18 files changed, 904 insertions, 235 deletions

diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile
index 6115274fe10f..19e1905dcbf6 100644
--- a/arch/x86/boot/compressed/Makefile
+++ b/arch/x86/boot/compressed/Makefile
@@ -101,8 +101,10 @@ ifdef CONFIG_X86_64
 endif
 
 vmlinux-objs-$(CONFIG_ACPI) += $(obj)/acpi.o
+vmlinux-objs-$(CONFIG_INTEL_TDX_GUEST) += $(obj)/tdx.o $(obj)/tdcall.o
 
 vmlinux-objs-$(CONFIG_EFI_MIXED) += $(obj)/efi_thunk_$(BITS).o
+vmlinux-objs-$(CONFIG_EFI) += $(obj)/efi.o
 efi-obj-$(CONFIG_EFI_STUB) = $(objtree)/drivers/firmware/efi/libstub/lib.a
 
 $(obj)/vmlinux: $(vmlinux-objs-y) $(efi-obj-y) FORCE
diff --git a/arch/x86/boot/compressed/acpi.c b/arch/x86/boot/compressed/acpi.c
index 8bcbcee54aa1..9caf89063e77 100644
--- a/arch/x86/boot/compressed/acpi.c
+++ b/arch/x86/boot/compressed/acpi.c
@@ -3,10 +3,9 @@
 #include "misc.h"
 #include "error.h"
 #include "../string.h"
+#include "efi.h"
 
 #include <linux/numa.h>
-#include <linux/efi.h>
-#include <asm/efi.h>
 
 /*
  * Longest parameter of 'acpi=' is 'copy_dsdt', plus an extra '\0'
@@ -20,153 +19,56 @@
  */
 struct mem_vector immovable_mem[MAX_NUMNODES*2];
 
-/*
- * Search EFI system tables for RSDP.  If both ACPI_20_TABLE_GUID and
- * ACPI_TABLE_GUID are found, take the former, which has more features.
- */
 static acpi_physical_address
-__efi_get_rsdp_addr(unsigned long config_tables, unsigned int nr_tables,
-		    bool efi_64)
+__efi_get_rsdp_addr(unsigned long cfg_tbl_pa, unsigned int cfg_tbl_len)
 {
-	acpi_physical_address rsdp_addr = 0;
-
 #ifdef CONFIG_EFI
-	int i;
-
-	/* Get EFI tables from systab. */
-	for (i = 0; i < nr_tables; i++) {
-		acpi_physical_address table;
-		efi_guid_t guid;
-
-		if (efi_64) {
-			efi_config_table_64_t *tbl = (efi_config_table_64_t *)config_tables + i;
-
-			guid  = tbl->guid;
-			table = tbl->table;
-
-			if (!IS_ENABLED(CONFIG_X86_64) && table >> 32) {
-				debug_putstr("Error getting RSDP address: EFI config table located above 4GB.\n");
-				return 0;
-			}
-		} else {
-			efi_config_table_32_t *tbl = (efi_config_table_32_t *)config_tables + i;
-
-			guid  = tbl->guid;
-			table = tbl->table;
-		}
+	unsigned long rsdp_addr;
+	int ret;
 
-		if (!(efi_guidcmp(guid, ACPI_TABLE_GUID)))
-			rsdp_addr = table;
-		else if (!(efi_guidcmp(guid, ACPI_20_TABLE_GUID)))
-			return table;
-	}
+	/*
+	 * Search EFI system tables for RSDP. Preferred is ACPI_20_TABLE_GUID to
+	 * ACPI_TABLE_GUID because it has more features.
+	 */
+	rsdp_addr = efi_find_vendor_table(boot_params, cfg_tbl_pa, cfg_tbl_len,
+					  ACPI_20_TABLE_GUID);
+	if (rsdp_addr)
+		return (acpi_physical_address)rsdp_addr;
+
+	/* No ACPI_20_TABLE_GUID found, fallback to ACPI_TABLE_GUID. */
+	rsdp_addr = efi_find_vendor_table(boot_params, cfg_tbl_pa, cfg_tbl_len,
+					  ACPI_TABLE_GUID);
+	if (rsdp_addr)
+		return (acpi_physical_address)rsdp_addr;
+
+	debug_putstr("Error getting RSDP address.\n");
 #endif
-	return rsdp_addr;
-}
-
-/* EFI/kexec support is 64-bit only. */
-#ifdef CONFIG_X86_64
-static struct efi_setup_data *get_kexec_setup_data_addr(void)
-{
-	struct setup_data *data;
-	u64 pa_data;
-
-	pa_data = boot_params->hdr.setup_data;
-	while (pa_data) {
-		data = (struct setup_data *)pa_data;
-		if (data->type == SETUP_EFI)
-			return (struct efi_setup_data *)(pa_data + sizeof(struct setup_data));
-
-		pa_data = data->next;
-	}
-	return NULL;
-}
-
-static acpi_physical_address kexec_get_rsdp_addr(void)
-{
-	efi_system_table_64_t *systab;
-	struct efi_setup_data *esd;
-	struct efi_info *ei;
-	char *sig;
-
-	esd = (struct efi_setup_data *)get_kexec_setup_data_addr();
-	if (!esd)
-		return 0;
-
-	if (!esd->tables) {
-		debug_putstr("Wrong kexec SETUP_EFI data.\n");
-		return 0;
-	}
-
-	ei = &boot_params->efi_info;
-	sig = (char *)&ei->efi_loader_signature;
-	if (strncmp(sig, EFI64_LOADER_SIGNATURE, 4)) {
-		debug_putstr("Wrong kexec EFI loader signature.\n");
-		return 0;
-	}
-
-	/* Get systab from boot params. */
-	systab = (efi_system_table_64_t *) (ei->efi_systab | ((__u64)ei->efi_systab_hi << 32));
-	if (!systab)
-		error("EFI system table not found in kexec boot_params.");
-
-	return __efi_get_rsdp_addr((unsigned long)esd->tables, systab->nr_tables, true);
+	return 0;
 }
-#else
-static acpi_physical_address kexec_get_rsdp_addr(void) { return 0; }
-#endif /* CONFIG_X86_64 */
 
 static acpi_physical_address efi_get_rsdp_addr(void)
 {
 #ifdef CONFIG_EFI
-	unsigned long systab, config_tables;
+	unsigned long cfg_tbl_pa = 0;
+	unsigned int cfg_tbl_len;
+	unsigned long systab_pa;
 	unsigned int nr_tables;
-	struct efi_info *ei;
-	bool efi_64;
-	char *sig;
-
-	ei = &boot_params->efi_info;
-	sig = (char *)&ei->efi_loader_signature;
-
-	if (!strncmp(sig, EFI64_LOADER_SIGNATURE, 4)) {
-		efi_64 = true;
-	} else if (!strncmp(sig, EFI32_LOADER_SIGNATURE, 4)) {
-		efi_64 = false;
-	} else {
-		debug_putstr("Wrong EFI loader signature.\n");
-		return 0;
-	}
+	enum efi_type et;
+	int ret;
 
-	/* Get systab from boot params. */
-#ifdef CONFIG_X86_64
-	systab = ei->efi_systab | ((__u64)ei->efi_systab_hi << 32);
-#else
-	if (ei->efi_systab_hi || ei->efi_memmap_hi) {
-		debug_putstr("Error getting RSDP address: EFI system table located above 4GB.\n");
+	et = efi_get_type(boot_params);
+	if (et == EFI_TYPE_NONE)
 		return 0;
-	}
-	systab = ei->efi_systab;
-#endif
-	if (!systab)
-		error("EFI system table not found.");
 
-	/* Handle EFI bitness properly */
-	if (efi_64) {
-		efi_system_table_64_t *stbl = (efi_system_table_64_t *)systab;
+	systab_pa = efi_get_system_table(boot_params);
+	if (!systab_pa)
+		error("EFI support advertised, but unable to locate system table.");
 
-		config_tables	= stbl->tables;
-		nr_tables	= stbl->nr_tables;
-	} else {
-		efi_system_table_32_t *stbl = (efi_system_table_32_t *)systab;
+	ret = efi_get_conf_table(boot_params, &cfg_tbl_pa, &cfg_tbl_len);
+	if (ret || !cfg_tbl_pa)
+		error("EFI config table not found.");
 
-		config_tables	= stbl->tables;
-		nr_tables	= stbl->nr_tables;
-	}
-
-	if (!config_tables)
-		error("EFI config tables not found.");
-
-	return __efi_get_rsdp_addr(config_tables, nr_tables, efi_64);
+	return __efi_get_rsdp_addr(cfg_tbl_pa, cfg_tbl_len);
 #else
 	return 0;
 #endif
@@ -256,14 +158,6 @@ acpi_physical_address get_rsdp_addr(void)
 
 	pa = boot_params->acpi_rsdp_addr;
 
-	/*
-	 * Try to get EFI data from setup_data. This can happen when we're a
-	 * kexec'ed kernel and kexec(1) has passed all the required EFI info to
-	 * us.
-	 */
-	if (!pa)
-		pa = kexec_get_rsdp_addr();
-
 	if (!pa)
 		pa = efi_get_rsdp_addr();
 
diff --git a/arch/x86/boot/compressed/early_serial_console.c b/arch/x86/boot/compressed/early_serial_console.c
index 261e81fb9582..70a8d1706d0f 100644
--- a/arch/x86/boot/compressed/early_serial_console.c
+++ b/arch/x86/boot/compressed/early_serial_console.c
@@ -1,5 +1,6 @@
 #include "misc.h"
 
-int early_serial_base;
+/* This might be accessed before .bss is cleared, so use .data instead. */
+int early_serial_base __section(".data");
 
 #include "../early_serial_console.c"
diff --git a/arch/x86/boot/compressed/efi.c b/arch/x86/boot/compressed/efi.c
new file mode 100644
index 000000000000..6edd034b0b30
--- /dev/null
+++ b/arch/x86/boot/compressed/efi.c
@@ -0,0 +1,234 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Helpers for early access to EFI configuration table.
+ *
+ * Originally derived from arch/x86/boot/compressed/acpi.c
+ */
+
+#include "misc.h"
+
+/**
+ * efi_get_type - Given a pointer to boot_params, determine the type of EFI environment.
+ *
+ * @bp:         pointer to boot_params
+ *
+ * Return: EFI_TYPE_{32,64} for valid EFI environments, EFI_TYPE_NONE otherwise.
+ */
+enum efi_type efi_get_type(struct boot_params *bp)
+{
+	struct efi_info *ei;
+	enum efi_type et;
+	const char *sig;
+
+	ei = &bp->efi_info;
+	sig = (char *)&ei->efi_loader_signature;
+
+	if (!strncmp(sig, EFI64_LOADER_SIGNATURE, 4)) {
+		et = EFI_TYPE_64;
+	} else if (!strncmp(sig, EFI32_LOADER_SIGNATURE, 4)) {
+		et = EFI_TYPE_32;
+	} else {
+		debug_putstr("No EFI environment detected.\n");
+		et = EFI_TYPE_NONE;
+	}
+
+#ifndef CONFIG_X86_64
+	/*
+	 * Existing callers like acpi.c treat this case as an indicator to
+	 * fall-through to non-EFI, rather than an error, so maintain that
+	 * functionality here as well.
+	 */
+	if (ei->efi_systab_hi || ei->efi_memmap_hi) {
+		debug_putstr("EFI system table is located above 4GB and cannot be accessed.\n");
+		et = EFI_TYPE_NONE;
+	}
+#endif
+
+	return et;
+}
+
+/**
+ * efi_get_system_table - Given a pointer to boot_params, retrieve the physical address
+ *                        of the EFI system table.
+ *
+ * @bp:         pointer to boot_params
+ *
+ * Return: EFI system table address on success. On error, return 0.
+ */
+unsigned long efi_get_system_table(struct boot_params *bp)
+{
+	unsigned long sys_tbl_pa;
+	struct efi_info *ei;
+	enum efi_type et;
+
+	/* Get systab from boot params. */
+	ei = &bp->efi_info;
+#ifdef CONFIG_X86_64
+	sys_tbl_pa = ei->efi_systab | ((__u64)ei->efi_systab_hi << 32);
+#else
+	sys_tbl_pa = ei->efi_systab;
+#endif
+	if (!sys_tbl_pa) {
+		debug_putstr("EFI system table not found.");
+		return 0;
+	}
+
+	return sys_tbl_pa;
+}
+
+/*
+ * EFI config table address changes to virtual address after boot, which may
+ * not be accessible for the kexec'd kernel. To address this, kexec provides
+ * the initial physical address via a struct setup_data entry, which is
+ * checked for here, along with some sanity checks.
+ */
+static struct efi_setup_data *get_kexec_setup_data(struct boot_params *bp,
+						   enum efi_type et)
+{
+#ifdef CONFIG_X86_64
+	struct efi_setup_data *esd = NULL;
+	struct setup_data *data;
+	u64 pa_data;
+
+	pa_data = bp->hdr.setup_data;
+	while (pa_data) {
+		data = (struct setup_data *)pa_data;
+		if (data->type == SETUP_EFI) {
+			esd = (struct efi_setup_data *)(pa_data + sizeof(struct setup_data));
+			break;
+		}
+
+		pa_data = data->next;
+	}
+
+	/*
+	 * Original ACPI code falls back to attempting normal EFI boot in these
+	 * cases, so maintain existing behavior by indicating non-kexec
+	 * environment to the caller, but print them for debugging.
+	 */
+	if (esd && !esd->tables) {
+		debug_putstr("kexec EFI environment missing valid configuration table.\n");
+		return NULL;
+	}
+
+	return esd;
+#endif
+	return NULL;
+}
+
+/**
+ * efi_get_conf_table - Given a pointer to boot_params, locate and return the physical
+ *                      address of EFI configuration table.
+ *
+ * @bp:                 pointer to boot_params
+ * @cfg_tbl_pa:         location to store physical address of config table
+ * @cfg_tbl_len:        location to store number of config table entries
+ *
+ * Return: 0 on success. On error, return params are left unchanged.
+ */
+int efi_get_conf_table(struct boot_params *bp, unsigned long *cfg_tbl_pa,
+		       unsigned int *cfg_tbl_len)
+{
+	unsigned long sys_tbl_pa;
+	enum efi_type et;
+	int ret;
+
+	if (!cfg_tbl_pa || !cfg_tbl_len)
+		return -EINVAL;
+
+	sys_tbl_pa = efi_get_system_table(bp);
+	if (!sys_tbl_pa)
+		return -EINVAL;
+
+	/* Handle EFI bitness properly */
+	et = efi_get_type(bp);
+	if (et == EFI_TYPE_64) {
+		efi_system_table_64_t *stbl = (efi_system_table_64_t *)sys_tbl_pa;
+		struct efi_setup_data *esd;
+
+		/* kexec provides an alternative EFI conf table, check for it. */
+		esd = get_kexec_setup_data(bp, et);
+
+		*cfg_tbl_pa = esd ? esd->tables : stbl->tables;
+		*cfg_tbl_len = stbl->nr_tables;
+	} else if (et == EFI_TYPE_32) {
+		efi_system_table_32_t *stbl = (efi_system_table_32_t *)sys_tbl_pa;
+
+		*cfg_tbl_pa = stbl->tables;
+		*cfg_tbl_len = stbl->nr_tables;
+	} else {
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+/* Get vendor table address/guid from EFI config table at the given index */
+static int get_vendor_table(void *cfg_tbl, unsigned int idx,
+			    unsigned long *vendor_tbl_pa,
+			    efi_guid_t *vendor_tbl_guid,
+			    enum efi_type et)
+{
+	if (et == EFI_TYPE_64) {
+		efi_config_table_64_t *tbl_entry = (efi_config_table_64_t *)cfg_tbl + idx;
+
+		if (!IS_ENABLED(CONFIG_X86_64) && tbl_entry->table >> 32) {
+			debug_putstr("Error: EFI config table entry located above 4GB.\n");
+			return -EINVAL;
+		}
+
+		*vendor_tbl_pa = tbl_entry->table;
+		*vendor_tbl_guid = tbl_entry->guid;
+
+	} else if (et == EFI_TYPE_32) {
+		efi_config_table_32_t *tbl_entry = (efi_config_table_32_t *)cfg_tbl + idx;
+
+		*vendor_tbl_pa = tbl_entry->table;
+		*vendor_tbl_guid = tbl_entry->guid;
+	} else {
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+/**
+ * efi_find_vendor_table - Given EFI config table, search it for the physical
+ *                         address of the vendor table associated with GUID.
+ *
+ * @bp:                pointer to boot_params
+ * @cfg_tbl_pa:        pointer to EFI configuration table
+ * @cfg_tbl_len:       number of entries in EFI configuration table
+ * @guid:              GUID of vendor table
+ *
+ * Return: vendor table address on success. On error, return 0.
+ */
+unsigned long efi_find_vendor_table(struct boot_params *bp,
+				    unsigned long cfg_tbl_pa,
+				    unsigned int cfg_tbl_len,
+				    efi_guid_t guid)
+{
+	enum efi_type et;
+	unsigned int i;
+
+	et = efi_get_type(bp);
+	if (et == EFI_TYPE_NONE)
+		return 0;
+
+	for (i = 0; i < cfg_tbl_len; i++) {
+		unsigned long vendor_tbl_pa;
+		efi_guid_t vendor_tbl_guid;
+		int ret;
+
+		ret = get_vendor_table((void *)cfg_tbl_pa, i,
+				       &vendor_tbl_pa,
+				       &vendor_tbl_guid, et);
+		if (ret)
+			return 0;
+
+		if (!efi_guidcmp(guid, vendor_tbl_guid))
+			return vendor_tbl_pa;
+	}
+
+	return 0;
+}
diff --git a/arch/x86/boot/compressed/efi.h b/arch/x86/boot/compressed/efi.h
new file mode 100644
index 000000000000..7db2f41b54cd
--- /dev/null
+++ b/arch/x86/boot/compressed/efi.h
@@ -0,0 +1,126 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef BOOT_COMPRESSED_EFI_H
+#define BOOT_COMPRESSED_EFI_H
+
+#if defined(_LINUX_EFI_H) || defined(_ASM_X86_EFI_H)
+#error Please do not include kernel proper namespace headers
+#endif
+
+typedef guid_t efi_guid_t __aligned(__alignof__(u32));
+
+#define EFI_GUID(a, b, c, d...) (efi_guid_t){ {					\
+	(a) & 0xff, ((a) >> 8) & 0xff, ((a) >> 16) & 0xff, ((a) >> 24) & 0xff,	\
+	(b) & 0xff, ((b) >> 8) & 0xff,						\
+	(c) & 0xff, ((c) >> 8) & 0xff, d } }
+
+#define ACPI_TABLE_GUID				EFI_GUID(0xeb9d2d30, 0x2d88, 0x11d3,  0x9a, 0x16, 0x00, 0x90, 0x27, 0x3f, 0xc1, 0x4d)
+#define ACPI_20_TABLE_GUID			EFI_GUID(0x8868e871, 0xe4f1, 0x11d3,  0xbc, 0x22, 0x00, 0x80, 0xc7, 0x3c, 0x88, 0x81)
+#define EFI_CC_BLOB_GUID			EFI_GUID(0x067b1f5f, 0xcf26, 0x44c5, 0x85, 0x54, 0x93, 0xd7, 0x77, 0x91, 0x2d, 0x42)
+
+#define EFI32_LOADER_SIGNATURE	"EL32"
+#define EFI64_LOADER_SIGNATURE	"EL64"
+
+/*
+ * Generic EFI table header
+ */
+typedef	struct {
+	u64 signature;
+	u32 revision;
+	u32 headersize;
+	u32 crc32;
+	u32 reserved;
+} efi_table_hdr_t;
+
+#define EFI_CONVENTIONAL_MEMORY		 7
+
+#define EFI_MEMORY_MORE_RELIABLE \
+				((u64)0x0000000000010000ULL)	/* higher reliability */
+#define EFI_MEMORY_SP		((u64)0x0000000000040000ULL)	/* soft reserved */
+
+#define EFI_PAGE_SHIFT		12
+
+typedef struct {
+	u32 type;
+	u32 pad;
+	u64 phys_addr;
+	u64 virt_addr;
+	u64 num_pages;
+	u64 attribute;
+} efi_memory_desc_t;
+
+#define efi_early_memdesc_ptr(map, desc_size, n)			\
+	(efi_memory_desc_t *)((void *)(map) + ((n) * (desc_size)))
+
+typedef struct {
+	efi_guid_t guid;
+	u64 table;
+} efi_config_table_64_t;
+
+typedef struct {
+	efi_guid_t guid;
+	u32 table;
+} efi_config_table_32_t;
+
+typedef struct {
+	efi_table_hdr_t hdr;
+	u64 fw_vendor;	/* physical addr of CHAR16 vendor string */
+	u32 fw_revision;
+	u32 __pad1;
+	u64 con_in_handle;
+	u64 con_in;
+	u64 con_out_handle;
+	u64 con_out;
+	u64 stderr_handle;
+	u64 stderr;
+	u64 runtime;
+	u64 boottime;
+	u32 nr_tables;
+	u32 __pad2;
+	u64 tables;
+} efi_system_table_64_t;
+
+typedef struct {
+	efi_table_hdr_t hdr;
+	u32 fw_vendor;	/* physical addr of CHAR16 vendor string */
+	u32 fw_revision;
+	u32 con_in_handle;
+	u32 con_in;
+	u32 con_out_handle;
+	u32 con_out;
+	u32 stderr_handle;
+	u32 stderr;
+	u32 runtime;
+	u32 boottime;
+	u32 nr_tables;
+	u32 tables;
+} efi_system_table_32_t;
+
+/* kexec external ABI */
+struct efi_setup_data {
+	u64 fw_vendor;
+	u64 __unused;
+	u64 tables;
+	u64 smbios;
+	u64 reserved[8];
+};
+
+static inline int efi_guidcmp (efi_guid_t left, efi_guid_t right)
+{
+	return memcmp(&left, &right, sizeof (efi_guid_t));
+}
+
+#ifdef CONFIG_EFI
+bool __pure __efi_soft_reserve_enabled(void);
+
+static inline bool __pure efi_soft_reserve_enabled(void)
+{
+	return IS_ENABLED(CONFIG_EFI_SOFT_RESERVE)
+		&& __efi_soft_reserve_enabled();
+}
+#else
+static inline bool efi_soft_reserve_enabled(void)
+{
+	return false;
+}
+#endif /* CONFIG_EFI */
+#endif /* BOOT_COMPRESSED_EFI_H */
diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S
index dea95301196b..d33f060900d2 100644
--- a/arch/x86/boot/compressed/head_64.S
+++ b/arch/x86/boot/compressed/head_64.S
@@ -189,11 +189,11 @@ SYM_FUNC_START(startup_32)
 	subl	$32, %eax	/* Encryption bit is always above bit 31 */
 	bts	%eax, %edx	/* Set encryption mask for page tables */
 	/*
-	 * Mark SEV as active in sev_status so that startup32_check_sev_cbit()
-	 * will do a check. The sev_status memory will be fully initialized
-	 * with the contents of MSR_AMD_SEV_STATUS later in
-	 * set_sev_encryption_mask(). For now it is sufficient to know that SEV
-	 * is active.
+	 * Set MSR_AMD64_SEV_ENABLED_BIT in sev_status so that
+	 * startup32_check_sev_cbit() will do a check. sev_enable() will
+	 * initialize sev_status with all the bits reported by
+	 * MSR_AMD_SEV_STATUS later, but only MSR_AMD64_SEV_ENABLED_BIT
+	 * needs to be set for now.
 	 */
 	movl	$1, rva(sev_status)(%ebp)
 1:
@@ -289,7 +289,7 @@ SYM_FUNC_START(startup_32)
 	pushl	%eax
 
 	/* Enter paged protected Mode, activating Long Mode */
-	movl	$(X86_CR0_PG | X86_CR0_PE), %eax /* Enable Paging and Protected mode */
+	movl	$CR0_STATE, %eax
 	movl	%eax, %cr0
 
 	/* Jump from 32bit compatibility mode into 64bit mode. */
@@ -447,6 +447,23 @@ SYM_CODE_START(startup_64)
 	call	load_stage1_idt
 	popq	%rsi
 
+#ifdef CONFIG_AMD_MEM_ENCRYPT
+	/*
+	 * Now that the stage1 interrupt handlers are set up, #VC exceptions from
+	 * CPUID instructions can be properly handled for SEV-ES guests.
+	 *
+	 * For SEV-SNP, the CPUID table also needs to be set up in advance of any
+	 * CPUID instructions being issued, so go ahead and do that now via
+	 * sev_enable(), which will also handle the rest of the SEV-related
+	 * detection/setup to ensure that has been done in advance of any dependent
+	 * code.
+	 */
+	pushq	%rsi
+	movq	%rsi, %rdi		/* real mode address */
+	call	sev_enable
+	popq	%rsi
+#endif
+
 	/*
 	 * paging_prepare() sets up the trampoline and checks if we need to
 	 * enable 5-level paging.
@@ -558,17 +575,7 @@ SYM_FUNC_START_LOCAL_NOALIGN(.Lrelocated)
 	shrq	$3, %rcx
 	rep	stosq
 
-/*
- * If running as an SEV guest, the encryption mask is required in the
- * page-table setup code below. When the guest also has SEV-ES enabled
- * set_sev_encryption_mask() will cause #VC exceptions, but the stage2
- * handler can't map its GHCB because the page-table is not set up yet.
- * So set up the encryption mask here while still on the stage1 #VC
- * handler. Then load stage2 IDT and switch to the kernel's own
- * page-table.
- */
 	pushq	%rsi
-	call	set_sev_encryption_mask
 	call	load_stage2_idt
 
 	/* Pass boot_params to initialize_identity_maps() */
@@ -642,12 +649,28 @@ SYM_CODE_START(trampoline_32bit_src)
 	movl	$MSR_EFER, %ecx
 	rdmsr
 	btsl	$_EFER_LME, %eax
+	/* Avoid writing EFER if no change was made (for TDX guest) */
+	jc	1f
 	wrmsr
-	popl	%edx
+1:	popl	%edx
 	popl	%ecx
 
+#ifdef CONFIG_X86_MCE
+	/*
+	 * Preserve CR4.MCE if the kernel will enable #MC support.
+	 * Clearing MCE may fault in some environments (that also force #MC
+	 * support). Any machine check that occurs before #MC support is fully
+	 * configured will crash the system regardless of the CR4.MCE value set
+	 * here.
+	 */
+	movl	%cr4, %eax
+	andl	$X86_CR4_MCE, %eax
+#else
+	movl	$0, %eax
+#endif
+
 	/* Enable PAE and LA57 (if required) paging modes */
-	movl	$X86_CR4_PAE, %eax
+	orl	$X86_CR4_PAE, %eax
 	testl	%edx, %edx
 	jz	1f
 	orl	$X86_CR4_LA57, %eax
@@ -661,8 +684,9 @@ SYM_CODE_START(trampoline_32bit_src)
 	pushl	$__KERNEL_CS
 	pushl	%eax
 
-	/* Enable paging again */
-	movl	$(X86_CR0_PG | X86_CR0_PE), %eax
+	/* Enable paging again. */
+	movl	%cr0, %eax
+	btsl	$X86_CR0_PG_BIT, %eax
 	movl	%eax, %cr0
 
 	lret
diff --git a/arch/x86/boot/compressed/ident_map_64.c b/arch/x86/boot/compressed/ident_map_64.c
index f7213d0943b8..44c350d627c7 100644
--- a/arch/x86/boot/compressed/ident_map_64.c
+++ b/arch/x86/boot/compressed/ident_map_64.c
@@ -90,7 +90,7 @@ static struct x86_mapping_info mapping_info;
 /*
  * Adds the specified range to the identity mappings.
  */
-static void add_identity_map(unsigned long start, unsigned long end)
+void kernel_add_identity_map(unsigned long start, unsigned long end)
 {
 	int ret;
 
@@ -157,14 +157,15 @@ void initialize_identity_maps(void *rmode)
 	 * explicitly here in case the compressed kernel does not touch them,
 	 * or does not touch all the pages covering them.
 	 */
-	add_identity_map((unsigned long)_head, (unsigned long)_end);
+	kernel_add_identity_map((unsigned long)_head, (unsigned long)_end);
 	boot_params = rmode;
-	add_identity_map((unsigned long)boot_params, (unsigned long)(boot_params + 1));
+	kernel_add_identity_map((unsigned long)boot_params, (unsigned long)(boot_params + 1));
 	cmdline = get_cmd_line_ptr();
-	add_identity_map(cmdline, cmdline + COMMAND_LINE_SIZE);
+	kernel_add_identity_map(cmdline, cmdline + COMMAND_LINE_SIZE);
+
+	sev_prep_identity_maps(top_level_pgt);
 
 	/* Load the new page-table. */
-	sev_verify_cbit(top_level_pgt);
 	write_cr3(top_level_pgt);
 }
 
@@ -246,10 +247,10 @@ static int set_clr_page_flags(struct x86_mapping_info *info,
 	 * It should already exist, but keep things generic.
 	 *
 	 * To map the page just read from it and fault it in if there is no
-	 * mapping yet. add_identity_map() can't be called here because that
-	 * would unconditionally map the address on PMD level, destroying any
-	 * PTE-level mappings that might already exist. Use assembly here so
-	 * the access won't be optimized away.
+	 * mapping yet. kernel_add_identity_map() can't be called here because
+	 * that would unconditionally map the address on PMD level, destroying
+	 * any PTE-level mappings that might already exist. Use assembly here
+	 * so the access won't be optimized away.
 	 */
 	asm volatile("mov %[address], %%r9"
 		     :: [address] "g" (*(unsigned long *)address)
@@ -275,15 +276,31 @@ static int set_clr_page_flags(struct x86_mapping_info *info,
 	 * Changing encryption attributes of a page requires to flush it from
 	 * the caches.
 	 */
-	if ((set | clr) & _PAGE_ENC)
+	if ((set | clr) & _PAGE_ENC) {
 		clflush_page(address);
 
+		/*
+		 * If the encryption attribute is being cleared, change the page state
+		 * to shared in the RMP table.
+		 */
+		if (clr)
+			snp_set_page_shared(__pa(address & PAGE_MASK));
+	}
+
 	/* Update PTE */
 	pte = *ptep;
 	pte = pte_set_flags(pte, set);
 	pte = pte_clear_flags(pte, clr);
 	set_pte(ptep, pte);
 
+	/*
+	 * If the encryption attribute is being set, then change the page state to
+	 * private in the RMP entry. The page state change must be done after the PTE
+	 * is updated.
+	 */
+	if (set & _PAGE_ENC)
+		snp_set_page_private(__pa(address & PAGE_MASK));
+
 	/* Flush TLB after changing encryption attribute */
 	write_cr3(top_level_pgt);
 
@@ -347,5 +364,5 @@ void do_boot_page_fault(struct pt_regs *regs, unsigned long error_code)
 	 * Error code is sane - now identity map the 2M region around
 	 * the faulting address.
 	 */
-	add_identity_map(address, end);
+	kernel_add_identity_map(address, end);
 }
diff --git a/arch/x86/boot/compressed/idt_64.c b/arch/x86/boot/compressed/idt_64.c
index 9b93567d663a..6debb816e83d 100644
--- a/arch/x86/boot/compressed/idt_64.c
+++ b/arch/x86/boot/compressed/idt_64.c
@@ -39,7 +39,23 @@ void load_stage1_idt(void)
 	load_boot_idt(&boot_idt_desc);
 }
 
-/* Setup IDT after kernel jumping to  .Lrelocated */
+/*
+ * Setup IDT after kernel jumping to  .Lrelocated.
+ *
+ * initialize_identity_maps() needs a #PF handler to be setup
+ * in order to be able to fault-in identity mapping ranges; see
+ * do_boot_page_fault().
+ *
+ * This #PF handler setup needs to happen in load_stage2_idt() where the
+ * IDT is loaded and there the #VC IDT entry gets setup too.
+ *
+ * In order to be able to handle #VCs, one needs a GHCB which
+ * gets setup with an already set up pagetable, which is done in
+ * initialize_identity_maps(). And there's the catch 22: the boot #VC
+ * handler do_boot_stage2_vc() needs to call early_setup_ghcb() itself
+ * (and, especially set_page_decrypted()) because the SEV-ES setup code
+ * cannot initialize a GHCB as there's no #PF handler yet...
+ */
 void load_stage2_idt(void)
 {
 	boot_idt_desc.address = (unsigned long)boot_idt;
diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c
index 411b268bc0a2..4a3f223973f4 100644
--- a/arch/x86/boot/compressed/kaslr.c
+++ b/arch/x86/boot/compressed/kaslr.c
@@ -22,15 +22,14 @@
 #include "misc.h"
 #include "error.h"
 #include "../string.h"
+#include "efi.h"
 
 #include <generated/compile.h>
 #include <linux/module.h>
 #include <linux/uts.h>
 #include <linux/utsname.h>
 #include <linux/ctype.h>
-#include <linux/efi.h>
 #include <generated/utsrelease.h>
-#include <asm/efi.h>
 
 #define _SETUP
 #include <asm/setup.h>	/* For COMMAND_LINE_SIZE */
diff --git a/arch/x86/boot/compressed/mem_encrypt.S b/arch/x86/boot/compressed/mem_encrypt.S
index a63424d13627..a73e4d783cae 100644
--- a/arch/x86/boot/compressed/mem_encrypt.S
+++ b/arch/x86/boot/compressed/mem_encrypt.S
@@ -187,42 +187,6 @@ SYM_CODE_END(startup32_vc_handler)
 	.code64
 
 #include "../../kernel/sev_verify_cbit.S"
-SYM_FUNC_START(set_sev_encryption_mask)
-#ifdef CONFIG_AMD_MEM_ENCRYPT
-	push	%rbp
-	push	%rdx
-
-	movq	%rsp, %rbp		/* Save current stack pointer */
-
-	call	get_sev_encryption_bit	/* Get the encryption bit position */
-	testl	%eax, %eax
-	jz	.Lno_sev_mask
-
-	bts	%rax, sme_me_mask(%rip)	/* Create the encryption mask */
-
-	/*
-	 * Read MSR_AMD64_SEV again and store it to sev_status. Can't do this in
-	 * get_sev_encryption_bit() because this function is 32-bit code and
-	 * shared between 64-bit and 32-bit boot path.
-	 */
-	movl	$MSR_AMD64_SEV, %ecx	/* Read the SEV MSR */
-	rdmsr
-
-	/* Store MSR value in sev_status */
-	shlq	$32, %rdx
-	orq	%rdx, %rax
-	movq	%rax, sev_status(%rip)
-
-.Lno_sev_mask:
-	movq	%rbp, %rsp		/* Restore original stack pointer */
-
-	pop	%rdx
-	pop	%rbp
-#endif
-
-	xor	%rax, %rax
-	RET
-SYM_FUNC_END(set_sev_encryption_mask)
 
 	.data
 
diff --git a/arch/x86/boot/compressed/misc.c b/arch/x86/boot/compressed/misc.c
index 1cdcaf34ee36..cf690d8712f4 100644
--- a/arch/x86/boot/compressed/misc.c
+++ b/arch/x86/boot/compressed/misc.c
@@ -48,12 +48,17 @@ void *memmove(void *dest, const void *src, size_t n);
  */
 struct boot_params *boot_params;
 
+struct port_io_ops pio_ops;
+
 memptr free_mem_ptr;
 memptr free_mem_end_ptr;
 
 static char *vidmem;
 static int vidport;
-static int lines, cols;
+
+/* These might be accessed before .bss is cleared, so use .data instead. */
+static int lines __section(".data");
+static int cols __section(".data");
 
 #ifdef CONFIG_KERNEL_GZIP
 #include "../../../../lib/decompress_inflate.c"
@@ -371,6 +376,16 @@ asmlinkage __visible void *extract_kernel(void *rmode, memptr heap,
 	lines = boot_params->screen_info.orig_video_lines;
 	cols = boot_params->screen_info.orig_video_cols;
 
+	init_default_io_ops();
+
+	/*
+	 * Detect TDX guest environment.
+	 *
+	 * It has to be done before console_init() in order to use
+	 * paravirtualized port I/O operations if needed.
+	 */
+	early_tdx_detect();
+
 	console_init();
 
 	/*
diff --git a/arch/x86/boot/compressed/misc.h b/arch/x86/boot/compressed/misc.h
index 16ed360b6692..4910bf230d7b 100644
--- a/arch/x86/boot/compressed/misc.h
+++ b/arch/x86/boot/compressed/misc.h
@@ -22,17 +22,21 @@
 #include <linux/linkage.h>
 #include <linux/screen_info.h>
 #include <linux/elf.h>
-#include <linux/io.h>
 #include <asm/page.h>
 #include <asm/boot.h>
 #include <asm/bootparam.h>
 #include <asm/desc_defs.h>
 
+#include "tdx.h"
+
 #define BOOT_CTYPE_H
 #include <linux/acpi.h>
 
 #define BOOT_BOOT_H
 #include "../ctype.h"
+#include "../io.h"
+
+#include "efi.h"
 
 #ifdef CONFIG_X86_64
 #define memptr long
@@ -120,17 +124,23 @@ static inline void console_init(void)
 { }
 #endif
 
-void set_sev_encryption_mask(void);
-
 #ifdef CONFIG_AMD_MEM_ENCRYPT
+void sev_enable(struct boot_params *bp);
 void sev_es_shutdown_ghcb(void);
 extern bool sev_es_check_ghcb_fault(unsigned long address);
+void snp_set_page_private(unsigned long paddr);
+void snp_set_page_shared(unsigned long paddr);
+void sev_prep_identity_maps(unsigned long top_level_pgt);
 #else
+static inline void sev_enable(struct boot_params *bp) { }
 static inline void sev_es_shutdown_ghcb(void) { }
 static inline bool sev_es_check_ghcb_fault(unsigned long address)
 {
 	return false;
 }
+static inline void snp_set_page_private(unsigned long paddr) { }
+static inline void snp_set_page_shared(unsigned long paddr) { }
+static inline void sev_prep_identity_maps(unsigned long top_level_pgt) { }
 #endif
 
 /* acpi.c */
@@ -151,6 +161,7 @@ static inline int count_immovable_mem_regions(void) { return 0; }
 #ifdef CONFIG_X86_5LEVEL
 extern unsigned int __pgtable_l5_enabled, pgdir_shift, ptrs_per_p4d;
 #endif
+extern void kernel_add_identity_map(unsigned long start, unsigned long end);
 
 /* Used by PAGE_KERN* macros: */
 extern pteval_t __default_kernel_pte_mask;
@@ -172,4 +183,47 @@ void boot_stage2_vc(void);
 
 unsigned long sev_verify_cbit(unsigned long cr3);
 
+enum efi_type {
+	EFI_TYPE_64,
+	EFI_TYPE_32,
+	EFI_TYPE_NONE,
+};
+
+#ifdef CONFIG_EFI
+/* helpers for early EFI config table access */
+enum efi_type efi_get_type(struct boot_params *bp);
+unsigned long efi_get_system_table(struct boot_params *bp);
+int efi_get_conf_table(struct boot_params *bp, unsigned long *cfg_tbl_pa,
+		       unsigned int *cfg_tbl_len);
+unsigned long efi_find_vendor_table(struct boot_params *bp,
+				    unsigned long cfg_tbl_pa,
+				    unsigned int cfg_tbl_len,
+				    efi_guid_t guid);
+#else
+static inline enum efi_type efi_get_type(struct boot_params *bp)
+{
+	return EFI_TYPE_NONE;
+}
+
+static inline unsigned long efi_get_system_table(struct boot_params *bp)
+{
+	return 0;
+}
+
+static inline int efi_get_conf_table(struct boot_params *bp,
+				     unsigned long *cfg_tbl_pa,
+				     unsigned int *cfg_tbl_len)
+{
+	return -ENOENT;
+}
+
+static inline unsigned long efi_find_vendor_table(struct boot_params *bp,
+						  unsigned long cfg_tbl_pa,
+						  unsigned int cfg_tbl_len,
+						  efi_guid_t guid)
+{
+	return 0;
+}
+#endif /* CONFIG_EFI */
+
 #endif /* BOOT_COMPRESSED_MISC_H */
diff --git a/arch/x86/boot/compressed/pgtable.h b/arch/x86/boot/compressed/pgtable.h
index 6ff7e81b5628..cc9b2529a086 100644
--- a/arch/x86/boot/compressed/pgtable.h
+++ b/arch/x86/boot/compressed/pgtable.h
@@ -6,7 +6,7 @@
 #define TRAMPOLINE_32BIT_PGTABLE_OFFSET	0
 
 #define TRAMPOLINE_32BIT_CODE_OFFSET	PAGE_SIZE
-#define TRAMPOLINE_32BIT_CODE_SIZE	0x70
+#define TRAMPOLINE_32BIT_CODE_SIZE	0x80
 
 #define TRAMPOLINE_32BIT_STACK_END	TRAMPOLINE_32BIT_SIZE
 
diff --git a/arch/x86/boot/compressed/pgtable_64.c b/arch/x86/boot/compressed/pgtable_64.c
index a1733319a22a..2ac12ff4111b 100644
--- a/arch/x86/boot/compressed/pgtable_64.c
+++ b/arch/x86/boot/compressed/pgtable_64.c
@@ -1,11 +1,10 @@
 // SPDX-License-Identifier: GPL-2.0
 #include "misc.h"
-#include <linux/efi.h>
 #include <asm/e820/types.h>
 #include <asm/processor.h>
-#include <asm/efi.h>
 #include "pgtable.h"
 #include "../string.h"
+#include "efi.h"
 
 #define BIOS_START_MIN		0x20000U	/* 128K, less than this is insane */
 #define BIOS_START_MAX		0x9f000U	/* 640K, absolute maximum */
diff --git a/arch/x86/boot/compressed/sev.c b/arch/x86/boot/compressed/sev.c
index 28bcf04c022e..52f989f6acc2 100644
--- a/arch/x86/boot/compressed/sev.c
+++ b/arch/x86/boot/compressed/sev.c
@@ -20,8 +20,10 @@
 #include <asm/fpu/xcr.h>
 #include <asm/ptrace.h>
 #include <asm/svm.h>
+#include <asm/cpuid.h>
 
 #include "error.h"
+#include "../msr.h"
 
 struct ghcb boot_ghcb_page __aligned(PAGE_SIZE);
 struct ghcb *boot_ghcb;
@@ -56,23 +58,19 @@ static unsigned long insn_get_seg_base(struct pt_regs *regs, int seg_reg_idx)
 
 static inline u64 sev_es_rd_ghcb_msr(void)
 {
-	unsigned long low, high;
+	struct msr m;
 
-	asm volatile("rdmsr" : "=a" (low), "=d" (high) :
-			"c" (MSR_AMD64_SEV_ES_GHCB));
+	boot_rdmsr(MSR_AMD64_SEV_ES_GHCB, &m);
 
-	return ((high << 32) | low);
+	return m.q;
 }
 
 static inline void sev_es_wr_ghcb_msr(u64 val)
 {
-	u32 low, high;
+	struct msr m;
 
-	low  = val & 0xffffffffUL;
-	high = val >> 32;
-
-	asm volatile("wrmsr" : : "c" (MSR_AMD64_SEV_ES_GHCB),
-			"a"(low), "d" (high) : "memory");
+	m.q = val;
+	boot_wrmsr(MSR_AMD64_SEV_ES_GHCB, &m);
 }
 
 static enum es_result vc_decode_insn(struct es_em_ctxt *ctxt)
@@ -119,11 +117,54 @@ static enum es_result vc_read_mem(struct es_em_ctxt *ctxt,
 /* Include code for early handlers */
 #include "../../kernel/sev-shared.c"
 
-static bool early_setup_sev_es(void)
+static inline bool sev_snp_enabled(void)
+{
+	return sev_status & MSR_AMD64_SEV_SNP_ENABLED;
+}
+
+static void __page_state_change(unsigned long paddr, enum psc_op op)
+{
+	u64 val;
+
+	if (!sev_snp_enabled())
+		return;
+
+	/*
+	 * If private -> shared then invalidate the page before requesting the
+	 * state change in the RMP table.
+	 */
+	if (op == SNP_PAGE_STATE_SHARED && pvalidate(paddr, RMP_PG_SIZE_4K, 0))
+		sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_PVALIDATE);
+
+	/* Issue VMGEXIT to change the page state in RMP table. */
+	sev_es_wr_ghcb_msr(GHCB_MSR_PSC_REQ_GFN(paddr >> PAGE_SHIFT, op));
+	VMGEXIT();
+
+	/* Read the response of the VMGEXIT. */
+	val = sev_es_rd_ghcb_msr();
+	if ((GHCB_RESP_CODE(val) != GHCB_MSR_PSC_RESP) || GHCB_MSR_PSC_RESP_VAL(val))
+		sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_PSC);
+
+	/*
+	 * Now that page state is changed in the RMP table, validate it so that it is
+	 * consistent with the RMP entry.
+	 */
+	if (op == SNP_PAGE_STATE_PRIVATE && pvalidate(paddr, RMP_PG_SIZE_4K, 1))
+		sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_PVALIDATE);
+}
+
+void snp_set_page_private(unsigned long paddr)
+{
+	__page_state_change(paddr, SNP_PAGE_STATE_PRIVATE);
+}
+
+void snp_set_page_shared(unsigned long paddr)
 {
-	if (!sev_es_negotiate_protocol())
-		sev_es_terminate(GHCB_SEV_ES_PROT_UNSUPPORTED);
+	__page_state_change(paddr, SNP_PAGE_STATE_SHARED);
+}
 
+static bool early_setup_ghcb(void)
+{
 	if (set_page_decrypted((unsigned long)&boot_ghcb_page))
 		return false;
 
@@ -135,6 +176,10 @@ static bool early_setup_sev_es(void)
 	/* Initialize lookup tables for the instruction decoder */
 	inat_init_tables();
 
+	/* SNP guest requires the GHCB GPA must be registered */
+	if (sev_snp_enabled())
+		snp_register_ghcb_early(__pa(&boot_ghcb_page));
+
 	return true;
 }
 
@@ -174,8 +219,8 @@ void do_boot_stage2_vc(struct pt_regs *regs, unsigned long exit_code)
 	struct es_em_ctxt ctxt;
 	enum es_result result;
 
-	if (!boot_ghcb && !early_setup_sev_es())
-		sev_es_terminate(GHCB_SEV_ES_GEN_REQ);
+	if (!boot_ghcb && !early_setup_ghcb())
+		sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SEV_ES_GEN_REQ);
 
 	vc_ghcb_invalidate(boot_ghcb);
 	result = vc_init_em_ctxt(&ctxt, regs, exit_code);
@@ -202,5 +247,191 @@ finish:
 	if (result == ES_OK)
 		vc_finish_insn(&ctxt);
 	else if (result != ES_RETRY)
-		sev_es_terminate(GHCB_SEV_ES_GEN_REQ);
+		sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SEV_ES_GEN_REQ);
+}
+
+static void enforce_vmpl0(void)
+{
+	u64 attrs;
+	int err;
+
+	/*
+	 * RMPADJUST modifies RMP permissions of a lesser-privileged (numerically
+	 * higher) privilege level. Here, clear the VMPL1 permission mask of the
+	 * GHCB page. If the guest is not running at VMPL0, this will fail.
+	 *
+	 * If the guest is running at VMPL0, it will succeed. Even if that operation
+	 * modifies permission bits, it is still ok to do so currently because Linux
+	 * SNP guests are supported only on VMPL0 so VMPL1 or higher permission masks
+	 * changing is a don't-care.
+	 */
+	attrs = 1;
+	if (rmpadjust((unsigned long)&boot_ghcb_page, RMP_PG_SIZE_4K, attrs))
+		sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_NOT_VMPL0);
+}
+
+void sev_enable(struct boot_params *bp)
+{
+	unsigned int eax, ebx, ecx, edx;
+	struct msr m;
+	bool snp;
+
+	/*
+	 * Setup/preliminary detection of SNP. This will be sanity-checked
+	 * against CPUID/MSR values later.
+	 */
+	snp = snp_init(bp);
+
+	/* Check for the SME/SEV support leaf */
+	eax = 0x80000000;
+	ecx = 0;
+	native_cpuid(&eax, &ebx, &ecx, &edx);
+	if (eax < 0x8000001f)
+		return;
+
+	/*
+	 * Check for the SME/SEV feature:
+	 *   CPUID Fn8000_001F[EAX]
+	 *   - Bit 0 - Secure Memory Encryption support
+	 *   - Bit 1 - Secure Encrypted Virtualization support
+	 *   CPUID Fn8000_001F[EBX]
+	 *   - Bits 5:0 - Pagetable bit position used to indicate encryption
+	 */
+	eax = 0x8000001f;
+	ecx = 0;
+	native_cpuid(&eax, &ebx, &ecx, &edx);
+	/* Check whether SEV is supported */
+	if (!(eax & BIT(1))) {
+		if (snp)
+			error("SEV-SNP support indicated by CC blob, but not CPUID.");
+		return;
+	}
+
+	/* Set the SME mask if this is an SEV guest. */
+	boot_rdmsr(MSR_AMD64_SEV, &m);
+	sev_status = m.q;
+	if (!(sev_status & MSR_AMD64_SEV_ENABLED))
+		return;
+
+	/* Negotiate the GHCB protocol version. */
+	if (sev_status & MSR_AMD64_SEV_ES_ENABLED) {
+		if (!sev_es_negotiate_protocol())
+			sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SEV_ES_PROT_UNSUPPORTED);
+	}
+
+	/*
+	 * SNP is supported in v2 of the GHCB spec which mandates support for HV
+	 * features.
+	 */
+	if (sev_status & MSR_AMD64_SEV_SNP_ENABLED) {
+		if (!(get_hv_features() & GHCB_HV_FT_SNP))
+			sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SNP_UNSUPPORTED);
+
+		enforce_vmpl0();
+	}
+
+	if (snp && !(sev_status & MSR_AMD64_SEV_SNP_ENABLED))
+		error("SEV-SNP supported indicated by CC blob, but not SEV status MSR.");
+
+	sme_me_mask = BIT_ULL(ebx & 0x3f);
+}
+
+/* Search for Confidential Computing blob in the EFI config table. */
+static struct cc_blob_sev_info *find_cc_blob_efi(struct boot_params *bp)
+{
+	unsigned long cfg_table_pa;
+	unsigned int cfg_table_len;
+	int ret;
+
+	ret = efi_get_conf_table(bp, &cfg_table_pa, &cfg_table_len);
+	if (ret)
+		return NULL;
+
+	return (struct cc_blob_sev_info *)efi_find_vendor_table(bp, cfg_table_pa,
+								cfg_table_len,
+								EFI_CC_BLOB_GUID);
+}
+
+/*
+ * Initial set up of SNP relies on information provided by the
+ * Confidential Computing blob, which can be passed to the boot kernel
+ * by firmware/bootloader in the following ways:
+ *
+ * - via an entry in the EFI config table
+ * - via a setup_data structure, as defined by the Linux Boot Protocol
+ *
+ * Scan for the blob in that order.
+ */
+static struct cc_blob_sev_info *find_cc_blob(struct boot_params *bp)
+{
+	struct cc_blob_sev_info *cc_info;
+
+	cc_info = find_cc_blob_efi(bp);
+	if (cc_info)
+		goto found_cc_info;
+
+	cc_info = find_cc_blob_setup_data(bp);
+	if (!cc_info)
+		return NULL;
+
+found_cc_info:
+	if (cc_info->magic != CC_BLOB_SEV_HDR_MAGIC)
+		sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SNP_UNSUPPORTED);
+
+	return cc_info;
+}
+
+/*
+ * Indicate SNP based on presence of SNP-specific CC blob. Subsequent checks
+ * will verify the SNP CPUID/MSR bits.
+ */
+bool snp_init(struct boot_params *bp)
+{
+	struct cc_blob_sev_info *cc_info;
+
+	if (!bp)
+		return false;
+
+	cc_info = find_cc_blob(bp);
+	if (!cc_info)
+		return false;
+
+	/*
+	 * If a SNP-specific Confidential Computing blob is present, then
+	 * firmware/bootloader have indicated SNP support. Verifying this
+	 * involves CPUID checks which will be more reliable if the SNP
+	 * CPUID table is used. See comments over snp_setup_cpuid_table() for
+	 * more details.
+	 */
+	setup_cpuid_table(cc_info);
+
+	/*
+	 * Pass run-time kernel a pointer to CC info via boot_params so EFI
+	 * config table doesn't need to be searched again during early startup
+	 * phase.
+	 */
+	bp->cc_blob_address = (u32)(unsigned long)cc_info;
+
+	return true;
+}
+
+void sev_prep_identity_maps(unsigned long top_level_pgt)
+{
+	/*
+	 * The Confidential Computing blob is used very early in uncompressed
+	 * kernel to find the in-memory CPUID table to handle CPUID
+	 * instructions. Make sure an identity-mapping exists so it can be
+	 * accessed after switchover.
+	 */
+	if (sev_snp_enabled()) {
+		unsigned long cc_info_pa = boot_params->cc_blob_address;
+		struct cc_blob_sev_info *cc_info;
+
+		kernel_add_identity_map(cc_info_pa, cc_info_pa + sizeof(*cc_info));
+
+		cc_info = (struct cc_blob_sev_info *)cc_info_pa;
+		kernel_add_identity_map(cc_info->cpuid_phys, cc_info->cpuid_phys + cc_info->cpuid_len);
+	}
+
+	sev_verify_cbit(top_level_pgt);
 }
diff --git a/arch/x86/boot/compressed/tdcall.S b/arch/x86/boot/compressed/tdcall.S
new file mode 100644
index 000000000000..46d0495e0d3a
--- /dev/null
+++ b/arch/x86/boot/compressed/tdcall.S
@@ -0,0 +1,3 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#include "../../coco/tdx/tdcall.S"
diff --git a/arch/x86/boot/compressed/tdx.c b/arch/x86/boot/compressed/tdx.c
new file mode 100644
index 000000000000..918a7606f53c
--- /dev/null
+++ b/arch/x86/boot/compressed/tdx.c
@@ -0,0 +1,77 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include "../cpuflags.h"
+#include "../string.h"
+#include "../io.h"
+#include "error.h"
+
+#include <vdso/limits.h>
+#include <uapi/asm/vmx.h>
+
+#include <asm/shared/tdx.h>
+
+/* Called from __tdx_hypercall() for unrecoverable failure */
+void __tdx_hypercall_failed(void)
+{
+	error("TDVMCALL failed. TDX module bug?");
+}
+
+static inline unsigned int tdx_io_in(int size, u16 port)
+{
+	struct tdx_hypercall_args args = {
+		.r10 = TDX_HYPERCALL_STANDARD,
+		.r11 = EXIT_REASON_IO_INSTRUCTION,
+		.r12 = size,
+		.r13 = 0,
+		.r14 = port,
+	};
+
+	if (__tdx_hypercall(&args, TDX_HCALL_HAS_OUTPUT))
+		return UINT_MAX;
+
+	return args.r11;
+}
+
+static inline void tdx_io_out(int size, u16 port, u32 value)
+{
+	struct tdx_hypercall_args args = {
+		.r10 = TDX_HYPERCALL_STANDARD,
+		.r11 = EXIT_REASON_IO_INSTRUCTION,
+		.r12 = size,
+		.r13 = 1,
+		.r14 = port,
+		.r15 = value,
+	};
+
+	__tdx_hypercall(&args, 0);
+}
+
+static inline u8 tdx_inb(u16 port)
+{
+	return tdx_io_in(1, port);
+}
+
+static inline void tdx_outb(u8 value, u16 port)
+{
+	tdx_io_out(1, port, value);
+}
+
+static inline void tdx_outw(u16 value, u16 port)
+{
+	tdx_io_out(2, port, value);
+}
+
+void early_tdx_detect(void)
+{
+	u32 eax, sig[3];
+
+	cpuid_count(TDX_CPUID_LEAF_ID, 0, &eax, &sig[0], &sig[2],  &sig[1]);
+
+	if (memcmp(TDX_IDENT, sig, sizeof(sig)))
+		return;
+
+	/* Use hypercalls instead of I/O instructions */
+	pio_ops.f_inb  = tdx_inb;
+	pio_ops.f_outb = tdx_outb;
+	pio_ops.f_outw = tdx_outw;
+}
diff --git a/arch/x86/boot/compressed/tdx.h b/arch/x86/boot/compressed/tdx.h
new file mode 100644
index 000000000000..9055482cd35c
--- /dev/null
+++ b/arch/x86/boot/compressed/tdx.h
@@ -0,0 +1,13 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef BOOT_COMPRESSED_TDX_H
+#define BOOT_COMPRESSED_TDX_H
+
+#include <linux/types.h>
+
+#ifdef CONFIG_INTEL_TDX_GUEST
+void early_tdx_detect(void);
+#else
+static inline void early_tdx_detect(void) { };
+#endif
+
+#endif /* BOOT_COMPRESSED_TDX_H */