will be immediately readable using the encryption key
+associated with the guest context once it is booted, after which point it can
+attest the measurement associated with its context before unlocking any
+secrets.
+
+It is required that the GPA ranges initialized by this command have had the
+KVM_MEMORY_ATTRIBUTE_PRIVATE attribute set in advance. See the documentation
+for KVM_SET_MEMORY_ATTRIBUTES for more details on this aspect.
+
+Upon success, this command is not guaranteed to have processed the entire
+range requested. Instead, the ``gfn_start``, ``uaddr``, and ``len`` fields of
+``struct kvm_sev_snp_launch_update`` will be updated to correspond to the
+remaining range that has yet to be processed. The caller should continue
+calling this command until those fields indicate the entire range has been
+processed, e.g. ``len`` is 0, ``gfn_start`` is equal to the last GFN in the
+range plus 1, and ``uaddr`` is the last byte of the userspace-provided source
+buffer address plus 1. In the case where ``type`` is KVM_SEV_SNP_PAGE_TYPE_ZERO,
+``uaddr`` will be ignored completely.
+
+Parameters (in): struct  kvm_sev_snp_launch_update
+
+Returns: 0 on success, < 0 on error, -EAGAIN if caller should retry
+
+::
+
+        struct kvm_sev_snp_launch_update {
+                __u64 gfn_start;        /* Guest page number to load/encrypt data into. */
+                __u64 uaddr;            /* Userspace address of data to be loaded/encrypted. */
+                __u64 len;              /* 4k-aligned length in bytes to copy into guest memory.*/
+                __u8 type;              /* The type of the guest pages being initialized. */
+                __u8 pad0;
+                __u16 flags;            /* Must be zero. */
+                __u32 pad1;
+                __u64 pad2[4];
+
+        };
+
+where the allowed values for page_type are #define'd as::
+
+        KVM_SEV_SNP_PAGE_TYPE_NORMAL
+        KVM_SEV_SNP_PAGE_TYPE_ZERO
+        KVM_SEV_SNP_PAGE_TYPE_UNMEASURED
+        KVM_SEV_SNP_PAGE_TYPE_SECRETS
+        KVM_SEV_SNP_PAGE_TYPE_CPUID
+
+See the SEV-SNP spec [snp-fw-abi]_ for further details on how each page type is
+used/measured.
+
+20. KVM_SEV_SNP_LAUNCH_FINISH
+-----------------------------
+
+After completion of the SNP guest launch flow, the KVM_SEV_SNP_LAUNCH_FINISH
+command can be issued to make the guest ready for execution.
+
+Parameters (in): struct kvm_sev_snp_launch_finish
+
+Returns: 0 on success, -negative on error
+
+::
+
+        struct kvm_sev_snp_launch_finish {
+                __u64 id_block_uaddr;
+                __u64 id_auth_uaddr;
+                __u8 id_block_en;
+                __u8 auth_key_en;
+                __u8 vcek_disabled;
+                __u8 host_data[32];
+                __u8 pad0[3];
+                __u16 flags;                    /* Must be zero */
+                __u64 pad1[4];
+        };
+
+
+See SNP_LAUNCH_FINISH in the SEV-SNP specification [snp-fw-abi]_ for further
+details on the input parameters in ``struct kvm_sev_snp_launch_finish``.
+
 Device attribute API
 ====================
 
@@ -497,9 +603,11 @@ References
 ==========
 
 
-See [white-paper]_, [api-spec]_, [amd-apm]_ and [kvm-forum]_ for more info.
+See [white-paper]_, [api-spec]_, [amd-apm]_, [kvm-forum]_, and [snp-fw-abi]_
+for more info.
 
 .. [white-paper] https://developer.amd.com/wordpress/media/2013/12/AMD_Memory_Encryption_Whitepaper_v7-Public.pdf
 .. [api-spec] https://support.amd.com/TechDocs/55766_SEV-KM_API_Specification.pdf
 .. [amd-apm] https://support.amd.com/TechDocs/24593.pdf (section 15.34)
 .. [kvm-forum]  https://www.linux-kvm.org/images/7/74/02x08A-Thomas_Lendacky-AMDs_Virtualizatoin_Memory_Encryption_Technology.pdf
+.. [snp-fw-abi] https://www.amd.com/system/files/TechDocs/56860.pdf
diff --git a/arch/x86/include/asm/kvm-x86-ops.h b/arch/x86/include/asm/kvm-x86-ops.h
index 5187fcf4b610..566d19b02483 100644
--- a/arch/x86/include/asm/kvm-x86-ops.h
+++ b/arch/x86/include/asm/kvm-x86-ops.h
@@ -139,6 +139,9 @@ KVM_X86_OP(vcpu_deliver_sipi_vector)
 KVM_X86_OP_OPTIONAL_RET0(vcpu_get_apicv_inhibit_reasons);
 KVM_X86_OP_OPTIONAL(get_untagged_addr)
 KVM_X86_OP_OPTIONAL(alloc_apic_backing_page)
+KVM_X86_OP_OPTIONAL_RET0(gmem_prepare)
+KVM_X86_OP_OPTIONAL_RET0(private_max_mapping_level)
+KVM_X86_OP_OPTIONAL(gmem_invalidate)
 
 #undef KVM_X86_OP
 #undef KVM_X86_OP_OPTIONAL
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index f8ca74e7678f..9bb2e164c523 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -121,6 +121,7 @@
 	KVM_ARCH_REQ_FLAGS(31, KVM_REQUEST_WAIT | KVM_REQUEST_NO_WAKEUP)
 #define KVM_REQ_HV_TLB_FLUSH \
 	KVM_ARCH_REQ_FLAGS(32, KVM_REQUEST_WAIT | KVM_REQUEST_NO_WAKEUP)
+#define KVM_REQ_UPDATE_PROTECTED_GUEST_STATE	KVM_ARCH_REQ(34)
 
 #define CR0_RESERVED_BITS                                               \
 	(~(unsigned long)(X86_CR0_PE | X86_CR0_MP | X86_CR0_EM | X86_CR0_TS \
@@ -1812,6 +1813,9 @@ struct kvm_x86_ops {
 
 	gva_t (*get_untagged_addr)(struct kvm_vcpu *vcpu, gva_t gva, unsigned int flags);
 	void *(*alloc_apic_backing_page)(struct kvm_vcpu *vcpu);
+	int (*gmem_prepare)(struct kvm *kvm, kvm_pfn_t pfn, gfn_t gfn, int max_order);
+	void (*gmem_invalidate)(kvm_pfn_t start, kvm_pfn_t end);
+	int (*private_max_mapping_level)(struct kvm *kvm, kvm_pfn_t pfn);
 };
 
 struct kvm_x86_nested_ops {
@@ -1939,6 +1943,7 @@ void kvm_mmu_slot_leaf_clear_dirty(struct kvm *kvm,
 				   const struct kvm_memory_slot *memslot);
 void kvm_mmu_invalidate_mmio_sptes(struct kvm *kvm, u64 gen);
 void kvm_mmu_change_mmu_pages(struct kvm *kvm, unsigned long kvm_nr_mmu_pages);
+void kvm_zap_gfn_range(struct kvm *kvm, gfn_t gfn_start, gfn_t gfn_end);
 
 int load_pdptrs(struct kvm_vcpu *vcpu, unsigned long cr3);
 
diff --git a/arch/x86/include/asm/sev-common.h b/arch/x86/include/asm/sev-common.h
index 5a8246dd532f..8647cc05e2f4 100644
--- a/arch/x86/include/asm/sev-common.h
+++ b/arch/x86/include/asm/sev-common.h
@@ -59,6 +59,14 @@
 #define GHCB_MSR_AP_RESET_HOLD_RESULT_POS	12
 #define GHCB_MSR_AP_RESET_HOLD_RESULT_MASK	GENMASK_ULL(51, 0)
 
+/* Preferred GHCB GPA Request */
+#define GHCB_MSR_PREF_GPA_REQ		0x010
+#define GHCB_MSR_GPA_VALUE_POS		12
+#define GHCB_MSR_GPA_VALUE_MASK		GENMASK_ULL(51, 0)
+
+#define GHCB_MSR_PREF_GPA_RESP		0x011
+#define GHCB_MSR_PREF_GPA_NONE		0xfffffffffffff
+
 /* GHCB GPA Register */
 #define GHCB_MSR_REG_GPA_REQ		0x012
 #define GHCB_MSR_REG_GPA_REQ_VAL(v)			\
@@ -93,11 +101,17 @@ enum psc_op {
 	/* GHCBData[11:0] */				\
 	GHCB_MSR_PSC_REQ)
 
+#define GHCB_MSR_PSC_REQ_TO_GFN(msr) (((msr) & GENMASK_ULL(51, 12)) >> 12)
+#define GHCB_MSR_PSC_REQ_TO_OP(msr) (((msr) & GENMASK_ULL(55, 52)) >> 52)
+
 #define GHCB_MSR_PSC_RESP		0x015
 #define GHCB_MSR_PSC_RESP_VAL(val)			\
 	/* GHCBData[63:32] */				\
 	(((u64)(val) & GENMASK_ULL(63, 32)) >> 32)
 
+/* Set highest bit as a generic error response */
+#define GHCB_MSR_PSC_RESP_ERROR (BIT_ULL(63) | GHCB_MSR_PSC_RESP)
+
 /* GHCB Hypervisor Feature Request/Response */
 #define GHCB_MSR_HV_FT_REQ		0x080
 #define GHCB_MSR_HV_FT_RESP		0x081
@@ -115,8 +129,19 @@ enum psc_op {
  *   The VMGEXIT_PSC_MAX_ENTRY determines the size of the PSC structure, which
  *   is a local stack variable in set_pages_state(). Do not increase this value
  *   without evaluating the impact to stack usage.
+ *
+ *   Use VMGEXIT_PSC_MAX_COUNT in cases where the actual GHCB-defined max value
+ *   is needed, such as when processing GHCB requests on the hypervisor side.
  */
 #define VMGEXIT_PSC_MAX_ENTRY		64
+#define VMGEXIT_PSC_MAX_COUNT		253
+
+#define VMGEXIT_PSC_ERROR_GENERIC	(0x100UL << 32)
+#define VMGEXIT_PSC_ERROR_INVALID_HDR	((1UL << 32) | 1)
+#define VMGEXIT_PSC_ERROR_INVALID_ENTRY	((1UL << 32) | 2)
+
+#define VMGEXIT_PSC_OP_PRIVATE		1
+#define VMGEXIT_PSC_OP_SHARED		2
 
 struct psc_hdr {
 	u16 cur_entry;
diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h
index ca20cc4e5826..1936f37e3371 100644
--- a/arch/x86/include/asm/sev.h
+++ b/arch/x86/include/asm/sev.h
@@ -91,6 +91,9 @@ extern bool handle_vc_boot_ghcb(struct pt_regs *regs);
 /* RMUPDATE detected 4K page and 2MB page overlap. */
 #define RMPUPDATE_FAIL_OVERLAP		4
 
+/* PSMASH failed due to concurrent access by another CPU */
+#define PSMASH_FAIL_INUSE		3
+
 /* RMP page size */
 #define RMP_PG_SIZE_4K			0
 #define RMP_PG_SIZE_2M			1
diff --git a/arch/x86/include/asm/svm.h b/arch/x86/include/asm/svm.h
index 728c98175b9c..f0dea3750ca9 100644
--- a/arch/x86/include/asm/svm.h
+++ b/arch/x86/include/asm/svm.h
@@ -285,7 +285,14 @@ static_assert((X2AVIC_MAX_PHYSICAL_ID & AVIC_PHYSICAL_MAX_INDEX_MASK) == X2AVIC_
 
 #define AVIC_HPA_MASK	~((0xFFFULL << 52) | 0xFFF)
 
-#define SVM_SEV_FEAT_DEBUG_SWAP                        BIT(5)
+#define SVM_SEV_FEAT_SNP_ACTIVE				BIT(0)
+#define SVM_SEV_FEAT_RESTRICTED_INJECTION		BIT(3)
+#define SVM_SEV_FEAT_ALTERNATE_INJECTION		BIT(4)
+#define SVM_SEV_FEAT_DEBUG_SWAP				BIT(5)
+
+#define SVM_SEV_FEAT_INT_INJ_MODES		\
+	(SVM_SEV_FEAT_RESTRICTED_INJECTION |	\
+	 SVM_SEV_FEAT_ALTERNATE_INJECTION)
 
 struct vmcb_seg {
 	u16 selector;
diff --git a/arch/x86/include/uapi/asm/kvm.h b/arch/x86/include/uapi/asm/kvm.h
index 9fae1b73b529..988b5204d636 100644
--- a/arch/x86/include/uapi/asm/kvm.h
+++ b/arch/x86/include/uapi/asm/kvm.h
@@ -697,6 +697,11 @@ enum sev_cmd_id {
 	/* Second time is the charm; improved versions of the above ioctls.  */
 	KVM_SEV_INIT2,
 
+	/* SNP-specific commands */
+	KVM_SEV_SNP_LAUNCH_START = 100,
+	KVM_SEV_SNP_LAUNCH_UPDATE,
+	KVM_SEV_SNP_LAUNCH_FINISH,
+
 	KVM_SEV_NR_MAX,
 };
 
@@ -824,6 +829,48 @@ struct kvm_sev_receive_update_data {
 	__u32 pad2;
 };
 
+struct kvm_sev_snp_launch_start {
+	__u64 policy;
+	__u8 gosvw[16];
+	__u16 flags;
+	__u8 pad0[6];
+	__u64 pad1[4];
+};
+
+/* Kept in sync with firmware values for simplicity. */
+#define KVM_SEV_SNP_PAGE_TYPE_NORMAL		0x1
+#define KVM_SEV_SNP_PAGE_TYPE_ZERO		0x3
+#define KVM_SEV_SNP_PAGE_TYPE_UNMEASURED	0x4
+#define KVM_SEV_SNP_PAGE_TYPE_SECRETS		0x5
+#define KVM_SEV_SNP_PAGE_TYPE_CPUID		0x6
+
+struct kvm_sev_snp_launch_update {
+	__u64 gfn_start;
+	__u64 uaddr;
+	__u64 len;
+	__u8 type;
+	__u8 pad0;
+	__u16 flags;
+	__u32 pad1;
+	__u64 pad2[4];
+};
+
+#define KVM_SEV_SNP_ID_BLOCK_SIZE	96
+#define KVM_SEV_SNP_ID_AUTH_SIZE	4096
+#define KVM_SEV_SNP_FINISH_DATA_SIZE	32
+
+struct kvm_sev_snp_launch_finish {
+	__u64 id_block_uaddr;
+	__u64 id_auth_uaddr;
+	__u8 id_block_en;
+	__u8 auth_key_en;
+	__u8 vcek_disabled;
+	__u8 host_data[KVM_SEV_SNP_FINISH_DATA_SIZE];
+	__u8 pad0[3];
+	__u16 flags;
+	__u64 pad1[4];
+};
+
 #define KVM_X2APIC_API_USE_32BIT_IDS            (1ULL << 0)
 #define KVM_X2APIC_API_DISABLE_BROADCAST_QUIRK  (1ULL << 1)
 
@@ -874,5 +921,6 @@ struct kvm_hyperv_eventfd {
 #define KVM_X86_SW_PROTECTED_VM	1
 #define KVM_X86_SEV_VM		2
 #define KVM_X86_SEV_ES_VM	3
+#define KVM_X86_SNP_VM		4
 
 #endif /* _ASM_X86_KVM_H */
diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig
index fec95a770270..80e5afde69f4 100644
--- a/arch/x86/kvm/Kconfig
+++ b/arch/x86/kvm/Kconfig
@@ -139,6 +139,9 @@ config KVM_AMD_SEV
 	depends on KVM_AMD && X86_64
 	depends on CRYPTO_DEV_SP_PSP && !(KVM_AMD=y && CRYPTO_DEV_CCP_DD=m)
 	select ARCH_HAS_CC_PLATFORM
+	select KVM_GENERIC_PRIVATE_MEM
+	select HAVE_KVM_GMEM_PREPARE
+	select HAVE_KVM_GMEM_INVALIDATE
 	help
 	  Provides support for launching Encrypted VMs (SEV) and Encrypted VMs
 	  with Encrypted State (SEV-ES) on AMD processors.
diff --git a/arch/x86/kvm/mmu.h b/arch/x86/kvm/mmu.h
index 2e454316f2a2..dc80e72e4848 100644
--- a/arch/x86/kvm/mmu.h
+++ b/arch/x86/kvm/mmu.h
@@ -253,8 +253,6 @@ static inline bool kvm_mmu_honors_guest_mtrrs(struct kvm *kvm)
 	return __kvm_mmu_honors_guest_mtrrs(kvm_arch_has_noncoherent_dma(kvm));
 }
 
-void kvm_zap_gfn_range(struct kvm *kvm, gfn_t gfn_start, gfn_t gfn_end);
-
 int kvm_arch_write_log_dirty(struct kvm_vcpu *vcpu);
 
 int kvm_mmu_post_init_vm(struct kvm *kvm);
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index b7b4426a7221..f2c9580d9588 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -3308,7 +3308,7 @@ static int kvm_handle_noslot_fault(struct kvm_vcpu *vcpu,
 	return RET_PF_CONTINUE;
 }
 
-static bool page_fault_can_be_fast(struct kvm_page_fault *fault)
+static bool page_fault_can_be_fast(struct kvm *kvm, struct kvm_page_fault *fault)
 {
 	/*
 	 * Page faults with reserved bits set, i.e. faults on MMIO SPTEs, only
@@ -3320,6 +3320,26 @@ static bool page_fault_can_be_fast(struct kvm_page_fault *fault)
 		return false;
 
 	/*
+	 * For hardware-protected VMs, certain conditions like attempting to
+	 * perform a write to a page which is not in the state that the guest
+	 * expects it to be in can result in a nested/extended #PF. In this
+	 * case, the below code might misconstrue this situation as being the
+	 * result of a write-protected access, and treat it as a spurious case
+	 * rather than taking any action to satisfy the real source of the #PF
+	 * such as generating a KVM_EXIT_MEMORY_FAULT. This can lead to the
+	 * guest spinning on a #PF indefinitely, so don't attempt the fast path
+	 * in this case.
+	 *
+	 * Note that the kvm_mem_is_private() check might race with an
+	 * attribute update, but this will either result in the guest spinning
+	 * on RET_PF_SPURIOUS until the update completes, or an actual spurious
+	 * case might go down the slow path. Either case will resolve itself.
+	 */
+	if (kvm->arch.has_private_mem &&
+	    fault->is_private != kvm_mem_is_private(kvm, fault->gfn))
+		return false;
+
+	/*
 	 * #PF can be fast if:
 	 *
 	 * 1. The shadow page table entry is not present and A/D bits are
@@ -3419,7 +3439,7 @@ static int fast_page_fault(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault)
 	u64 *sptep;
 	uint retry_count = 0;
 
-	if (!page_fault_can_be_fast(fault))
+	if (!page_fault_can_be_fast(vcpu->kvm, fault))
 		return ret;
 
 	walk_shadow_page_lockless_begin(vcpu);
@@ -4291,6 +4311,25 @@ static inline u8 kvm_max_level_for_order(int order)
 	return PG_LEVEL_4K;
 }
 
+static u8 kvm_max_private_mapping_level(struct kvm *kvm, kvm_pfn_t pfn,
+					u8 max_level, int gmem_order)
+{
+	u8 req_max_level;
+
+	if (max_level == PG_LEVEL_4K)
+		return PG_LEVEL_4K;
+
+	max_level = min(kvm_max_level_for_order(gmem_order), max_level);
+	if (max_level == PG_LEVEL_4K)
+		return PG_LEVEL_4K;
+
+	req_max_level = static_call(kvm_x86_private_max_mapping_level)(kvm, pfn);
+	if (req_max_level)
+		max_level = min(max_level, req_max_level);
+
+	return req_max_level;
+}
+
 static int kvm_faultin_pfn_private(struct kvm_vcpu *vcpu,
 				   struct kvm_page_fault *fault)
 {
@@ -4308,9 +4347,9 @@ static int kvm_faultin_pfn_private(struct kvm_vcpu *vcpu,
 		return r;
 	}
 
-	fault->max_level = min(kvm_max_level_for_order(max_order),
-			       fault->max_level);
 	fault->map_writable = !(fault->slot->flags & KVM_MEM_READONLY);
+	fault->max_level = kvm_max_private_mapping_level(vcpu->kvm, fault->pfn,
+							 fault->max_level, max_order);
 
 	return RET_PF_CONTINUE;
 }
@@ -6790,6 +6829,7 @@ restart:
 
 	return need_tlb_flush;
 }
+EXPORT_SYMBOL_GPL(kvm_zap_gfn_range);
 
 static void kvm_rmap_zap_collapsible_sptes(struct kvm *kvm,
 					   const struct kvm_memory_slot *slot)
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 95095a233a45..113243daa3d6 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -25,6 +25,7 @@
 #include <asm/fpu/xcr.h>
 #include <asm/fpu/xstate.h>
 #include <asm/debugreg.h>
+#include <asm/sev.h>
 
 #include "mmu.h"
 #include "x86.h"
@@ -37,7 +38,7 @@
 #define GHCB_VERSION_DEFAULT	2ULL
 #define GHCB_VERSION_MIN	1ULL
 
-#define GHCB_HV_FT_SUPPORTED	GHCB_HV_FT_SNP
+#define GHCB_HV_FT_SUPPORTED	(GHCB_HV_FT_SNP | GHCB_HV_FT_SNP_AP_CREATION)
 
 /* enable/disable SEV support */
 static bool sev_enabled = true;
@@ -47,6 +48,10 @@ module_param_named(sev, sev_enabled, bool, 0444);
 static bool sev_es_enabled = true;
 module_param_named(sev_es, sev_es_enabled, bool, 0444);
 
+/* enable/disable SEV-SNP support */
+static bool sev_snp_enabled = true;
+module_param_named(sev_snp, sev_snp_enabled, bool, 0444);
+
 /* enable/disable SEV-ES DebugSwap support */
 static bool sev_es_debug_swap_enabled = true;
 module_param_named(debug_swap, sev_es_debug_swap_enabled, bool, 0444);
@@ -56,6 +61,23 @@ static u64 sev_supported_vmsa_features;
 #define AP_RESET_HOLD_NAE_EVENT		1
 #define AP_RESET_HOLD_MSR_PROTO		2
 
+/* As defined by SEV-SNP Firmware ABI, under "Guest Policy". */
+#define SNP_POLICY_MASK_API_MINOR	GENMASK_ULL(7, 0)
+#define SNP_POLICY_MASK_API_MAJOR	GENMASK_ULL(15, 8)
+#define SNP_POLICY_MASK_SMT		BIT_ULL(16)
+#define SNP_POLICY_MASK_RSVD_MBO	BIT_ULL(17)
+#define SNP_POLICY_MASK_DEBUG		BIT_ULL(19)
+#define SNP_POLICY_MASK_SINGLE_SOCKET	BIT_ULL(20)
+
+#define SNP_POLICY_MASK_VALID		(SNP_POLICY_MASK_API_MINOR	| \
+					 SNP_POLICY_MASK_API_MAJOR	| \
+					 SNP_POLICY_MASK_SMT		| \
+					 SNP_POLICY_MASK_RSVD_MBO	| \
+					 SNP_POLICY_MASK_DEBUG		| \
+					 SNP_POLICY_MASK_SINGLE_SOCKET)
+
+#define INITIAL_VMSA_GPA 0xFFFFFFFFF000
+
 static u8 sev_enc_bit;
 static DECLARE_RWSEM(sev_deactivate_lock);
 static DEFINE_MUTEX(sev_bitmap_lock);
@@ -66,6 +88,8 @@ static unsigned int nr_asids;
 static unsigned long *sev_asid_bitmap;
 static unsigned long *sev_reclaim_asid_bitmap;
 
+static int snp_decommission_context(struct kvm *kvm);
+
 struct enc_region {
 	struct list_head list;
 	unsigned long npages;
@@ -92,12 +116,17 @@ static int sev_flush_asids(unsigned int min_asid, unsigned int max_asid)
 	down_write(&sev_deactivate_lock);
 
 	wbinvd_on_all_cpus();
-	ret = sev_guest_df_flush(&error);
+
+	if (sev_snp_enabled)
+		ret = sev_do_cmd(SEV_CMD_SNP_DF_FLUSH, NULL, &error);
+	else
+		ret = sev_guest_df_flush(&error);
 
 	up_write(&sev_deactivate_lock);
 
 	if (ret)
-		pr_err("SEV: DF_FLUSH failed, ret=%d, error=%#x\n", ret, error);
+		pr_err("SEV%s: DF_FLUSH failed, ret=%d, error=%#x\n",
+		       sev_snp_enabled ? "-SNP" : "", ret, error);
 
 	return ret;
 }
@@ -233,6 +262,53 @@ static void sev_decommission(unsigned int handle)
 	sev_guest_decommission(&decommission, NULL);
 }
 
+/*
+ * Transition a page to hypervisor-owned/shared state in the RMP table. This
+ * should not fail under normal conditions, but leak the page should that
+ * happen since it will no longer be usable by the host due to RMP protections.
+ */
+static int kvm_rmp_make_shared(struct kvm *kvm, u64 pfn, enum pg_level level)
+{
+	if (KVM_BUG_ON(rmp_make_shared(pfn, level), kvm)) {
+		snp_leak_pages(pfn, page_level_size(level) >> PAGE_SHIFT);
+		return -EIO;
+	}
+
+	return 0;
+}
+
+/*
+ * Certain page-states, such as Pre-Guest and Firmware pages (as documented
+ * in Chapter 5 of the SEV-SNP Firmware ABI under "Page States") cannot be
+ * directly transitioned back to normal/hypervisor-owned state via RMPUPDATE
+ * unless they are reclaimed first.
+ *
+ * Until they are reclaimed and subsequently transitioned via RMPUPDATE, they
+ * might not be usable by the host due to being set as immutable or still
+ * being associated with a guest ASID.
+ *
+ * Bug the VM and leak the page if reclaim fails, or if the RMP entry can't be
+ * converted back to shared, as the page is no longer usable due to RMP
+ * protections, and it's infeasible for the guest to continue on.
+ */
+static int snp_page_reclaim(struct kvm *kvm, u64 pfn)
+{
+	struct sev_data_snp_page_reclaim data = {0};
+	int fw_err, rc;
+
+	data.paddr = __sme_set(pfn << PAGE_SHIFT);
+	rc = sev_do_cmd(SEV_CMD_SNP_PAGE_RECLAIM, &data, &fw_err);
+	if (KVM_BUG(rc, kvm, "Failed to reclaim PFN %llx, rc %d fw_err %d", pfn, rc, fw_err)) {
+		snp_leak_pages(pfn, 1);
+		return -EIO;
+	}
+
+	if (kvm_rmp_make_shared(kvm, pfn, PG_LEVEL_4K))
+		return -EIO;
+
+	return rc;
+}
+
 static void sev_unbind_asid(struct kvm *kvm, unsigned int handle)
 {
 	struct sev_data_deactivate deactivate;
@@ -288,6 +364,9 @@ static int __sev_guest_init(struct kvm *kvm, struct kvm_sev_cmd *argp,
 	if (sev->es_active && !sev->ghcb_version)
 		sev->ghcb_version = GHCB_VERSION_DEFAULT;
 
+	if (vm_type == KVM_X86_SNP_VM)
+		sev->vmsa_features |= SVM_SEV_FEAT_SNP_ACTIVE;
+
 	ret = sev_asid_new(sev);
 	if (ret)
 		goto e_no_asid;
@@ -348,7 +427,8 @@ static int sev_guest_init2(struct kvm *kvm, struct kvm_sev_cmd *argp)
 		return -EINVAL;
 
 	if (kvm->arch.vm_type != KVM_X86_SEV_VM &&
-	    kvm->arch.vm_type != KVM_X86_SEV_ES_VM)
+	    kvm->arch.vm_type != KVM_X86_SEV_ES_VM &&
+	    kvm->arch.vm_type != KVM_X86_SNP_VM)
 		return -EINVAL;
 
 	if (copy_from_user(&data, u64_to_user_ptr(argp->data), sizeof(data)))
@@ -1999,6 +2079,402 @@ int sev_dev_get_attr(u32 group, u64 attr, u64 *val)
 	}
 }
 
+/*
+ * The guest context contains all the information, keys and metadata
+ * associated with the guest that the firmware tracks to implement SEV
+ * and SNP features. The firmware stores the guest context in hypervisor
+ * provide page via the SNP_GCTX_CREATE command.
+ */
+static void *snp_context_create(struct kvm *kvm, struct kvm_sev_cmd *argp)
+{
+	struct sev_data_snp_addr data = {};
+	void *context;
+	int rc;
+
+	/* Allocate memory for context page */
+	context = snp_alloc_firmware_page(GFP_KERNEL_ACCOUNT);
+	if (!context)
+		return NULL;
+
+	data.address = __psp_pa(context);
+	rc = __sev_issue_cmd(argp->sev_fd, SEV_CMD_SNP_GCTX_CREATE, &data, &argp->error);
+	if (rc) {
+		pr_warn("Failed to create SEV-SNP context, rc %d fw_error %d",
+			rc, argp->error);
+		snp_free_firmware_page(context);
+		return NULL;
+	}
+
+	return context;
+}
+
+static int snp_bind_asid(struct kvm *kvm, int *error)
+{
+	struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
+	struct sev_data_snp_activate data = {0};
+
+	data.gctx_paddr = __psp_pa(sev->snp_context);
+	data.asid = sev_get_asid(kvm);
+	return sev_issue_cmd(kvm, SEV_CMD_SNP_ACTIVATE, &data, error);
+}
+
+static int snp_launch_start(struct kvm *kvm, struct kvm_sev_cmd *argp)
+{
+	struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
+	struct sev_data_snp_launch_start start = {0};
+	struct kvm_sev_snp_launch_start params;
+	int rc;
+
+	if (!sev_snp_guest(kvm))
+		return -ENOTTY;
+
+	if (copy_from_user(&params, u64_to_user_ptr(argp->data), sizeof(params)))
+		return -EFAULT;
+
+	/* Don't allow userspace to allocate memory for more than 1 SNP context. */
+	if (sev->snp_context)
+		return -EINVAL;
+
+	sev->snp_context = snp_context_create(kvm, argp);
+	if (!sev->snp_context)
+		return -ENOTTY;
+
+	if (params.flags)
+		return -EINVAL;
+
+	if (params.policy & ~SNP_POLICY_MASK_VALID)
+		return -EINVAL;
+
+	/* Check for policy bits that must be set */
+	if (!(params.policy & SNP_POLICY_MASK_RSVD_MBO) ||
+	    !(params.policy & SNP_POLICY_MASK_SMT))
+		return -EINVAL;
+
+	if (params.policy & SNP_POLICY_MASK_SINGLE_SOCKET)
+		return -EINVAL;
+
+	start.gctx_paddr = __psp_pa(sev->snp_context);
+	start.policy = params.policy;
+	memcpy(start.gosvw, params.gosvw, sizeof(params.gosvw));
+	rc = __sev_issue_cmd(argp->sev_fd, SEV_CMD_SNP_LAUNCH_START, &start, &argp->error);
+	if (rc) {
+		pr_debug("%s: SEV_CMD_SNP_LAUNCH_START firmware command failed, rc %d\n",
+			 __func__, rc);
+		goto e_free_context;
+	}
+
+	sev->fd = argp->sev_fd;
+	rc = snp_bind_asid(kvm, &argp->error);
+	if (rc) {
+		pr_debug("%s: Failed to bind ASID to SEV-SNP context, rc %d\n",
+			 __func__, rc);
+		goto e_free_context;
+	}
+
+	return 0;
+
+e_free_context:
+	snp_decommission_context(kvm);
+
+	return rc;
+}
+
+struct sev_gmem_populate_args {
+	__u8 type;
+	int sev_fd;
+	int fw_error;
+};
+
+static int sev_gmem_post_populate(struct kvm *kvm, gfn_t gfn_start, kvm_pfn_t pfn,
+				  void __user *src, int order, void *opaque)
+{
+	struct sev_gmem_populate_args *sev_populate_args = opaque;
+	struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
+	int n_private = 0, ret, i;
+	int npages = (1 << order);
+	gfn_t gfn;
+
+	if (WARN_ON_ONCE(sev_populate_args->type != KVM_SEV_SNP_PAGE_TYPE_ZERO && !src))
+		return -EINVAL;
+
+	for (gfn = gfn_start, i = 0; gfn < gfn_start + npages; gfn++, i++) {
+		struct sev_data_snp_launch_update fw_args = {0};
+		bool assigned;
+		int level;
+
+		if (!kvm_mem_is_private(kvm, gfn)) {
+			pr_debug("%s: Failed to ensure GFN 0x%llx has private memory attribute set\n",
+				 __func__, gfn);
+			ret = -EINVAL;
+			goto err;
+		}
+
+		ret = snp_lookup_rmpentry((u64)pfn + i, &assigned, &level);
+		if (ret || assigned) {
+			pr_debug("%s: Failed to ensure GFN 0x%llx RMP entry is initial shared state, ret: %d assigned: %d\n",
+				 __func__, gfn, ret, assigned);
+			ret = -EINVAL;
+			goto err;
+		}
+
+		if (src) {
+			void *vaddr = kmap_local_pfn(pfn + i);
+
+			ret = copy_from_user(vaddr, src + i * PAGE_SIZE, PAGE_SIZE);
+			if (ret)
+				goto err;
+			kunmap_local(vaddr);
+		}
+
+		ret = rmp_make_private(pfn + i, gfn << PAGE_SHIFT, PG_LEVEL_4K,
+				       sev_get_asid(kvm), true);
+		if (ret)
+			goto err;
+
+		n_private++;
+
+		fw_args.gctx_paddr = __psp_pa(sev->snp_context);
+		fw_args.address = __sme_set(pfn_to_hpa(pfn + i));
+		fw_args.page_size = PG_LEVEL_TO_RMP(PG_LEVEL_4K);
+		fw_args.page_type = sev_populate_args->type;
+
+		ret = __sev_issue_cmd(sev_populate_args->sev_fd, SEV_CMD_SNP_LAUNCH_UPDATE,
+				      &fw_args, &sev_populate_args->fw_error);
+		if (ret)
+			goto fw_err;
+	}
+
+	return 0;
+
+fw_err:
+	/*
+	 * If the firmware command failed handle the reclaim and cleanup of that
+	 * PFN specially vs. prior pages which can be cleaned up below without
+	 * needing to reclaim in advance.
+	 *
+	 * Additionally, when invalid CPUID function entries are detected,
+	 * firmware writes the expected values into the page and leaves it
+	 * unencrypted so it can be used for debugging and error-reporting.
+	 *
+	 * Copy this page back into the source buffer so userspace can use this
+	 * information to provide information on which CPUID leaves/fields
+	 * failed CPUID validation.
+	 */
+	if (!snp_page_reclaim(kvm, pfn + i) &&
+	    sev_populate_args->type == KVM_SEV_SNP_PAGE_TYPE_CPUID &&
+	    sev_populate_args->fw_error == SEV_RET_INVALID_PARAM) {
+		void *vaddr = kmap_local_pfn(pfn + i);
+
+		if (copy_to_user(src + i * PAGE_SIZE, vaddr, PAGE_SIZE))
+			pr_debug("Failed to write CPUID page back to userspace\n");
+
+		kunmap_local(vaddr);
+	}
+
+	/* pfn + i is hypervisor-owned now, so skip below cleanup for it. */
+	n_private--;
+
+err:
+	pr_debug("%s: exiting with error ret %d (fw_error %d), restoring %d gmem PFNs to shared.\n",
+		 __func__, ret, sev_populate_args->fw_error, n_private);
+	for (i = 0; i < n_private; i++)
+		kvm_rmp_make_shared(kvm, pfn + i, PG_LEVEL_4K);
+
+	return ret;
+}
+
+static int snp_launch_update(struct kvm *kvm, struct kvm_sev_cmd *argp)
+{
+	struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
+	struct sev_gmem_populate_args sev_populate_args = {0};
+	struct kvm_sev_snp_launch_update params;
+	struct kvm_memory_slot *memslot;
+	long npages, count;
+	void __user *src;
+	int ret = 0;
+
+	if (!sev_snp_guest(kvm) || !sev->snp_context)
+		return -EINVAL;
+
+	if (copy_from_user(&params, u64_to_user_ptr(argp->data), sizeof(params)))
+		return -EFAULT;
+
+	pr_debug("%s: GFN start 0x%llx length 0x%llx type %d flags %d\n", __func__,
+		 params.gfn_start, params.len, params.type, params.flags);
+
+	if (!PAGE_ALIGNED(params.len) || params.flags ||
+	    (params.type != KVM_SEV_SNP_PAGE_TYPE_NORMAL &&
+	     params.type != KVM_SEV_SNP_PAGE_TYPE_ZERO &&
+	     params.type != KVM_SEV_SNP_PAGE_TYPE_UNMEASURED &&
+	     params.type != KVM_SEV_SNP_PAGE_TYPE_SECRETS &&
+	     params.type != KVM_SEV_SNP_PAGE_TYPE_CPUID))
+		return -EINVAL;
+
+	npages = params.len / PAGE_SIZE;
+
+	/*
+	 * For each GFN that's being prepared as part of the initial guest
+	 * state, the following pre-conditions are verified:
+	 *
+	 *   1) The backing memslot is a valid private memslot.
+	 *   2) The GFN has been set to private via KVM_SET_MEMORY_ATTRIBUTES
+	 *      beforehand.
+	 *   3) The PFN of the guest_memfd has not already been set to private
+	 *      in the RMP table.
+	 *
+	 * The KVM MMU relies on kvm->mmu_invalidate_seq to retry nested page
+	 * faults if there's a race between a fault and an attribute update via
+	 * KVM_SET_MEMORY_ATTRIBUTES, and a similar approach could be utilized
+	 * here. However, kvm->slots_lock guards against both this as well as
+	 * concurrent memslot updates occurring while these checks are being
+	 * performed, so use that here to make it easier to reason about the
+	 * initial expected state and better guard against unexpected
+	 * situations.
+	 */
+	mutex_lock(&kvm->slots_lock);
+
+	memslot = gfn_to_memslot(kvm, params.gfn_start);
+	if (!kvm_slot_can_be_private(memslot)) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	sev_populate_args.sev_fd = argp->sev_fd;
+	sev_populate_args.type = params.type;
+	src = params.type == KVM_SEV_SNP_PAGE_TYPE_ZERO ? NULL : u64_to_user_ptr(params.uaddr);
+
+	count = kvm_gmem_populate(kvm, params.gfn_start, src, npages,
+				  sev_gmem_post_populate, &sev_populate_args);
+	if (count < 0) {
+		argp->error = sev_populate_args.fw_error;
+		pr_debug("%s: kvm_gmem_populate failed, ret %ld (fw_error %d)\n",
+			 __func__, count, argp->error);
+		ret = -EIO;
+	} else {
+		params.gfn_start += count;
+		params.len -= count * PAGE_SIZE;
+		if (params.type != KVM_SEV_SNP_PAGE_TYPE_ZERO)
+			params.uaddr += count * PAGE_SIZE;
+
+		ret = 0;
+		if (copy_to_user(u64_to_user_ptr(argp->data), &params, sizeof(params)))
+			ret = -EFAULT;
+	}
+
+out:
+	mutex_unlock(&kvm->slots_lock);
+
+	return ret;
+}
+
+static int snp_launch_update_vmsa(struct kvm *kvm, struct kvm_sev_cmd *argp)
+{
+	struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
+	struct sev_data_snp_launch_update data = {};
+	struct kvm_vcpu *vcpu;
+	unsigned long i;
+	int ret;
+
+	data.gctx_paddr = __psp_pa(sev->snp_context);
+	data.page_type = SNP_PAGE_TYPE_VMSA;
+
+	kvm_for_each_vcpu(i, vcpu, kvm) {
+		struct vcpu_svm *svm = to_svm(vcpu);
+		u64 pfn = __pa(svm->sev_es.vmsa) >> PAGE_SHIFT;
+
+		ret = sev_es_sync_vmsa(svm);
+		if (ret)
+			return ret;
+
+		/* Transition the VMSA page to a firmware state. */
+		ret = rmp_make_private(pfn, INITIAL_VMSA_GPA, PG_LEVEL_4K, sev->asid, true);
+		if (ret)
+			return ret;
+
+		/* Issue the SNP command to encrypt the VMSA */
+		data.address = __sme_pa(svm->sev_es.vmsa);
+		ret = __sev_issue_cmd(argp->sev_fd, SEV_CMD_SNP_LAUNCH_UPDATE,
+				      &data, &argp->error);
+		if (ret) {
+			snp_page_reclaim(kvm, pfn);
+
+			return ret;
+		}
+
+		svm->vcpu.arch.guest_state_protected = true;
+	}
+
+	return 0;
+}
+
+static int snp_launch_finish(struct kvm *kvm, struct kvm_sev_cmd *argp)
+{
+	struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
+	struct kvm_sev_snp_launch_finish params;
+	struct sev_data_snp_launch_finish *data;
+	void *id_block = NULL, *id_auth = NULL;
+	int ret;
+
+	if (!sev_snp_guest(kvm))
+		return -ENOTTY;
+
+	if (!sev->snp_context)
+		return -EINVAL;
+
+	if (copy_from_user(&params, u64_to_user_ptr(argp->data), sizeof(params)))
+		return -EFAULT;
+
+	if (params.flags)
+		return -EINVAL;
+
+	/* Measure all vCPUs using LAUNCH_UPDATE before finalizing the launch flow. */
+	ret = snp_launch_update_vmsa(kvm, argp);
+	if (ret)
+		return ret;
+
+	data = kzalloc(sizeof(*data), GFP_KERNEL_ACCOUNT);
+	if (!data)
+		return -ENOMEM;
+
+	if (params.id_block_en) {
+		id_block = psp_copy_user_blob(params.id_block_uaddr, KVM_SEV_SNP_ID_BLOCK_SIZE);
+		if (IS_ERR(id_block)) {
+			ret = PTR_ERR(id_block);
+			goto e_free;
+		}
+
+		data->id_block_en = 1;
+		data->id_block_paddr = __sme_pa(id_block);
+
+		id_auth = psp_copy_user_blob(params.id_auth_uaddr, KVM_SEV_SNP_ID_AUTH_SIZE);
+		if (IS_ERR(id_auth)) {
+			ret = PTR_ERR(id_auth);
+			goto e_free_id_block;
+		}
+
+		data->id_auth_paddr = __sme_pa(id_auth);
+
+		if (params.auth_key_en)
+			data->auth_key_en = 1;
+	}
+
+	data->vcek_disabled = params.vcek_disabled;
+
+	memcpy(data->host_data, params.host_data, KVM_SEV_SNP_FINISH_DATA_SIZE);
+	data->gctx_paddr = __psp_pa(sev->snp_context);
+	ret = sev_issue_cmd(kvm, SEV_CMD_SNP_LAUNCH_FINISH, data, &argp->error);
+
+	kfree(id_auth);
+
+e_free_id_block:
+	kfree(id_block);
+
+e_free:
+	kfree(data);
+
+	return ret;
+}
+
 int sev_mem_enc_ioctl(struct kvm *kvm, void __user *argp)
 {
 	struct kvm_sev_cmd sev_cmd;
@@ -2022,6 +2498,15 @@ int sev_mem_enc_ioctl(struct kvm *kvm, void __user *argp)
 		goto out;
 	}
 
+	/*
+	 * Once KVM_SEV_INIT2 initializes a KVM instance as an SNP guest, only
+	 * allow the use of SNP-specific commands.
+	 */
+	if (sev_snp_guest(kvm) && sev_cmd.id < KVM_SEV_SNP_LAUNCH_START) {
+		r = -EPERM;
+		goto out;
+	}
+
 	switch (sev_cmd.id) {
 	case KVM_SEV_ES_INIT:
 		if (!sev_es_enabled) {
@@ -2086,6 +2571,15 @@ int sev_mem_enc_ioctl(struct kvm *kvm, void __user *argp)
 	case KVM_SEV_RECEIVE_FINISH:
 		r = sev_receive_finish(kvm, &sev_cmd);
 		break;
+	case KVM_SEV_SNP_LAUNCH_START:
+		r = snp_launch_start(kvm, &sev_cmd);
+		break;
+	case KVM_SEV_SNP_LAUNCH_UPDATE:
+		r = snp_launch_update(kvm, &sev_cmd);
+		break;
+	case KVM_SEV_SNP_LAUNCH_FINISH:
+		r = snp_launch_finish(kvm, &sev_cmd);
+		break;
 	default:
 		r = -EINVAL;
 		goto out;
@@ -2281,6 +2775,31 @@ e_source_fput:
 	return ret;
 }
 
+static int snp_decommission_context(struct kvm *kvm)
+{
+	struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
+	struct sev_data_snp_addr data = {};
+	int ret;
+
+	/* If context is not created then do nothing */
+	if (!sev->snp_context)
+		return 0;
+
+	/* Do the decommision, which will unbind the ASID from the SNP context */
+	data.address = __sme_pa(sev->snp_context);
+	down_write(&sev_deactivate_lock);
+	ret = sev_do_cmd(SEV_CMD_SNP_DECOMMISSION, &data, NULL);
+	up_write(&sev_deactivate_lock);
+
+	if (WARN_ONCE(ret, "Failed to release guest context, ret %d", ret))
+		return ret;
+
+	snp_free_firmware_page(sev->snp_context);
+	sev->snp_context = NULL;
+
+	return 0;
+}
+
 void sev_vm_destroy(struct kvm *kvm)
 {
 	struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
@@ -2322,7 +2841,17 @@ void sev_vm_destroy(struct kvm *kvm)
 		}
 	}
 
-	sev_unbind_asid(kvm, sev->handle);
+	if (sev_snp_guest(kvm)) {
+		/*
+		 * Decomission handles unbinding of the ASID. If it fails for
+		 * some unexpected reason, just leak the ASID.
+		 */
+		if (snp_decommission_context(kvm))
+			return;
+	} else {
+		sev_unbind_asid(kvm, sev->handle);
+	}
+
 	sev_asid_free(sev);
 }
 
@@ -2336,11 +2865,16 @@ void __init sev_set_cpu_caps(void)
 		kvm_cpu_cap_set(X86_FEATURE_SEV_ES);
 		kvm_caps.supported_vm_types |= BIT(KVM_X86_SEV_ES_VM);
 	}
+	if (sev_snp_enabled) {
+		kvm_cpu_cap_set(X86_FEATURE_SEV_SNP);
+		kvm_caps.supported_vm_types |= BIT(KVM_X86_SNP_VM);
+	}
 }
 
 void __init sev_hardware_setup(void)
 {
 	unsigned int eax, ebx, ecx, edx, sev_asid_count, sev_es_asid_count;
+	bool sev_snp_supported = false;
 	bool sev_es_supported = false;
 	bool sev_supported = false;
 
@@ -2427,6 +2961,7 @@ void __init sev_hardware_setup(void)
 	sev_es_asid_count = min_sev_asid - 1;
 	WARN_ON_ONCE(misc_cg_set_capacity(MISC_CG_RES_SEV_ES, sev_es_asid_count));
 	sev_es_supported = true;
+	sev_snp_supported = sev_snp_enabled && cc_platform_has(CC_ATTR_HOST_SEV_SNP);
 
 out:
 	if (boot_cpu_has(X86_FEATURE_SEV))
@@ -2439,9 +2974,15 @@ out:
 		pr_info("SEV-ES %s (ASIDs %u - %u)\n",
 			sev_es_supported ? "enabled" : "disabled",
 			min_sev_asid > 1 ? 1 : 0, min_sev_asid - 1);
+	if (boot_cpu_has(X86_FEATURE_SEV_SNP))
+		pr_info("SEV-SNP %s (ASIDs %u - %u)\n",
+			sev_snp_supported ? "enabled" : "disabled",
+			min_sev_asid > 1 ? 1 : 0, min_sev_asid - 1);
 
 	sev_enabled = sev_supported;
 	sev_es_enabled = sev_es_supported;
+	sev_snp_enabled = sev_snp_supported;
+
 	if (!sev_es_enabled || !cpu_feature_enabled(X86_FEATURE_DEBUG_SWAP) ||
 	    !cpu_feature_enabled(X86_FEATURE_NO_NESTED_DATA_BP))
 		sev_es_debug_swap_enabled = false;
@@ -2520,7 +3061,13 @@ do_wbinvd:
 
 void sev_guest_memory_reclaimed(struct kvm *kvm)
 {
-	if (!sev_guest(kvm))
+	/*
+	 * With SNP+gmem, private/encrypted memory is unreachable via the
+	 * hva-based mmu notifiers, so these events are only actually
+	 * pertaining to shared pages where there is no need to perform
+	 * the WBINVD to flush associated caches.
+	 */
+	if (!sev_guest(kvm) || sev_snp_guest(kvm))
 		return;
 
 	wbinvd_on_all_cpus();
@@ -2535,11 +3082,24 @@ void sev_free_vcpu(struct kvm_vcpu *vcpu)
 
 	svm = to_svm(vcpu);
 
+	/*
+	 * If it's an SNP guest, then the VMSA was marked in the RMP table as
+	 * a guest-owned page. Transition the page to hypervisor state before
+	 * releasing it back to the system.
+	 */
+	if (sev_snp_guest(vcpu->kvm)) {
+		u64 pfn = __pa(svm->sev_es.vmsa) >> PAGE_SHIFT;
+
+		if (kvm_rmp_make_shared(vcpu->kvm, pfn, PG_LEVEL_4K))
+			goto skip_vmsa_free;
+	}
+
 	if (vcpu->arch.guest_state_protected)
 		sev_flush_encrypted_page(vcpu, svm->sev_es.vmsa);
 
 	__free_page(virt_to_page(svm->sev_es.vmsa));
 
+skip_vmsa_free:
 	if (svm->sev_es.ghcb_sa_free)
 		kvfree(svm->sev_es.ghcb_sa);
 }
@@ -2735,6 +3295,13 @@ static int sev_es_validate_vmgexit(struct vcpu_svm *svm)
 		if (!kvm_ghcb_sw_scratch_is_valid(svm))
 			goto vmgexit_err;
 		break;
+	case SVM_VMGEXIT_AP_CREATION:
+		if (!sev_snp_guest(vcpu->kvm))
+			goto vmgexit_err;
+		if (lower_32_bits(control->exit_info_1) != SVM_VMGEXIT_AP_DESTROY)
+			if (!kvm_ghcb_rax_is_valid(svm))
+				goto vmgexit_err;
+		break;
 	case SVM_VMGEXIT_NMI_COMPLETE:
 	case SVM_VMGEXIT_AP_HLT_LOOP:
 	case SVM_VMGEXIT_AP_JUMP_TABLE:
@@ -2742,6 +3309,10 @@ static int sev_es_validate_vmgexit(struct vcpu_svm *svm)
 	case SVM_VMGEXIT_HV_FEATURES:
 	case SVM_VMGEXIT_TERM_REQUEST:
 		break;
+	case SVM_VMGEXIT_PSC:
+		if (!sev_snp_guest(vcpu->kvm) || !kvm_ghcb_sw_scratch_is_valid(svm))
+			goto vmgexit_err;
+		break;
 	default:
 		reason = GHCB_ERR_INVALID_EVENT;
 		goto vmgexit_err;
@@ -2929,6 +3500,437 @@ static void set_ghcb_msr(struct vcpu_svm *svm, u64 value)
 	svm->vmcb->control.ghcb_gpa = value;
 }
 
+static int snp_rmptable_psmash(kvm_pfn_t pfn)
+{
+	int ret;
+
+	pfn = pfn & ~(KVM_PAGES_PER_HPAGE(PG_LEVEL_2M) - 1);
+
+	/*
+	 * PSMASH_FAIL_INUSE indicates another processor is modifying the
+	 * entry, so retry until that's no longer the case.
+	 */
+	do {
+		ret = psmash(pfn);
+	} while (ret == PSMASH_FAIL_INUSE);
+
+	return ret;
+}
+
+static int snp_complete_psc_msr(struct kvm_vcpu *vcpu)
+{
+	struct vcpu_svm *svm = to_svm(vcpu);
+
+	if (vcpu->run->hypercall.ret)
+		set_ghcb_msr(svm, GHCB_MSR_PSC_RESP_ERROR);
+	else
+		set_ghcb_msr(svm, GHCB_MSR_PSC_RESP);
+
+	return 1; /* resume guest */
+}
+
+static int snp_begin_psc_msr(struct vcpu_svm *svm, u64 ghcb_msr)
+{
+	u64 gpa = gfn_to_gpa(GHCB_MSR_PSC_REQ_TO_GFN(ghcb_msr));
+	u8 op = GHCB_MSR_PSC_REQ_TO_OP(ghcb_msr);
+	struct kvm_vcpu *vcpu = &svm->vcpu;
+
+	if (op != SNP_PAGE_STATE_PRIVATE && op != SNP_PAGE_STATE_SHARED) {
+		set_ghcb_msr(svm, GHCB_MSR_PSC_RESP_ERROR);
+		return 1; /* resume guest */
+	}
+
+	if (!(vcpu->kvm->arch.hypercall_exit_enabled & (1 << KVM_HC_MAP_GPA_RANGE))) {
+		set_ghcb_msr(svm, GHCB_MSR_PSC_RESP_ERROR);
+		return 1; /* resume guest */
+	}
+
+	vcpu->run->exit_reason = KVM_EXIT_HYPERCALL;
+	vcpu->run->hypercall.nr = KVM_HC_MAP_GPA_RANGE;
+	vcpu->run->hypercall.args[0] = gpa;
+	vcpu->run->hypercall.args[1] = 1;
+	vcpu->run->hypercall.args[2] = (op == SNP_PAGE_STATE_PRIVATE)
+				       ? KVM_MAP_GPA_RANGE_ENCRYPTED
+				       : KVM_MAP_GPA_RANGE_DECRYPTED;
+	vcpu->run->hypercall.args[2] |= KVM_MAP_GPA_RANGE_PAGE_SZ_4K;
+
+	vcpu->arch.complete_userspace_io = snp_complete_psc_msr;
+
+	return 0; /* forward request to userspace */
+}
+
+struct psc_buffer {
+	struct psc_hdr hdr;
+	struct psc_entry entries[];
+} __packed;
+
+static int snp_begin_psc(struct vcpu_svm *svm, struct psc_buffer *psc);
+
+static void snp_complete_psc(struct vcpu_svm *svm, u64 psc_ret)
+{
+	svm->sev_es.psc_inflight = 0;
+	svm->sev_es.psc_idx = 0;
+	svm->sev_es.psc_2m = false;
+	ghcb_set_sw_exit_info_2(svm->sev_es.ghcb, psc_ret);
+}
+
+static void __snp_complete_one_psc(struct vcpu_svm *svm)
+{
+	struct psc_buffer *psc = svm->sev_es.ghcb_sa;
+	struct psc_entry *entries = psc->entries;
+	struct psc_hdr *hdr = &psc->hdr;
+	__u16 idx;
+
+	/*
+	 * Everything in-flight has been processed successfully. Update the
+	 * corresponding entries in the guest's PSC buffer and zero out the
+	 * count of in-flight PSC entries.
+	 */
+	for (idx = svm->sev_es.psc_idx; svm->sev_es.psc_inflight;
+	     svm->sev_es.psc_inflight--, idx++) {
+		struct psc_entry *entry = &entries[idx];
+
+		entry->cur_page = entry->pagesize ? 512 : 1;
+	}
+
+	hdr->cur_entry = idx;
+}
+
+static int snp_complete_one_psc(struct kvm_vcpu *vcpu)
+{
+	struct vcpu_svm *svm = to_svm(vcpu);
+	struct psc_buffer *psc = svm->sev_es.ghcb_sa;
+
+	if (vcpu->run->hypercall.ret) {
+		snp_complete_psc(svm, VMGEXIT_PSC_ERROR_GENERIC);
+		return 1; /* resume guest */
+	}
+
+	__snp_complete_one_psc(svm);
+
+	/* Handle the next range (if any). */
+	return snp_begin_psc(svm, psc);
+}
+
+static int snp_begin_psc(struct vcpu_svm *svm, struct psc_buffer *psc)
+{
+	struct psc_entry *entries = psc->entries;
+	struct kvm_vcpu *vcpu = &svm->vcpu;
+	struct psc_hdr *hdr = &psc->hdr;
+	struct psc_entry entry_start;
+	u16 idx, idx_start, idx_end;
+	int npages;
+	bool huge;
+	u64 gfn;
+
+	if (!(vcpu->kvm->arch.hypercall_exit_enabled & (1 << KVM_HC_MAP_GPA_RANGE))) {
+		snp_complete_psc(svm, VMGEXIT_PSC_ERROR_GENERIC);
+		return 1;
+	}
+
+next_range:
+	/* There should be no other PSCs in-flight at this point. */
+	if (WARN_ON_ONCE(svm->sev_es.psc_inflight)) {
+		snp_complete_psc(svm, VMGEXIT_PSC_ERROR_GENERIC);
+		return 1;
+	}
+
+	/*
+	 * The PSC descriptor buffer can be modified by a misbehaved guest after
+	 * validation, so take care to only use validated copies of values used
+	 * for things like array indexing.
+	 */
+	idx_start = hdr->cur_entry;
+	idx_end = hdr->end_entry;
+
+	if (idx_end >= VMGEXIT_PSC_MAX_COUNT) {
+		snp_complete_psc(svm, VMGEXIT_PSC_ERROR_INVALID_HDR);
+		return 1;
+	}
+
+	/* Find the start of the next range which needs processing. */
+	for (idx = idx_start; idx <= idx_end; idx++, hdr->cur_entry++) {
+		entry_start = entries[idx];
+
+		gfn = entry_start.gfn;
+		huge = entry_start.pagesize;
+		npages = huge ? 512 : 1;
+
+		if (entry_start.cur_page > npages || !IS_ALIGNED(gfn, npages)) {
+			snp_complete_psc(svm, VMGEXIT_PSC_ERROR_INVALID_ENTRY);
+			return 1;
+		}
+
+		if (entry_start.cur_page) {
+			/*
+			 * If this is a partially-completed 2M range, force 4K handling
+			 * for the remaining pages since they're effectively split at
+			 * this point. Subsequent code should ensure this doesn't get
+			 * combined with adjacent PSC entries where 2M handling is still
+			 * possible.
+			 */
+			npages -= entry_start.cur_page;
+			gfn += entry_start.cur_page;
+			huge = false;
+		}
+
+		if (npages)
+			break;
+	}
+
+	if (idx > idx_end) {
+		/* Nothing more to process. */
+		snp_complete_psc(svm, 0);
+		return 1;
+	}
+
+	svm->sev_es.psc_2m = huge;
+	svm->sev_es.psc_idx = idx;
+	svm->sev_es.psc_inflight = 1;
+
+	/*
+	 * Find all subsequent PSC entries that contain adjacent GPA
+	 * ranges/operations and can be combined into a single
+	 * KVM_HC_MAP_GPA_RANGE exit.
+	 */
+	while (++idx <= idx_end) {
+		struct psc_entry entry = entries[idx];
+
+		if (entry.operation != entry_start.operation ||
+		    entry.gfn != entry_start.gfn + npages ||
+		    entry.cur_page || !!entry.pagesize != huge)
+			break;
+
+		svm->sev_es.psc_inflight++;
+		npages += huge ? 512 : 1;
+	}
+
+	switch (entry_start.operation) {
+	case VMGEXIT_PSC_OP_PRIVATE:
+	case VMGEXIT_PSC_OP_SHARED:
+		vcpu->run->exit_reason = KVM_EXIT_HYPERCALL;
+		vcpu->run->hypercall.nr = KVM_HC_MAP_GPA_RANGE;
+		vcpu->run->hypercall.args[0] = gfn_to_gpa(gfn);
+		vcpu->run->hypercall.args[1] = npages;
+		vcpu->run->hypercall.args[2] = entry_start.operation == VMGEXIT_PSC_OP_PRIVATE
+					       ? KVM_MAP_GPA_RANGE_ENCRYPTED
+					       : KVM_MAP_GPA_RANGE_DECRYPTED;
+		vcpu->run->hypercall.args[2] |= entry_start.pagesize
+						? KVM_MAP_GPA_RANGE_PAGE_SZ_2M
+						: KVM_MAP_GPA_RANGE_PAGE_SZ_4K;
+		vcpu->arch.complete_userspace_io = snp_complete_one_psc;
+		return 0; /* forward request to userspace */
+	default:
+		/*
+		 * Only shared/private PSC operations are currently supported, so if the
+		 * entire range consists of unsupported operations (e.g. SMASH/UNSMASH),
+		 * then consider the entire range completed and avoid exiting to
+		 * userspace. In theory snp_complete_psc() can always be called directly
+		 * at this point to complete the current range and start the next one,
+		 * but that could lead to unexpected levels of recursion.
+		 */
+		__snp_complete_one_psc(svm);
+		goto next_range;
+	}
+
+	unreachable();
+}
+
+static int __sev_snp_update_protected_guest_state(struct kvm_vcpu *vcpu)
+{
+	struct vcpu_svm *svm = to_svm(vcpu);
+
+	WARN_ON(!mutex_is_locked(&svm->sev_es.snp_vmsa_mutex));
+
+	/* Mark the vCPU as offline and not runnable */
+	vcpu->arch.pv.pv_unhalted = false;
+	vcpu->arch.mp_state = KVM_MP_STATE_HALTED;
+
+	/* Clear use of the VMSA */
+	svm->vmcb->control.vmsa_pa = INVALID_PAGE;
+
+	if (VALID_PAGE(svm->sev_es.snp_vmsa_gpa)) {
+		gfn_t gfn = gpa_to_gfn(svm->sev_es.snp_vmsa_gpa);
+		struct kvm_memory_slot *slot;
+		kvm_pfn_t pfn;
+
+		slot = gfn_to_memslot(vcpu->kvm, gfn);
+		if (!slot)
+			return -EINVAL;
+
+		/*
+		 * The new VMSA will be private memory guest memory, so
+		 * retrieve the PFN from the gmem backend.
+		 */
+		if (kvm_gmem_get_pfn(vcpu->kvm, slot, gfn, &pfn, NULL))
+			return -EINVAL;
+
+		/*
+		 * From this point forward, the VMSA will always be a
+		 * guest-mapped page rather than the initial one allocated
+		 * by KVM in svm->sev_es.vmsa. In theory, svm->sev_es.vmsa
+		 * could be free'd and cleaned up here, but that involves
+		 * cleanups like wbinvd_on_all_cpus() which would ideally
+		 * be handled during teardown rather than guest boot.
+		 * Deferring that also allows the existing logic for SEV-ES
+		 * VMSAs to be re-used with minimal SNP-specific changes.
+		 */
+		svm->sev_es.snp_has_guest_vmsa = true;
+
+		/* Use the new VMSA */
+		svm->vmcb->control.vmsa_pa = pfn_to_hpa(pfn);
+
+		/* Mark the vCPU as runnable */
+		vcpu->arch.pv.pv_unhalted = false;
+		vcpu->arch.mp_state = KVM_MP_STATE_RUNNABLE;
+
+		svm->sev_es.snp_vmsa_gpa = INVALID_PAGE;
+
+		/*
+		 * gmem pages aren't currently migratable, but if this ever
+		 * changes then care should be taken to ensure
+		 * svm->sev_es.vmsa is pinned through some other means.
+		 */
+		kvm_release_pfn_clean(pfn);
+	}
+
+	/*
+	 * When replacing the VMSA during SEV-SNP AP creation,
+	 * mark the VMCB dirty so that full state is always reloaded.
+	 */
+	vmcb_mark_all_dirty(svm->vmcb);
+
+	return 0;
+}
+
+/*
+ * Invoked as part of svm_vcpu_reset() processing of an init event.
+ */
+void sev_snp_init_protected_guest_state(struct kvm_vcpu *vcpu)
+{
+	struct vcpu_svm *svm = to_svm(vcpu);
+	int ret;
+
+	if (!sev_snp_guest(vcpu->kvm))
+		return;
+
+	mutex_lock(&svm->sev_es.snp_vmsa_mutex);
+
+	if (!svm->sev_es.snp_ap_waiting_for_reset)
+		goto unlock;
+
+	svm->sev_es.snp_ap_waiting_for_reset = false;
+
+	ret = __sev_snp_update_protected_guest_state(vcpu);
+	if (ret)
+		vcpu_unimpl(vcpu, "snp: AP state update on init failed\n");
+
+unlock:
+	mutex_unlock(&svm->sev_es.snp_vmsa_mutex);
+}
+
+static int sev_snp_ap_creation(struct vcpu_svm *svm)
+{
+	struct kvm_sev_info *sev = &to_kvm_svm(svm->vcpu.kvm)->sev_info;
+	struct kvm_vcpu *vcpu = &svm->vcpu;
+	struct kvm_vcpu *target_vcpu;
+	struct vcpu_svm *target_svm;
+	unsigned int request;
+	unsigned int apic_id;
+	bool kick;
+	int ret;
+
+	request = lower_32_bits(svm->vmcb->control.exit_info_1);
+	apic_id = upper_32_bits(svm->vmcb->control.exit_info_1);
+
+	/* Validate the APIC ID */
+	target_vcpu = kvm_get_vcpu_by_id(vcpu->kvm, apic_id);
+	if (!target_vcpu) {
+		vcpu_unimpl(vcpu, "vmgexit: invalid AP APIC ID [%#x] from guest\n",
+			    apic_id);
+		return -EINVAL;
+	}
+
+	ret = 0;
+
+	target_svm = to_svm(target_vcpu);
+
+	/*
+	 * The target vCPU is valid, so the vCPU will be kicked unless the
+	 * request is for CREATE_ON_INIT. For any errors at this stage, the
+	 * kick will place the vCPU in an non-runnable state.
+	 */
+	kick = true;
+
+	mutex_lock(&target_svm->sev_es.snp_vmsa_mutex);
+
+	target_svm->sev_es.snp_vmsa_gpa = INVALID_PAGE;
+	target_svm->sev_es.snp_ap_waiting_for_reset = true;
+
+	/* Interrupt injection mode shouldn't change for AP creation */
+	if (request < SVM_VMGEXIT_AP_DESTROY) {
+		u64 sev_features;
+
+		sev_features = vcpu->arch.regs[VCPU_REGS_RAX];
+		sev_features ^= sev->vmsa_features;
+
+		if (sev_features & SVM_SEV_FEAT_INT_INJ_MODES) {
+			vcpu_unimpl(vcpu, "vmgexit: invalid AP injection mode [%#lx] from guest\n",
+				    vcpu->arch.regs[VCPU_REGS_RAX]);
+			ret = -EINVAL;
+			goto out;
+		}
+	}
+
+	switch (request) {
+	case SVM_VMGEXIT_AP_CREATE_ON_INIT:
+		kick = false;
+		fallthrough;
+	case SVM_VMGEXIT_AP_CREATE:
+		if (!page_address_valid(vcpu, svm->vmcb->control.exit_info_2)) {
+			vcpu_unimpl(vcpu, "vmgexit: invalid AP VMSA address [%#llx] from guest\n",
+				    svm->vmcb->control.exit_info_2);
+			ret = -EINVAL;
+			goto out;
+		}
+
+		/*
+		 * Malicious guest can RMPADJUST a large page into VMSA which
+		 * will hit the SNP erratum where the CPU will incorrectly signal
+		 * an RMP violation #PF if a hugepage collides with the RMP entry
+		 * of VMSA page, reject the AP CREATE request if VMSA address from
+		 * guest is 2M aligned.
+		 */
+		if (IS_ALIGNED(svm->vmcb->control.exit_info_2, PMD_SIZE)) {
+			vcpu_unimpl(vcpu,
+				    "vmgexit: AP VMSA address [%llx] from guest is unsafe as it is 2M aligned\n",
+				    svm->vmcb->control.exit_info_2);
+			ret = -EINVAL;
+			goto out;
+		}
+
+		target_svm->sev_es.snp_vmsa_gpa = svm->vmcb->control.exit_info_2;
+		break;
+	case SVM_VMGEXIT_AP_DESTROY:
+		break;
+	default:
+		vcpu_unimpl(vcpu, "vmgexit: invalid AP creation request [%#x] from guest\n",
+			    request);
+		ret = -EINVAL;
+		break;
+	}
+
+out:
+	if (kick) {
+		kvm_make_request(KVM_REQ_UPDATE_PROTECTED_GUEST_STATE, target_vcpu);
+		kvm_vcpu_kick(target_vcpu);
+	}
+
+	mutex_unlock(&target_svm->sev_es.snp_vmsa_mutex);
+
+	return ret;
+}
+
 static int sev_handle_vmgexit_msr_protocol(struct vcpu_svm *svm)
 {
 	struct vmcb_control_area *control = &svm->vmcb->control;
@@ -3008,6 +4010,38 @@ static int sev_handle_vmgexit_msr_protocol(struct vcpu_svm *svm)
 		set_ghcb_msr_bits(svm, GHCB_MSR_HV_FT_RESP,
 				  GHCB_MSR_INFO_MASK, GHCB_MSR_INFO_POS);
 		break;
+	case GHCB_MSR_PREF_GPA_REQ:
+		if (!sev_snp_guest(vcpu->kvm))
+			goto out_terminate;
+
+		set_ghcb_msr_bits(svm, GHCB_MSR_PREF_GPA_NONE, GHCB_MSR_GPA_VALUE_MASK,
+				  GHCB_MSR_GPA_VALUE_POS);
+		set_ghcb_msr_bits(svm, GHCB_MSR_PREF_GPA_RESP, GHCB_MSR_INFO_MASK,
+				  GHCB_MSR_INFO_POS);
+		break;
+	case GHCB_MSR_REG_GPA_REQ: {
+		u64 gfn;
+
+		if (!sev_snp_guest(vcpu->kvm))
+			goto out_terminate;
+
+		gfn = get_ghcb_msr_bits(svm, GHCB_MSR_GPA_VALUE_MASK,
+					GHCB_MSR_GPA_VALUE_POS);
+
+		svm->sev_es.ghcb_registered_gpa = gfn_to_gpa(gfn);
+
+		set_ghcb_msr_bits(svm, gfn, GHCB_MSR_GPA_VALUE_MASK,
+				  GHCB_MSR_GPA_VALUE_POS);
+		set_ghcb_msr_bits(svm, GHCB_MSR_REG_GPA_RESP, GHCB_MSR_INFO_MASK,
+				  GHCB_MSR_INFO_POS);
+		break;
+	}
+	case GHCB_MSR_PSC_REQ:
+		if (!sev_snp_guest(vcpu->kvm))
+			goto out_terminate;
+
+		ret = snp_begin_psc_msr(svm, control->ghcb_gpa);
+		break;
 	case GHCB_MSR_TERM_REQ: {
 		u64 reason_set, reason_code;
 
@@ -3020,12 +4054,7 @@ static int sev_handle_vmgexit_msr_protocol(struct vcpu_svm *svm)
 		pr_info("SEV-ES guest requested termination: %#llx:%#llx\n",
 			reason_set, reason_code);
 
-		vcpu->run->exit_reason = KVM_EXIT_SYSTEM_EVENT;
-		vcpu->run->system_event.type = KVM_SYSTEM_EVENT_SEV_TERM;
-		vcpu->run->system_event.ndata = 1;
-		vcpu->run->system_event.data[0] = control->ghcb_gpa;
-
-		return 0;
+		goto out_terminate;
 	}
 	default:
 		/* Error, keep GHCB MSR value as-is */
@@ -3036,6 +4065,14 @@ static int sev_handle_vmgexit_msr_protocol(struct vcpu_svm *svm)
 					    control->ghcb_gpa, ret);
 
 	return ret;
+
+out_terminate:
+	vcpu->run->exit_reason = KVM_EXIT_SYSTEM_EVENT;
+	vcpu->run->system_event.type = KVM_SYSTEM_EVENT_SEV_TERM;
+	vcpu->run->system_event.ndata = 1;
+	vcpu->run->system_event.data[0] = control->ghcb_gpa;
+
+	return 0;
 }
 
 int sev_handle_vmgexit(struct kvm_vcpu *vcpu)
@@ -3071,6 +4108,13 @@ int sev_handle_vmgexit(struct kvm_vcpu *vcpu)
 	trace_kvm_vmgexit_enter(vcpu->vcpu_id, svm->sev_es.ghcb);
 
 	sev_es_sync_from_ghcb(svm);
+
+	/* SEV-SNP guest requires that the GHCB GPA must be registered */
+	if (sev_snp_guest(svm->vcpu.kvm) && !ghcb_gpa_is_registered(svm, ghcb_gpa)) {
+		vcpu_unimpl(&svm->vcpu, "vmgexit: GHCB GPA [%#llx] is not registered.\n", ghcb_gpa);
+		return -EINVAL;
+	}
+
 	ret = sev_es_validate_vmgexit(svm);
 	if (ret)
 		return ret;
@@ -3145,6 +4189,22 @@ int sev_handle_vmgexit(struct kvm_vcpu *vcpu)
 		vcpu->run->system_event.ndata = 1;
 		vcpu->run->system_event.data[0] = control->ghcb_gpa;
 		break;
+	case SVM_VMGEXIT_PSC:
+		ret = setup_vmgexit_scratch(svm, true, control->exit_info_2);
+		if (ret)
+			break;
+
+		ret = snp_begin_psc(svm, svm->sev_es.ghcb_sa);
+		break;
+	case SVM_VMGEXIT_AP_CREATION:
+		ret = sev_snp_ap_creation(svm);
+		if (ret) {
+			ghcb_set_sw_exit_info_1(svm->sev_es.ghcb, 2);
+			ghcb_set_sw_exit_info_2(svm->sev_es.ghcb, GHCB_ERR_INVALID_INPUT);
+		}
+
+		ret = 1;
+		break;
 	case SVM_VMGEXIT_UNSUPPORTED_EVENT:
 		vcpu_unimpl(vcpu,
 			    "vmgexit: unsupported event - exit_info_1=%#llx, exit_info_2=%#llx\n",
@@ -3238,7 +4298,7 @@ static void sev_es_init_vmcb(struct vcpu_svm *svm)
 	 * the VMSA will be NULL if this vCPU is the destination for intrahost
 	 * migration, and will be copied later.
 	 */
-	if (svm->sev_es.vmsa)
+	if (svm->sev_es.vmsa && !svm->sev_es.snp_has_guest_vmsa)
 		svm->vmcb->control.vmsa_pa = __pa(svm->sev_es.vmsa);
 
 	/* Can't intercept CR register access, HV can't modify CR registers */
@@ -3310,6 +4370,8 @@ void sev_es_vcpu_reset(struct vcpu_svm *svm)
 	set_ghcb_msr(svm, GHCB_MSR_SEV_INFO((__u64)sev->ghcb_version,
 					    GHCB_VERSION_MIN,
 					    sev_enc_bit));
+
+	mutex_init(&svm->sev_es.snp_vmsa_mutex);
 }
 
 void sev_es_prepare_switch_to_guest(struct vcpu_svm *svm, struct sev_es_save_area *hostsa)
@@ -3420,3 +4482,271 @@ struct page *snp_safe_alloc_page(struct kvm_vcpu *vcpu)
 
 	return p;
 }
+
+void sev_handle_rmp_fault(struct kvm_vcpu *vcpu, gpa_t gpa, u64 error_code)
+{
+	struct kvm_memory_slot *slot;
+	struct kvm *kvm = vcpu->kvm;
+	int order, rmp_level, ret;
+	bool assigned;
+	kvm_pfn_t pfn;
+	gfn_t gfn;
+
+	gfn = gpa >> PAGE_SHIFT;
+
+	/*
+	 * The only time RMP faults occur for shared pages is when the guest is
+	 * triggering an RMP fault for an implicit page-state change from
+	 * shared->private. Implicit page-state changes are forwarded to
+	 * userspace via KVM_EXIT_MEMORY_FAULT events, however, so RMP faults
+	 * for shared pages should not end up here.
+	 */
+	if (!kvm_mem_is_private(kvm, gfn)) {
+		pr_warn_ratelimited("SEV: Unexpected RMP fault for non-private GPA 0x%llx\n",
+				    gpa);
+		return;
+	}
+
+	slot = gfn_to_memslot(kvm, gfn);
+	if (!kvm_slot_can_be_private(slot)) {
+		pr_warn_ratelimited("SEV: Unexpected RMP fault, non-private slot for GPA 0x%llx\n",
+				    gpa);
+		return;
+	}
+
+	ret = kvm_gmem_get_pfn(kvm, slot, gfn, &pfn, &order);
+	if (ret) {
+		pr_warn_ratelimited("SEV: Unexpected RMP fault, no backing page for private GPA 0x%llx\n",
+				    gpa);
+		return;
+	}
+
+	ret = snp_lookup_rmpentry(pfn, &assigned, &rmp_level);
+	if (ret || !assigned) {
+		pr_warn_ratelimited("SEV: Unexpected RMP fault, no assigned RMP entry found for GPA 0x%llx PFN 0x%llx error %d\n",
+				    gpa, pfn, ret);
+		goto out_no_trace;
+	}
+
+	/*
+	 * There are 2 cases where a PSMASH may be needed to resolve an #NPF
+	 * with PFERR_GUEST_RMP_BIT set:
+	 *
+	 * 1) RMPADJUST/PVALIDATE can trigger an #NPF with PFERR_GUEST_SIZEM
+	 *    bit set if the guest issues them with a smaller granularity than
+	 *    what is indicated by the page-size bit in the 2MB RMP entry for
+	 *    the PFN that backs the GPA.
+	 *
+	 * 2) Guest access via NPT can trigger an #NPF if the NPT mapping is
+	 *    smaller than what is indicated by the 2MB RMP entry for the PFN
+	 *    that backs the GPA.
+	 *
+	 * In both these cases, the corresponding 2M RMP entry needs to
+	 * be PSMASH'd to 512 4K RMP entries.  If the RMP entry is already
+	 * split into 4K RMP entries, then this is likely a spurious case which
+	 * can occur when there are concurrent accesses by the guest to a 2MB
+	 * GPA range that is backed by a 2MB-aligned PFN who's RMP entry is in
+	 * the process of being PMASH'd into 4K entries. These cases should
+	 * resolve automatically on subsequent accesses, so just ignore them
+	 * here.
+	 */
+	if (rmp_level == PG_LEVEL_4K)
+		goto out;
+
+	ret = snp_rmptable_psmash(pfn);
+	if (ret) {
+		/*
+		 * Look it up again. If it's 4K now then the PSMASH may have
+		 * raced with another process and the issue has already resolved
+		 * itself.
+		 */
+		if (!snp_lookup_rmpentry(pfn, &assigned, &rmp_level) &&
+		    assigned && rmp_level == PG_LEVEL_4K)
+			goto out;
+
+		pr_warn_ratelimited("SEV: Unable to split RMP entry for GPA 0x%llx PFN 0x%llx ret %d\n",
+				    gpa, pfn, ret);
+	}
+
+	kvm_zap_gfn_range(kvm, gfn, gfn + PTRS_PER_PMD);
+out:
+	trace_kvm_rmp_fault(vcpu, gpa, pfn, error_code, rmp_level, ret);
+out_no_trace:
+	put_page(pfn_to_page(pfn));
+}
+
+static bool is_pfn_range_shared(kvm_pfn_t start, kvm_pfn_t end)
+{
+	kvm_pfn_t pfn = start;
+
+	while (pfn < end) {
+		int ret, rmp_level;
+		bool assigned;
+
+		ret = snp_lookup_rmpentry(pfn, &assigned, &rmp_level);
+		if (ret) {
+			pr_warn_ratelimited("SEV: Failed to retrieve RMP entry: PFN 0x%llx GFN start 0x%llx GFN end 0x%llx RMP level %d error %d\n",
+					    pfn, start, end, rmp_level, ret);
+			return false;
+		}
+
+		if (assigned) {
+			pr_debug("%s: overlap detected, PFN 0x%llx start 0x%llx end 0x%llx RMP level %d\n",
+				 __func__, pfn, start, end, rmp_level);
+			return false;
+		}
+
+		pfn++;
+	}
+
+	return true;
+}
+
+static u8 max_level_for_order(int order)
+{
+	if (order >= KVM_HPAGE_GFN_SHIFT(PG_LEVEL_2M))
+		return PG_LEVEL_2M;
+
+	return PG_LEVEL_4K;
+}
+
+static bool is_large_rmp_possible(struct kvm *kvm, kvm_pfn_t pfn, int order)
+{
+	kvm_pfn_t pfn_aligned = ALIGN_DOWN(pfn, PTRS_PER_PMD);
+
+	/*
+	 * If this is a large folio, and the entire 2M range containing the
+	 * PFN is currently shared, then the entire 2M-aligned range can be
+	 * set to private via a single 2M RMP entry.
+	 */
+	if (max_level_for_order(order) > PG_LEVEL_4K &&
+	    is_pfn_range_shared(pfn_aligned, pfn_aligned + PTRS_PER_PMD))
+		return true;
+
+	return false;
+}
+
+int sev_gmem_prepare(struct kvm *kvm, kvm_pfn_t pfn, gfn_t gfn, int max_order)
+{
+	struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
+	kvm_pfn_t pfn_aligned;
+	gfn_t gfn_aligned;
+	int level, rc;
+	bool assigned;
+
+	if (!sev_snp_guest(kvm))
+		return 0;
+
+	rc = snp_lookup_rmpentry(pfn, &assigned, &level);
+	if (rc) {
+		pr_err_ratelimited("SEV: Failed to look up RMP entry: GFN %llx PFN %llx error %d\n",
+				   gfn, pfn, rc);
+		return -ENOENT;
+	}
+
+	if (assigned) {
+		pr_debug("%s: already assigned: gfn %llx pfn %llx max_order %d level %d\n",
+			 __func__, gfn, pfn, max_order, level);
+		return 0;
+	}
+
+	if (is_large_rmp_possible(kvm, pfn, max_order)) {
+		level = PG_LEVEL_2M;
+		pfn_aligned = ALIGN_DOWN(pfn, PTRS_PER_PMD);
+		gfn_aligned = ALIGN_DOWN(gfn, PTRS_PER_PMD);
+	} else {
+		level = PG_LEVEL_4K;
+		pfn_aligned = pfn;
+		gfn_aligned = gfn;
+	}
+
+	rc = rmp_make_private(pfn_aligned, gfn_to_gpa(gfn_aligned), level, sev->asid, false);
+	if (rc) {
+		pr_err_ratelimited("SEV: Failed to update RMP entry: GFN %llx PFN %llx level %d error %d\n",
+				   gfn, pfn, level, rc);
+		return -EINVAL;
+	}
+
+	pr_debug("%s: updated: gfn %llx pfn %llx pfn_aligned %llx max_order %d level %d\n",
+		 __func__, gfn, pfn, pfn_aligned, max_order, level);
+
+	return 0;
+}
+
+void sev_gmem_invalidate(kvm_pfn_t start, kvm_pfn_t end)
+{
+	kvm_pfn_t pfn;
+
+	if (!cc_platform_has(CC_ATTR_HOST_SEV_SNP))
+		return;
+
+	pr_debug("%s: PFN start 0x%llx PFN end 0x%llx\n", __func__, start, end);
+
+	for (pfn = start; pfn < end;) {
+		bool use_2m_update = false;
+		int rc, rmp_level;
+		bool assigned;
+
+		rc = snp_lookup_rmpentry(pfn, &assigned, &rmp_level);
+		if (rc || !assigned)
+			goto next_pfn;
+
+		use_2m_update = IS_ALIGNED(pfn, PTRS_PER_PMD) &&
+				end >= (pfn + PTRS_PER_PMD) &&
+				rmp_level > PG_LEVEL_4K;
+
+		/*
+		 * If an unaligned PFN corresponds to a 2M region assigned as a
+		 * large page in the RMP table, PSMASH the region into individual
+		 * 4K RMP entries before attempting to convert a 4K sub-page.
+		 */
+		if (!use_2m_update && rmp_level > PG_LEVEL_4K) {
+			/*
+			 * This shouldn't fail, but if it does, report it, but
+			 * still try to update RMP entry to shared and pray this
+			 * was a spurious error that can be addressed later.
+			 */
+			rc = snp_rmptable_psmash(pfn);
+			WARN_ONCE(rc, "SEV: Failed to PSMASH RMP entry for PFN 0x%llx error %d\n",
+				  pfn, rc);
+		}
+
+		rc = rmp_make_shared(pfn, use_2m_update ? PG_LEVEL_2M : PG_LEVEL_4K);
+		if (WARN_ONCE(rc, "SEV: Failed to update RMP entry for PFN 0x%llx error %d\n",
+			      pfn, rc))
+			goto next_pfn;
+
+		/*
+		 * SEV-ES avoids host/guest cache coherency issues through
+		 * WBINVD hooks issued via MMU notifiers during run-time, and
+		 * KVM's VM destroy path at shutdown. Those MMU notifier events
+		 * don't cover gmem since there is no requirement to map pages
+		 * to a HVA in order to use them for a running guest. While the
+		 * shutdown path would still likely cover things for SNP guests,
+		 * userspace may also free gmem pages during run-time via
+		 * hole-punching operations on the guest_memfd, so flush the
+		 * cache entries for these pages before free'ing them back to
+		 * the host.
+		 */
+		clflush_cache_range(__va(pfn_to_hpa(pfn)),
+				    use_2m_update ? PMD_SIZE : PAGE_SIZE);
+next_pfn:
+		pfn += use_2m_update ? PTRS_PER_PMD : 1;
+		cond_resched();
+	}
+}
+
+int sev_private_max_mapping_level(struct kvm *kvm, kvm_pfn_t pfn)
+{
+	int level, rc;
+	bool assigned;
+
+	if (!sev_snp_guest(kvm))
+		return 0;
+
+	rc = snp_lookup_rmpentry(pfn, &assigned, &level);
+	if (rc || !assigned)
+		return PG_LEVEL_4K;
+
+	return level;
+}
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 296c524988f9..b252a2732b6f 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -1404,6 +1404,9 @@ static void svm_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event)
 	svm->spec_ctrl = 0;
 	svm->virt_spec_ctrl = 0;
 
+	if (init_event)
+		sev_snp_init_protected_guest_state(vcpu);
+
 	init_vmcb(vcpu);
 
 	if (!init_event)
@@ -2050,6 +2053,7 @@ static int pf_interception(struct kvm_vcpu *vcpu)
 static int npf_interception(struct kvm_vcpu *vcpu)
 {
 	struct vcpu_svm *svm = to_svm(vcpu);
+	int rc;
 
 	u64 fault_address = svm->vmcb->control.exit_info_2;
 	u64 error_code = svm->vmcb->control.exit_info_1;
@@ -2063,11 +2067,19 @@ static int npf_interception(struct kvm_vcpu *vcpu)
 	if (WARN_ON_ONCE(error_code & PFERR_SYNTHETIC_MASK))
 		error_code &= ~PFERR_SYNTHETIC_MASK;
 
+	if (sev_snp_guest(vcpu->kvm) && (error_code & PFERR_GUEST_ENC_MASK))
+		error_code |= PFERR_PRIVATE_ACCESS;
+
 	trace_kvm_page_fault(vcpu, fault_address, error_code);
-	return kvm_mmu_page_fault(vcpu, fault_address, error_code,
-			static_cpu_has(X86_FEATURE_DECODEASSISTS) ?
-			svm->vmcb->control.insn_bytes : NULL,
-			svm->vmcb->control.insn_len);
+	rc = kvm_mmu_page_fault(vcpu, fault_address, error_code,
+				static_cpu_has(X86_FEATURE_DECODEASSISTS) ?
+				svm->vmcb->control.insn_bytes : NULL,
+				svm->vmcb->control.insn_len);
+
+	if (rc > 0 && error_code & PFERR_GUEST_RMP_MASK)
+		sev_handle_rmp_fault(vcpu, fault_address, error_code);
+
+	return rc;
 }
 
 static int db_interception(struct kvm_vcpu *vcpu)
@@ -4937,8 +4949,11 @@ static int svm_vm_init(struct kvm *kvm)
 
 	if (type != KVM_X86_DEFAULT_VM &&
 	    type != KVM_X86_SW_PROTECTED_VM) {
-		kvm->arch.has_protected_state = (type == KVM_X86_SEV_ES_VM);
+		kvm->arch.has_protected_state =
+			(type == KVM_X86_SEV_ES_VM || type == KVM_X86_SNP_VM);
 		to_kvm_sev_info(kvm)->need_init = true;
+
+		kvm->arch.has_private_mem = (type == KVM_X86_SNP_VM);
 	}
 
 	if (!pause_filter_count || !pause_filter_thresh)
@@ -5095,6 +5110,10 @@ static struct kvm_x86_ops svm_x86_ops __initdata = {
 	.vcpu_deliver_sipi_vector = svm_vcpu_deliver_sipi_vector,
 	.vcpu_get_apicv_inhibit_reasons = avic_vcpu_get_apicv_inhibit_reasons,
 	.alloc_apic_backing_page = svm_alloc_apic_backing_page,
+
+	.gmem_prepare = sev_gmem_prepare,
+	.gmem_invalidate = sev_gmem_invalidate,
+	.private_max_mapping_level = sev_private_max_mapping_level,
 };
 
 /*
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index 0f1472690b59..d2397b98bbf0 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -94,6 +94,7 @@ struct kvm_sev_info {
 	struct list_head mirror_entry; /* Use as a list entry of mirrors */
 	struct misc_cg *misc_cg; /* For misc cgroup accounting */
 	atomic_t migration_in_progress;
+	void *snp_context;      /* SNP guest context page */
 };
 
 struct kvm_svm {
@@ -209,6 +210,18 @@ struct vcpu_sev_es_state {
 	u32 ghcb_sa_len;
 	bool ghcb_sa_sync;
 	bool ghcb_sa_free;
+
+	/* SNP Page-State-Change buffer entries currently being processed */
+	u16 psc_idx;
+	u16 psc_inflight;
+	bool psc_2m;
+
+	u64 ghcb_registered_gpa;
+
+	struct mutex snp_vmsa_mutex; /* Used to handle concurrent updates of VMSA. */
+	gpa_t snp_vmsa_gpa;
+	bool snp_ap_waiting_for_reset;
+	bool snp_has_guest_vmsa;
 };
 
 struct vcpu_svm {
@@ -350,6 +363,23 @@ static __always_inline bool sev_es_guest(struct kvm *kvm)
 #endif
 }
 
+static __always_inline bool sev_snp_guest(struct kvm *kvm)
+{
+#ifdef CONFIG_KVM_AMD_SEV
+	struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
+
+	return (sev->vmsa_features & SVM_SEV_FEAT_SNP_ACTIVE) &&
+	       !WARN_ON_ONCE(!sev_es_guest(kvm));
+#else
+	return false;
+#endif
+}
+
+static inline bool ghcb_gpa_is_registered(struct vcpu_svm *svm, u64 val)
+{
+	return svm->sev_es.ghcb_registered_gpa == val;
+}
+
 static inline void vmcb_mark_all_dirty(struct vmcb *vmcb)
 {
 	vmcb->control.clean = 0;
@@ -705,6 +735,11 @@ void sev_hardware_unsetup(void);
 int sev_cpu_init(struct svm_cpu_data *sd);
 int sev_dev_get_attr(u32 group, u64 attr, u64 *val);
 extern unsigned int max_sev_asid;
+void sev_handle_rmp_fault(struct kvm_vcpu *vcpu, gpa_t gpa, u64 error_code);
+void sev_snp_init_protected_guest_state(struct kvm_vcpu *vcpu);
+int sev_gmem_prepare(struct kvm *kvm, kvm_pfn_t pfn, gfn_t gfn, int max_order);
+void sev_gmem_invalidate(kvm_pfn_t start, kvm_pfn_t end);
+int sev_private_max_mapping_level(struct kvm *kvm, kvm_pfn_t pfn);
 #else
 static inline struct page *snp_safe_alloc_page(struct kvm_vcpu *vcpu) {
 	return alloc_page(GFP_KERNEL_ACCOUNT | __GFP_ZERO);
@@ -718,6 +753,18 @@ static inline void sev_hardware_unsetup(void) {}
 static inline int sev_cpu_init(struct svm_cpu_data *sd) { return 0; }
 static inline int sev_dev_get_attr(u32 group, u64 attr, u64 *val) { return -ENXIO; }
 #define max_sev_asid 0
+static inline void sev_handle_rmp_fault(struct kvm_vcpu *vcpu, gpa_t gpa, u64 error_code) {}
+static inline void sev_snp_init_protected_guest_state(struct kvm_vcpu *vcpu) {}
+static inline int sev_gmem_prepare(struct kvm *kvm, kvm_pfn_t pfn, gfn_t gfn, int max_order)
+{
+	return 0;
+}
+static inline void sev_gmem_invalidate(kvm_pfn_t start, kvm_pfn_t end) {}
+static inline int sev_private_max_mapping_level(struct kvm *kvm, kvm_pfn_t pfn)
+{
+	return 0;
+}
+
 #endif
 
 /* vmenter.S */
diff --git a/arch/x86/kvm/trace.h b/arch/x86/kvm/trace.h
index e19fed438a67..10ad5d32fcc3 100644
--- a/arch/x86/kvm/trace.h
+++ b/arch/x86/kvm/trace.h
@@ -1834,6 +1834,37 @@ TRACE_EVENT(kvm_vmgexit_msr_protocol_exit,
 		  __entry->vcpu_id, __entry->ghcb_gpa, __entry->result)
 );
 
+/*
+ * Tracepoint for #NPFs due to RMP faults.
+ */
+TRACE_EVENT(kvm_rmp_fault,
+	TP_PROTO(struct kvm_vcpu *vcpu, u64 gpa, u64 pfn, u64 error_code,
+		 int rmp_level, int psmash_ret),
+	TP_ARGS(vcpu, gpa, pfn, error_code, rmp_level, psmash_ret),
+
+	TP_STRUCT__entry(
+		__field(unsigned int, vcpu_id)
+		__field(u64, gpa)
+		__field(u64, pfn)
+		__field(u64, error_code)
+		__field(int, rmp_level)
+		__field(int, psmash_ret)
+	),
+
+	TP_fast_assign(
+		__entry->vcpu_id	= vcpu->vcpu_id;
+		__entry->gpa		= gpa;
+		__entry->pfn		= pfn;
+		__entry->error_code	= error_code;
+		__entry->rmp_level	= rmp_level;
+		__entry->psmash_ret	= psmash_ret;
+	),
+
+	TP_printk("vcpu %u gpa %016llx pfn 0x%llx error_code 0x%llx rmp_level %d psmash_ret %d",
+		  __entry->vcpu_id, __entry->gpa, __entry->pfn,
+		  __entry->error_code, __entry->rmp_level, __entry->psmash_ret)
+);
+
 #endif /* _TRACE_KVM_H */
 
 #undef TRACE_INCLUDE_PATH
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 8c9e4281d978..fa064864ad2c 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -10930,6 +10930,14 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
 
 		if (kvm_check_request(KVM_REQ_UPDATE_CPU_DIRTY_LOGGING, vcpu))
 			static_call(kvm_x86_update_cpu_dirty_logging)(vcpu);
+
+		if (kvm_check_request(KVM_REQ_UPDATE_PROTECTED_GUEST_STATE, vcpu)) {
+			kvm_vcpu_reset(vcpu, true);
+			if (vcpu->arch.mp_state != KVM_MP_STATE_RUNNABLE) {
+				r = 1;
+				goto out;
+			}
+		}
 	}
 
 	if (kvm_check_request(KVM_REQ_EVENT, vcpu) || req_int_win ||
@@ -13137,6 +13145,9 @@ static inline bool kvm_vcpu_has_events(struct kvm_vcpu *vcpu)
 	if (kvm_test_request(KVM_REQ_PMI, vcpu))
 		return true;
 
+	if (kvm_test_request(KVM_REQ_UPDATE_PROTECTED_GUEST_STATE, vcpu))
+		return true;
+
 	if (kvm_arch_interrupt_allowed(vcpu) &&
 	    (kvm_cpu_has_interrupt(vcpu) ||
 	    kvm_guest_apic_has_interrupt(vcpu)))
@@ -13590,6 +13601,24 @@ bool kvm_arch_no_poll(struct kvm_vcpu *vcpu)
 }
 EXPORT_SYMBOL_GPL(kvm_arch_no_poll);
 
+#ifdef CONFIG_HAVE_KVM_GMEM_PREPARE
+bool kvm_arch_gmem_prepare_needed(struct kvm *kvm)
+{
+	return kvm->arch.vm_type == KVM_X86_SNP_VM;
+}
+
+int kvm_arch_gmem_prepare(struct kvm *kvm, gfn_t gfn, kvm_pfn_t pfn, int max_order)
+{
+	return static_call(kvm_x86_gmem_prepare)(kvm, pfn, gfn, max_order);
+}
+#endif
+
+#ifdef CONFIG_HAVE_KVM_GMEM_INVALIDATE
+void kvm_arch_gmem_invalidate(kvm_pfn_t start, kvm_pfn_t end)
+{
+	static_call_cond(kvm_x86_gmem_invalidate)(start, end);
+}
+#endif
 
 int kvm_spec_ctrl_test_value(u64 value)
 {
@@ -13975,6 +14004,7 @@ EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_vmgexit_enter);
 EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_vmgexit_exit);
 EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_vmgexit_msr_protocol_enter);
 EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_vmgexit_msr_protocol_exit);
+EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_rmp_fault);
 
 static int __init kvm_x86_init(void)
 {
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 692c01e41a18..7b57878c8c18 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -2441,4 +2441,40 @@ static inline int kvm_gmem_get_pfn(struct kvm *kvm,
 }
 #endif /* CONFIG_KVM_PRIVATE_MEM */
 
+#ifdef CONFIG_HAVE_KVM_GMEM_PREPARE
+int kvm_arch_gmem_prepare(struct kvm *kvm, gfn_t gfn, kvm_pfn_t pfn, int max_order);
+bool kvm_arch_gmem_prepare_needed(struct kvm *kvm);
+#endif
+
+/**
+ * kvm_gmem_populate() - Populate/prepare a GPA range with guest data
+ *
+ * @kvm: KVM instance
+ * @gfn: starting GFN to be populated
+ * @src: userspace-provided buffer containing data to copy into GFN range
+ *       (passed to @post_populate, and incremented on each iteration
+ *       if not NULL)
+ * @npages: number of pages to copy from userspace-buffer
+ * @post_populate: callback to issue for each gmem page that backs the GPA
+ *                 range
+ * @opaque: opaque data to pass to @post_populate callback
+ *
+ * This is primarily intended for cases where a gmem-backed GPA range needs
+ * to be initialized with userspace-provided data prior to being mapped into
+ * the guest as a private page. This should be called with the slots->lock
+ * held so that caller-enforced invariants regarding the expected memory
+ * attributes of the GPA range do not race with KVM_SET_MEMORY_ATTRIBUTES.
+ *
+ * Returns the number of pages that were populated.
+ */
+typedef int (*kvm_gmem_populate_cb)(struct kvm *kvm, gfn_t gfn, kvm_pfn_t pfn,
+				    void __user *src, int order, void *opaque);
+
+long kvm_gmem_populate(struct kvm *kvm, gfn_t gfn, void __user *src, long npages,
+		       kvm_gmem_populate_cb post_populate, void *opaque);
+
+#ifdef CONFIG_HAVE_KVM_GMEM_INVALIDATE
+void kvm_arch_gmem_invalidate(kvm_pfn_t start, kvm_pfn_t end);
+#endif
+
 #endif
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index ee633712bba0..ce7bac8f81da 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -209,6 +209,7 @@ enum mapping_flags {
 	AS_STABLE_WRITES,	/* must wait for writeback before modifying
 				   folio contents */
 	AS_UNMOVABLE,		/* The mapping cannot be moved, ever */
+	AS_INACCESSIBLE,	/* Do not attempt direct R/W access to the mapping */
 };
 
 /**
diff --git a/include/linux/psp-sev.h b/include/linux/psp-sev.h
index 3705c2044fc0..903ddfea8585 100644
--- a/include/linux/psp-sev.h
+++ b/include/linux/psp-sev.h
@@ -658,6 +658,7 @@ struct sev_data_snp_launch_update {
  * @id_auth_paddr: system physical address of ID block authentication structure
  * @id_block_en: indicates whether ID block is present
  * @auth_key_en: indicates whether author key is present in authentication structure
+ * @vcek_disabled: indicates whether use of VCEK is allowed for attestation reports
  * @rsvd: reserved
  * @host_data: host-supplied data for guest, not interpreted by firmware
  */
@@ -667,7 +668,8 @@ struct sev_data_snp_launch_finish {
 	u64 id_auth_paddr;
 	u8 id_block_en:1;
 	u8 auth_key_en:1;
-	u64 rsvd:62;
+	u8 vcek_disabled:1;
+	u64 rsvd:61;
 	u8 host_data[32];
 } __packed;
 
diff --git a/mm/truncate.c b/mm/truncate.c
index e99085bf3d34..60388935086d 100644
--- a/mm/truncate.c
+++ b/mm/truncate.c
@@ -233,7 +233,8 @@ bool truncate_inode_partial_folio(struct folio *folio, loff_t start, loff_t end)
 	 * doing a complex calculation here, and then doing the zeroing
 	 * anyway if the page split fails.
 	 */
-	folio_zero_range(folio, offset, length);
+	if (!(folio->mapping->flags & AS_INACCESSIBLE))
+		folio_zero_range(folio, offset, length);
 
 	if (folio_has_private(folio))
 		folio_invalidate(folio, offset, length);
diff --git a/virt/kvm/Kconfig b/virt/kvm/Kconfig
index 29b73eedfe74..754c6c923427 100644
--- a/virt/kvm/Kconfig
+++ b/virt/kvm/Kconfig
@@ -109,3 +109,11 @@ config KVM_GENERIC_PRIVATE_MEM
        select KVM_GENERIC_MEMORY_ATTRIBUTES
        select KVM_PRIVATE_MEM
        bool
+
+config HAVE_KVM_GMEM_PREPARE
+       bool
+       depends on KVM_PRIVATE_MEM
+
+config HAVE_KVM_GMEM_INVALIDATE
+       bool
+       depends on KVM_PRIVATE_MEM
diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c
index 0f4e0cf4f158..9714add38852 100644
--- a/virt/kvm/guest_memfd.c
+++ b/virt/kvm/guest_memfd.c
@@ -13,14 +13,50 @@ struct kvm_gmem {
 	struct list_head entry;
 };
 
-static struct folio *kvm_gmem_get_folio(struct inode *inode, pgoff_t index)
+static int kvm_gmem_prepare_folio(struct inode *inode, pgoff_t index, struct folio *folio)
+{
+#ifdef CONFIG_HAVE_KVM_GMEM_PREPARE
+	struct list_head *gmem_list = &inode->i_mapping->i_private_list;
+	struct kvm_gmem *gmem;
+
+	list_for_each_entry(gmem, gmem_list, entry) {
+		struct kvm_memory_slot *slot;
+		struct kvm *kvm = gmem->kvm;
+		struct page *page;
+		kvm_pfn_t pfn;
+		gfn_t gfn;
+		int rc;
+
+		if (!kvm_arch_gmem_prepare_needed(kvm))
+			continue;
+
+		slot = xa_load(&gmem->bindings, index);
+		if (!slot)
+			continue;
+
+		page = folio_file_page(folio, index);
+		pfn = page_to_pfn(page);
+		gfn = slot->base_gfn + index - slot->gmem.pgoff;
+		rc = kvm_arch_gmem_prepare(kvm, gfn, pfn, compound_order(compound_head(page)));
+		if (rc) {
+			pr_warn_ratelimited("gmem: Failed to prepare folio for index %lx GFN %llx PFN %llx error %d.\n",
+					    index, gfn, pfn, rc);
+			return rc;
+		}
+	}
+
+#endif
+	return 0;
+}
+
+static struct folio *kvm_gmem_get_folio(struct inode *inode, pgoff_t index, bool prepare)
 {
 	struct folio *folio;
 
 	/* TODO: Support huge pages. */
 	folio = filemap_grab_folio(inode->i_mapping, index);
-	if (IS_ERR_OR_NULL(folio))
-		return NULL;
+	if (IS_ERR(folio))
+		return folio;
 
 	/*
 	 * Use the up-to-date flag to track whether or not the memory has been
@@ -41,6 +77,15 @@ static struct folio *kvm_gmem_get_folio(struct inode *inode, pgoff_t index)
 		folio_mark_uptodate(folio);
 	}
 
+	if (prepare) {
+		int r =	kvm_gmem_prepare_folio(inode, index, folio);
+		if (r < 0) {
+			folio_unlock(folio);
+			folio_put(folio);
+			return ERR_PTR(r);
+		}
+	}
+
 	/*
 	 * Ignore accessed, referenced, and dirty flags.  The memory is
 	 * unevictable and there is no storage to write back to.
@@ -145,9 +190,9 @@ static long kvm_gmem_allocate(struct inode *inode, loff_t offset, loff_t len)
 			break;
 		}
 
-		folio = kvm_gmem_get_folio(inode, index);
-		if (!folio) {
-			r = -ENOMEM;
+		folio = kvm_gmem_get_folio(inode, index, true);
+		if (IS_ERR(folio)) {
+			r = PTR_ERR(folio);
 			break;
 		}
 
@@ -298,10 +343,24 @@ static int kvm_gmem_error_folio(struct address_space *mapping, struct folio *fol
 	return MF_DELAYED;
 }
 
+#ifdef CONFIG_HAVE_KVM_GMEM_INVALIDATE
+static void kvm_gmem_free_folio(struct folio *folio)
+{
+	struct page *page = folio_page(folio, 0);
+	kvm_pfn_t pfn = page_to_pfn(page);
+	int order = folio_order(folio);
+
+	kvm_arch_gmem_invalidate(pfn, pfn + (1ul << order));
+}
+#endif
+
 static const struct address_space_operations kvm_gmem_aops = {
 	.dirty_folio = noop_dirty_folio,
 	.migrate_folio	= kvm_gmem_migrate_folio,
 	.error_remove_folio = kvm_gmem_error_folio,
+#ifdef CONFIG_HAVE_KVM_GMEM_INVALIDATE
+	.free_folio = kvm_gmem_free_folio,
+#endif
 };
 
 static int kvm_gmem_getattr(struct mnt_idmap *idmap, const struct path *path,
@@ -357,6 +416,7 @@ static int __kvm_gmem_create(struct kvm *kvm, loff_t size, u64 flags)
 	inode->i_private = (void *)(unsigned long)flags;
 	inode->i_op = &kvm_gmem_iops;
 	inode->i_mapping->a_ops = &kvm_gmem_aops;
+	inode->i_mapping->flags |= AS_INACCESSIBLE;
 	inode->i_mode |= S_IFREG;
 	inode->i_size = size;
 	mapping_set_gfp_mask(inode->i_mapping, GFP_HIGHUSER);
@@ -482,32 +542,29 @@ void kvm_gmem_unbind(struct kvm_memory_slot *slot)
 	fput(file);
 }
 
-int kvm_gmem_get_pfn(struct kvm *kvm, struct kvm_memory_slot *slot,
-		     gfn_t gfn, kvm_pfn_t *pfn, int *max_order)
+static int __kvm_gmem_get_pfn(struct file *file, struct kvm_memory_slot *slot,
+		       gfn_t gfn, kvm_pfn_t *pfn, int *max_order, bool prepare)
 {
 	pgoff_t index = gfn - slot->base_gfn + slot->gmem.pgoff;
-	struct kvm_gmem *gmem;
+	struct kvm_gmem *gmem = file->private_data;
 	struct folio *folio;
 	struct page *page;
-	struct file *file;
 	int r;
 
-	file = kvm_gmem_get_file(slot);
-	if (!file)
+	if (file != slot->gmem.file) {
+		WARN_ON_ONCE(slot->gmem.file);
 		return -EFAULT;
+	}
 
 	gmem = file->private_data;
-
-	if (WARN_ON_ONCE(xa_load(&gmem->bindings, index) != slot)) {
-		r = -EIO;
-		goto out_fput;
+	if (xa_load(&gmem->bindings, index) != slot) {
+		WARN_ON_ONCE(xa_load(&gmem->bindings, index));
+		return -EIO;
 	}
 
-	folio = kvm_gmem_get_folio(file_inode(file), index);
-	if (!folio) {
-		r = -ENOMEM;
-		goto out_fput;
-	}
+	folio = kvm_gmem_get_folio(file_inode(file), index, prepare);
+	if (IS_ERR(folio))
+		return PTR_ERR(folio);
 
 	if (folio_test_hwpoison(folio)) {
 		r = -EHWPOISON;
@@ -524,9 +581,73 @@ int kvm_gmem_get_pfn(struct kvm *kvm, struct kvm_memory_slot *slot,
 
 out_unlock:
 	folio_unlock(folio);
-out_fput:
-	fput(file);
 
 	return r;
 }
+
+int kvm_gmem_get_pfn(struct kvm *kvm, struct kvm_memory_slot *slot,
+		     gfn_t gfn, kvm_pfn_t *pfn, int *max_order)
+{
+	struct file *file = kvm_gmem_get_file(slot);
+	int r;
+
+	if (!file)
+		return -EFAULT;
+
+	r = __kvm_gmem_get_pfn(file, slot, gfn, pfn, max_order, true);
+	fput(file);
+	return r;
+}
 EXPORT_SYMBOL_GPL(kvm_gmem_get_pfn);
+
+long kvm_gmem_populate(struct kvm *kvm, gfn_t start_gfn, void __user *src, long npages,
+		       kvm_gmem_populate_cb post_populate, void *opaque)
+{
+	struct file *file;
+	struct kvm_memory_slot *slot;
+	void __user *p;
+
+	int ret = 0, max_order;
+	long i;
+
+	lockdep_assert_held(&kvm->slots_lock);
+	if (npages < 0)
+		return -EINVAL;
+
+	slot = gfn_to_memslot(kvm, start_gfn);
+	if (!kvm_slot_can_be_private(slot))
+		return -EINVAL;
+
+	file = kvm_gmem_get_file(slot);
+	if (!file)
+		return -EFAULT;
+
+	filemap_invalidate_lock(file->f_mapping);
+
+	npages = min_t(ulong, slot->npages - (start_gfn - slot->base_gfn), npages);
+	for (i = 0; i < npages; i += (1 << max_order)) {
+		gfn_t gfn = start_gfn + i;
+		kvm_pfn_t pfn;
+
+		ret = __kvm_gmem_get_pfn(file, slot, gfn, &pfn, &max_order, false);
+		if (ret)
+			break;
+
+		if (!IS_ALIGNED(gfn, (1 << max_order)) ||
+		    (npages - i) < (1 << max_order))
+			max_order = 0;
+
+		p = src ? src + i * PAGE_SIZE : NULL;
+		ret = post_populate(kvm, gfn, pfn, p, max_order, opaque);
+
+		put_page(pfn_to_page(pfn));
+		if (ret)
+			break;
+	}
+
+	filemap_invalidate_unlock(file->f_mapping);
+
+	fput(file);
+	return ret && !i ? ret : i;
+}
+EXPORT_SYMBOL_GPL(kvm_gmem_populate);