From 1ca5614b84eed5904f65f143e0e7aaab0ac4c6b2 Mon Sep 17 00:00:00 2001 From: Brijesh Singh Date: Thu, 25 Jan 2024 22:11:13 -0600 Subject: crypto: ccp: Add support to initialize the AMD-SP for SEV-SNP Before SNP VMs can be launched, the platform must be appropriately configured and initialized via the SNP_INIT command. During the execution of SNP_INIT command, the firmware configures and enables SNP security policy enforcement in many system components. Some system components write to regions of memory reserved by early x86 firmware (e.g. UEFI). Other system components write to regions provided by the operation system, hypervisor, or x86 firmware. Such system components can only write to HV-fixed pages or Default pages. They will error when attempting to write to pages in other page states after SNP_INIT enables their SNP enforcement. Starting in SNP firmware v1.52, the SNP_INIT_EX command takes a list of system physical address ranges to convert into the HV-fixed page states during the RMP initialization. If INIT_RMP is 1, hypervisors should provide all system physical address ranges that the hypervisor will never assign to a guest until the next RMP re-initialization. For instance, the memory that UEFI reserves should be included in the range list. This allows system components that occasionally write to memory (e.g. logging to UEFI reserved regions) to not fail due to RMP initialization and SNP enablement. Note that SNP_INIT(_EX) must not be executed while non-SEV guests are executing, otherwise it is possible that the system could reset or hang. The psp_init_on_probe module parameter was added for SEV/SEV-ES support and the init_ex_path module parameter to allow for time for the necessary file system to be mounted/available. SNP_INIT(_EX) does not use the file associated with init_ex_path. So, to avoid running into issues where SNP_INIT(_EX) is called while there are other running guests, issue it during module probe regardless of the psp_init_on_probe setting, but maintain the previous deferrable handling for SEV/SEV-ES initialization. [ mdr: Squash in psp_init_on_probe changes from Tom, reduce proliferation of 'probe' function parameter where possible. bp: Fix 32-bit allmodconfig build. ] Signed-off-by: Brijesh Singh Co-developed-by: Ashish Kalra Signed-off-by: Ashish Kalra Co-developed-by: Jarkko Sakkinen Signed-off-by: Jarkko Sakkinen Signed-off-by: Tom Lendacky Signed-off-by: Michael Roth Signed-off-by: Borislav Petkov (AMD) Link: https://lore.kernel.org/r/20240126041126.1927228-14-michael.roth@amd.com --- arch/x86/kvm/svm/sev.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'arch/x86/kvm') diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c index f760106c31f8..564091f386f7 100644 --- a/arch/x86/kvm/svm/sev.c +++ b/arch/x86/kvm/svm/sev.c @@ -246,6 +246,7 @@ static void sev_unbind_asid(struct kvm *kvm, unsigned int handle) static int sev_guest_init(struct kvm *kvm, struct kvm_sev_cmd *argp) { struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info; + struct sev_platform_init_args init_args = {0}; int asid, ret; if (kvm->created_vcpus) @@ -262,7 +263,8 @@ static int sev_guest_init(struct kvm *kvm, struct kvm_sev_cmd *argp) goto e_no_asid; sev->asid = asid; - ret = sev_platform_init(&argp->error); + init_args.probe = false; + ret = sev_platform_init(&init_args); if (ret) goto e_free; @@ -274,6 +276,7 @@ static int sev_guest_init(struct kvm *kvm, struct kvm_sev_cmd *argp) return 0; e_free: + argp->error = init_args.error; sev_asid_free(sev); sev->asid = 0; e_no_asid: -- cgit v1.2.3 From 75253db41a467ab7983b62616b25ff083c28803a Mon Sep 17 00:00:00 2001 From: Brijesh Singh Date: Thu, 25 Jan 2024 22:11:21 -0600 Subject: KVM: SEV: Make AVIC backing, VMSA and VMCB memory allocation SNP safe Implement a workaround for an SNP erratum where the CPU will incorrectly signal an RMP violation #PF if a hugepage (2MB or 1GB) collides with the RMP entry of a VMCB, VMSA or AVIC backing page. When SEV-SNP is globally enabled, the CPU marks the VMCB, VMSA, and AVIC backing pages as "in-use" via a reserved bit in the corresponding RMP entry after a successful VMRUN. This is done for _all_ VMs, not just SNP-Active VMs. If the hypervisor accesses an in-use page through a writable translation, the CPU will throw an RMP violation #PF. On early SNP hardware, if an in-use page is 2MB-aligned and software accesses any part of the associated 2MB region with a hugepage, the CPU will incorrectly treat the entire 2MB region as in-use and signal a an RMP violation #PF. To avoid this, the recommendation is to not use a 2MB-aligned page for the VMCB, VMSA or AVIC pages. Add a generic allocator that will ensure that the page returned is not 2MB-aligned and is safe to be used when SEV-SNP is enabled. Also implement similar handling for the VMCB/VMSA pages of nested guests. [ mdr: Squash in nested guest handling from Ashish, commit msg fixups. ] Reported-by: Alper Gun # for nested VMSA case Signed-off-by: Brijesh Singh Co-developed-by: Marc Orr Signed-off-by: Marc Orr Co-developed-by: Ashish Kalra Signed-off-by: Ashish Kalra Signed-off-by: Michael Roth Signed-off-by: Borislav Petkov (AMD) Acked-by: Vlastimil Babka Acked-by: Paolo Bonzini Link: https://lore.kernel.org/r/20240126041126.1927228-22-michael.roth@amd.com --- arch/x86/include/asm/kvm-x86-ops.h | 1 + arch/x86/include/asm/kvm_host.h | 1 + arch/x86/kvm/lapic.c | 5 ++++- arch/x86/kvm/svm/nested.c | 2 +- arch/x86/kvm/svm/sev.c | 32 ++++++++++++++++++++++++++++++++ arch/x86/kvm/svm/svm.c | 17 ++++++++++++++--- arch/x86/kvm/svm/svm.h | 1 + 7 files changed, 54 insertions(+), 5 deletions(-) (limited to 'arch/x86/kvm') diff --git a/arch/x86/include/asm/kvm-x86-ops.h b/arch/x86/include/asm/kvm-x86-ops.h index 378ed944b849..ab24ce207988 100644 --- a/arch/x86/include/asm/kvm-x86-ops.h +++ b/arch/x86/include/asm/kvm-x86-ops.h @@ -138,6 +138,7 @@ KVM_X86_OP(complete_emulated_msr) 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) #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 b5b2d0fde579..5c12af29fd9b 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -1794,6 +1794,7 @@ struct kvm_x86_ops { unsigned long (*vcpu_get_apicv_inhibit_reasons)(struct kvm_vcpu *vcpu); gva_t (*get_untagged_addr)(struct kvm_vcpu *vcpu, gva_t gva, unsigned int flags); + void *(*alloc_apic_backing_page)(struct kvm_vcpu *vcpu); }; struct kvm_x86_nested_ops { diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c index 3242f3da2457..1edf93ee3395 100644 --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -2815,7 +2815,10 @@ int kvm_create_lapic(struct kvm_vcpu *vcpu, int timer_advance_ns) vcpu->arch.apic = apic; - apic->regs = (void *)get_zeroed_page(GFP_KERNEL_ACCOUNT); + if (kvm_x86_ops.alloc_apic_backing_page) + apic->regs = static_call(kvm_x86_alloc_apic_backing_page)(vcpu); + else + apic->regs = (void *)get_zeroed_page(GFP_KERNEL_ACCOUNT); if (!apic->regs) { printk(KERN_ERR "malloc apic regs error for vcpu %x\n", vcpu->vcpu_id); diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c index dee62362a360..55b9a6d96bcf 100644 --- a/arch/x86/kvm/svm/nested.c +++ b/arch/x86/kvm/svm/nested.c @@ -1181,7 +1181,7 @@ int svm_allocate_nested(struct vcpu_svm *svm) if (svm->nested.initialized) return 0; - vmcb02_page = alloc_page(GFP_KERNEL_ACCOUNT | __GFP_ZERO); + vmcb02_page = snp_safe_alloc_page(&svm->vcpu); if (!vmcb02_page) return -ENOMEM; svm->nested.vmcb02.ptr = page_address(vmcb02_page); diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c index 564091f386f7..f99435b6648f 100644 --- a/arch/x86/kvm/svm/sev.c +++ b/arch/x86/kvm/svm/sev.c @@ -3163,3 +3163,35 @@ void sev_vcpu_deliver_sipi_vector(struct kvm_vcpu *vcpu, u8 vector) ghcb_set_sw_exit_info_2(svm->sev_es.ghcb, 1); } + +struct page *snp_safe_alloc_page(struct kvm_vcpu *vcpu) +{ + unsigned long pfn; + struct page *p; + + if (!cpu_feature_enabled(X86_FEATURE_SEV_SNP)) + return alloc_page(GFP_KERNEL_ACCOUNT | __GFP_ZERO); + + /* + * Allocate an SNP-safe page to workaround the SNP erratum where + * the CPU will incorrectly signal an RMP violation #PF if a + * hugepage (2MB or 1GB) collides with the RMP entry of a + * 2MB-aligned VMCB, VMSA, or AVIC backing page. + * + * Allocate one extra page, choose a page which is not + * 2MB-aligned, and free the other. + */ + p = alloc_pages(GFP_KERNEL_ACCOUNT | __GFP_ZERO, 1); + if (!p) + return NULL; + + split_page(p, 1); + + pfn = page_to_pfn(p); + if (IS_ALIGNED(pfn, PTRS_PER_PMD)) + __free_page(p++); + else + __free_page(p + 1); + + return p; +} diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index e90b429c84f1..8284105bf704 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -703,7 +703,7 @@ static int svm_cpu_init(int cpu) int ret = -ENOMEM; memset(sd, 0, sizeof(struct svm_cpu_data)); - sd->save_area = alloc_page(GFP_KERNEL | __GFP_ZERO); + sd->save_area = snp_safe_alloc_page(NULL); if (!sd->save_area) return ret; @@ -1421,7 +1421,7 @@ static int svm_vcpu_create(struct kvm_vcpu *vcpu) svm = to_svm(vcpu); err = -ENOMEM; - vmcb01_page = alloc_page(GFP_KERNEL_ACCOUNT | __GFP_ZERO); + vmcb01_page = snp_safe_alloc_page(vcpu); if (!vmcb01_page) goto out; @@ -1430,7 +1430,7 @@ static int svm_vcpu_create(struct kvm_vcpu *vcpu) * SEV-ES guests require a separate VMSA page used to contain * the encrypted register state of the guest. */ - vmsa_page = alloc_page(GFP_KERNEL_ACCOUNT | __GFP_ZERO); + vmsa_page = snp_safe_alloc_page(vcpu); if (!vmsa_page) goto error_free_vmcb_page; @@ -4900,6 +4900,16 @@ static int svm_vm_init(struct kvm *kvm) return 0; } +static void *svm_alloc_apic_backing_page(struct kvm_vcpu *vcpu) +{ + struct page *page = snp_safe_alloc_page(vcpu); + + if (!page) + return NULL; + + return page_address(page); +} + static struct kvm_x86_ops svm_x86_ops __initdata = { .name = KBUILD_MODNAME, @@ -5031,6 +5041,7 @@ 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, }; /* diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h index 8ef95139cd24..7f1fbd874c45 100644 --- a/arch/x86/kvm/svm/svm.h +++ b/arch/x86/kvm/svm/svm.h @@ -694,6 +694,7 @@ void sev_es_vcpu_reset(struct vcpu_svm *svm); void sev_vcpu_deliver_sipi_vector(struct kvm_vcpu *vcpu, u8 vector); void sev_es_prepare_switch_to_guest(struct sev_es_save_area *hostsa); void sev_es_unmap_ghcb(struct vcpu_svm *svm); +struct page *snp_safe_alloc_page(struct kvm_vcpu *vcpu); /* vmenter.S */ -- cgit v1.2.3