diff --git a/Documentation/x86/amd-memory-encryption.rst b/Documentation/x86/amd-memory-encryption.rst
index a1940ebe7be50cb17260b240a3ce78ec4f6a2242..934310ce7258298008e4c6ba5be611105993e1c1 100644
--- a/Documentation/x86/amd-memory-encryption.rst
+++ b/Documentation/x86/amd-memory-encryption.rst
@@ -95,3 +95,39 @@ by supplying mem_encrypt=on on the kernel command line.  However, if BIOS does
 not enable SME, then Linux will not be able to activate memory encryption, even
 if configured to do so by default or the mem_encrypt=on command line parameter
 is specified.
+
+Secure Nested Paging (SNP)
+==========================
+
+SEV-SNP introduces new features (SEV_FEATURES[1:63]) which can be enabled
+by the hypervisor for security enhancements. Some of these features need
+guest side implementation to function correctly. The below table lists the
+expected guest behavior with various possible scenarios of guest/hypervisor
+SNP feature support.
+
++-----------------+---------------+---------------+------------------+
+| Feature Enabled | Guest needs   | Guest has     | Guest boot       |
+| by the HV       | implementation| implementation| behaviour        |
++=================+===============+===============+==================+
+|      No         |      No       |      No       |     Boot         |
+|                 |               |               |                  |
++-----------------+---------------+---------------+------------------+
+|      No         |      Yes      |      No       |     Boot         |
+|                 |               |               |                  |
++-----------------+---------------+---------------+------------------+
+|      No         |      Yes      |      Yes      |     Boot         |
+|                 |               |               |                  |
++-----------------+---------------+---------------+------------------+
+|      Yes        |      No       |      No       | Boot with        |
+|                 |               |               | feature enabled  |
++-----------------+---------------+---------------+------------------+
+|      Yes        |      Yes      |      No       | Graceful boot    |
+|                 |               |               | failure          |
++-----------------+---------------+---------------+------------------+
+|      Yes        |      Yes      |      Yes      | Boot with        |
+|                 |               |               | feature enabled  |
++-----------------+---------------+---------------+------------------+
+
+More details in AMD64 APM[1] Vol 2: 15.34.10 SEV_STATUS MSR
+
+[1] https://www.amd.com/system/files/TechDocs/40332.pdf
diff --git a/arch/x86/Makefile b/arch/x86/Makefile
index 9cf07322875a42f914f16505a16003250f02cceb..73ed982d41000059e6d0f7e78c90e87d7f7d0390 100644
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -14,13 +14,13 @@ endif
 
 ifdef CONFIG_CC_IS_GCC
 RETPOLINE_CFLAGS	:= $(call cc-option,-mindirect-branch=thunk-extern -mindirect-branch-register)
-RETPOLINE_CFLAGS	+= $(call cc-option,-mindirect-branch-cs-prefix)
 RETPOLINE_VDSO_CFLAGS	:= $(call cc-option,-mindirect-branch=thunk-inline -mindirect-branch-register)
 endif
 ifdef CONFIG_CC_IS_CLANG
 RETPOLINE_CFLAGS	:= -mretpoline-external-thunk
 RETPOLINE_VDSO_CFLAGS	:= -mretpoline
 endif
+RETPOLINE_CFLAGS	+= $(call cc-option,-mindirect-branch-cs-prefix)
 
 ifdef CONFIG_RETHUNK
 RETHUNK_CFLAGS		:= -mfunction-return=thunk-extern
diff --git a/arch/x86/boot/compressed/ident_map_64.c b/arch/x86/boot/compressed/ident_map_64.c
index d4a314cc50d6ee6ecaa7268f59bbb946c71fb916..321a5011042d40f51120ff910786f6c17e80aaef 100644
--- a/arch/x86/boot/compressed/ident_map_64.c
+++ b/arch/x86/boot/compressed/ident_map_64.c
@@ -180,6 +180,12 @@ void initialize_identity_maps(void *rmode)
 
 	/* Load the new page-table. */
 	write_cr3(top_level_pgt);
+
+	/*
+	 * Now that the required page table mappings are established and a
+	 * GHCB can be used, check for SNP guest/HV feature compatibility.
+	 */
+	snp_check_features();
 }
 
 static pte_t *split_large_pmd(struct x86_mapping_info *info,
diff --git a/arch/x86/boot/compressed/misc.h b/arch/x86/boot/compressed/misc.h
index 62208ec04ca4b800e7cf3eb8949f6cf6a228fee2..20118fb7c53bbbec630a87cac129096a311ebef0 100644
--- a/arch/x86/boot/compressed/misc.h
+++ b/arch/x86/boot/compressed/misc.h
@@ -126,6 +126,7 @@ static inline void console_init(void)
 
 #ifdef CONFIG_AMD_MEM_ENCRYPT
 void sev_enable(struct boot_params *bp);
+void snp_check_features(void);
 void sev_es_shutdown_ghcb(void);
 extern bool sev_es_check_ghcb_fault(unsigned long address);
 void snp_set_page_private(unsigned long paddr);
@@ -143,6 +144,7 @@ static inline void sev_enable(struct boot_params *bp)
 	if (bp)
 		bp->cc_blob_address = 0;
 }
+static inline void snp_check_features(void) { }
 static inline void sev_es_shutdown_ghcb(void) { }
 static inline bool sev_es_check_ghcb_fault(unsigned long address)
 {
diff --git a/arch/x86/boot/compressed/sev.c b/arch/x86/boot/compressed/sev.c
index c93930d5ccbd0f1b4894012e09c885e20ee1ba0a..d63ad8f99f83a3c616f3560cd12f3ea03acbe049 100644
--- a/arch/x86/boot/compressed/sev.c
+++ b/arch/x86/boot/compressed/sev.c
@@ -208,6 +208,23 @@ void sev_es_shutdown_ghcb(void)
 		error("Can't unmap GHCB page");
 }
 
+static void __noreturn sev_es_ghcb_terminate(struct ghcb *ghcb, unsigned int set,
+					     unsigned int reason, u64 exit_info_2)
+{
+	u64 exit_info_1 = SVM_VMGEXIT_TERM_REASON(set, reason);
+
+	vc_ghcb_invalidate(ghcb);
+	ghcb_set_sw_exit_code(ghcb, SVM_VMGEXIT_TERM_REQUEST);
+	ghcb_set_sw_exit_info_1(ghcb, exit_info_1);
+	ghcb_set_sw_exit_info_2(ghcb, exit_info_2);
+
+	sev_es_wr_ghcb_msr(__pa(ghcb));
+	VMGEXIT();
+
+	while (true)
+		asm volatile("hlt\n" : : : "memory");
+}
+
 bool sev_es_check_ghcb_fault(unsigned long address)
 {
 	/* Check whether the fault was on the GHCB page */
@@ -270,6 +287,59 @@ static void enforce_vmpl0(void)
 		sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_NOT_VMPL0);
 }
 
+/*
+ * SNP_FEATURES_IMPL_REQ is the mask of SNP features that will need
+ * guest side implementation for proper functioning of the guest. If any
+ * of these features are enabled in the hypervisor but are lacking guest
+ * side implementation, the behavior of the guest will be undefined. The
+ * guest could fail in non-obvious way making it difficult to debug.
+ *
+ * As the behavior of reserved feature bits is unknown to be on the
+ * safe side add them to the required features mask.
+ */
+#define SNP_FEATURES_IMPL_REQ	(MSR_AMD64_SNP_VTOM |			\
+				 MSR_AMD64_SNP_REFLECT_VC |		\
+				 MSR_AMD64_SNP_RESTRICTED_INJ |		\
+				 MSR_AMD64_SNP_ALT_INJ |		\
+				 MSR_AMD64_SNP_DEBUG_SWAP |		\
+				 MSR_AMD64_SNP_VMPL_SSS |		\
+				 MSR_AMD64_SNP_SECURE_TSC |		\
+				 MSR_AMD64_SNP_VMGEXIT_PARAM |		\
+				 MSR_AMD64_SNP_VMSA_REG_PROTECTION |	\
+				 MSR_AMD64_SNP_RESERVED_BIT13 |		\
+				 MSR_AMD64_SNP_RESERVED_BIT15 |		\
+				 MSR_AMD64_SNP_RESERVED_MASK)
+
+/*
+ * SNP_FEATURES_PRESENT is the mask of SNP features that are implemented
+ * by the guest kernel. As and when a new feature is implemented in the
+ * guest kernel, a corresponding bit should be added to the mask.
+ */
+#define SNP_FEATURES_PRESENT (0)
+
+void snp_check_features(void)
+{
+	u64 unsupported;
+
+	if (!(sev_status & MSR_AMD64_SEV_SNP_ENABLED))
+		return;
+
+	/*
+	 * Terminate the boot if hypervisor has enabled any feature lacking
+	 * guest side implementation. Pass on the unsupported features mask through
+	 * EXIT_INFO_2 of the GHCB protocol so that those features can be reported
+	 * as part of the guest boot failure.
+	 */
+	unsupported = sev_status & SNP_FEATURES_IMPL_REQ & ~SNP_FEATURES_PRESENT;
+	if (unsupported) {
+		if (ghcb_version < 2 || (!boot_ghcb && !early_setup_ghcb()))
+			sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SNP_UNSUPPORTED);
+
+		sev_es_ghcb_terminate(boot_ghcb, SEV_TERM_SET_GEN,
+				      GHCB_SNP_UNSUPPORTED, unsupported);
+	}
+}
+
 void sev_enable(struct boot_params *bp)
 {
 	unsigned int eax, ebx, ecx, edx;
diff --git a/arch/x86/include/asm/acpi.h b/arch/x86/include/asm/acpi.h
index 65064d9f7fa6ead3835194be565b10bf26cfb909..8eb74cf386dbe5cac24c25fca9422a99212ab9b7 100644
--- a/arch/x86/include/asm/acpi.h
+++ b/arch/x86/include/asm/acpi.h
@@ -14,6 +14,7 @@
 #include <asm/mmu.h>
 #include <asm/mpspec.h>
 #include <asm/x86_init.h>
+#include <asm/cpufeature.h>
 
 #ifdef CONFIG_ACPI_APEI
 # include <asm/pgtable_types.h>
@@ -63,6 +64,13 @@ extern int (*acpi_suspend_lowlevel)(void);
 /* Physical address to resume after wakeup */
 unsigned long acpi_get_wakeup_address(void);
 
+static inline bool acpi_skip_set_wakeup_address(void)
+{
+	return cpu_feature_enabled(X86_FEATURE_XENPV);
+}
+
+#define acpi_skip_set_wakeup_address acpi_skip_set_wakeup_address
+
 /*
  * Check if the CPU can handle C2 and deeper
  */
diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h
index 37ff47552bcb7b57fdc75bc0246f2bb3876add4a..d3fe82c5d6b660d103788298d5f04a5a86a08104 100644
--- a/arch/x86/include/asm/msr-index.h
+++ b/arch/x86/include/asm/msr-index.h
@@ -566,6 +566,26 @@
 #define MSR_AMD64_SEV_ES_ENABLED	BIT_ULL(MSR_AMD64_SEV_ES_ENABLED_BIT)
 #define MSR_AMD64_SEV_SNP_ENABLED	BIT_ULL(MSR_AMD64_SEV_SNP_ENABLED_BIT)
 
+/* SNP feature bits enabled by the hypervisor */
+#define MSR_AMD64_SNP_VTOM			BIT_ULL(3)
+#define MSR_AMD64_SNP_REFLECT_VC		BIT_ULL(4)
+#define MSR_AMD64_SNP_RESTRICTED_INJ		BIT_ULL(5)
+#define MSR_AMD64_SNP_ALT_INJ			BIT_ULL(6)
+#define MSR_AMD64_SNP_DEBUG_SWAP		BIT_ULL(7)
+#define MSR_AMD64_SNP_PREVENT_HOST_IBS		BIT_ULL(8)
+#define MSR_AMD64_SNP_BTB_ISOLATION		BIT_ULL(9)
+#define MSR_AMD64_SNP_VMPL_SSS			BIT_ULL(10)
+#define MSR_AMD64_SNP_SECURE_TSC		BIT_ULL(11)
+#define MSR_AMD64_SNP_VMGEXIT_PARAM		BIT_ULL(12)
+#define MSR_AMD64_SNP_IBS_VIRT			BIT_ULL(14)
+#define MSR_AMD64_SNP_VMSA_REG_PROTECTION	BIT_ULL(16)
+#define MSR_AMD64_SNP_SMT_PROTECTION		BIT_ULL(17)
+
+/* SNP feature bits reserved for future use. */
+#define MSR_AMD64_SNP_RESERVED_BIT13		BIT_ULL(13)
+#define MSR_AMD64_SNP_RESERVED_BIT15		BIT_ULL(15)
+#define MSR_AMD64_SNP_RESERVED_MASK		GENMASK_ULL(63, 18)
+
 #define MSR_AMD64_VIRT_SPEC_CTRL	0xc001011f
 
 /* AMD Collaborative Processor Performance Control MSRs */
diff --git a/arch/x86/include/uapi/asm/svm.h b/arch/x86/include/uapi/asm/svm.h
index f69c168391aa58cf280ba6fb5aca6630e3593d1a..80e1df482337dfe064d809966a309cecd0930070 100644
--- a/arch/x86/include/uapi/asm/svm.h
+++ b/arch/x86/include/uapi/asm/svm.h
@@ -116,6 +116,12 @@
 #define SVM_VMGEXIT_AP_CREATE			1
 #define SVM_VMGEXIT_AP_DESTROY			2
 #define SVM_VMGEXIT_HV_FEATURES			0x8000fffd
+#define SVM_VMGEXIT_TERM_REQUEST		0x8000fffe
+#define SVM_VMGEXIT_TERM_REASON(reason_set, reason_code)	\
+	/* SW_EXITINFO1[3:0] */					\
+	(((((u64)reason_set) & 0xf)) |				\
+	/* SW_EXITINFO1[11:4] */				\
+	((((u64)reason_code) & 0xff) << 4))
 #define SVM_VMGEXIT_UNSUPPORTED_EVENT		0x8000ffff
 
 /* Exit code reserved for hypervisor/software use */
diff --git a/arch/x86/kernel/i8259.c b/arch/x86/kernel/i8259.c
index 3aa5304200c5073d380ddcbe240d49b09129fab2..4d8aff05a509ec4ca413b08e3d26ca812f5d94e7 100644
--- a/arch/x86/kernel/i8259.c
+++ b/arch/x86/kernel/i8259.c
@@ -114,6 +114,7 @@ static void make_8259A_irq(unsigned int irq)
 	disable_irq_nosync(irq);
 	io_apic_irqs &= ~(1<<irq);
 	irq_set_chip_and_handler(irq, &i8259A_chip, handle_level_irq);
+	irq_set_status_flags(irq, IRQ_LEVEL);
 	enable_irq(irq);
 	lapic_assign_legacy_vector(irq, true);
 }
diff --git a/arch/x86/kernel/irqinit.c b/arch/x86/kernel/irqinit.c
index beb1bada1b0ab2da5c5bd6d6b6ddde8ee6245d4b..c683666876f1c7026acf5b4d63b93381181e1801 100644
--- a/arch/x86/kernel/irqinit.c
+++ b/arch/x86/kernel/irqinit.c
@@ -65,8 +65,10 @@ void __init init_ISA_irqs(void)
 
 	legacy_pic->init(0);
 
-	for (i = 0; i < nr_legacy_irqs(); i++)
+	for (i = 0; i < nr_legacy_irqs(); i++) {
 		irq_set_chip_and_handler(i, chip, handle_level_irq);
+		irq_set_status_flags(i, IRQ_LEVEL);
+	}
 }
 
 void __init init_IRQ(void)
diff --git a/arch/x86/pci/xen.c b/arch/x86/pci/xen.c
index b94f727251b6436d3101cb6d0abe04c7fc13a660..8babce71915fe514aa24cfdb25f36c98ddc90369 100644
--- a/arch/x86/pci/xen.c
+++ b/arch/x86/pci/xen.c
@@ -392,6 +392,7 @@ static void xen_teardown_msi_irqs(struct pci_dev *dev)
 	msi_for_each_desc(msidesc, &dev->dev, MSI_DESC_ASSOCIATED) {
 		for (i = 0; i < msidesc->nvec_used; i++)
 			xen_destroy_irq(msidesc->irq + i);
+		msidesc->irq = 0;
 	}
 }
 
@@ -433,6 +434,7 @@ static struct msi_domain_ops xen_pci_msi_domain_ops = {
 };
 
 static struct msi_domain_info xen_pci_msi_domain_info = {
+	.flags			= MSI_FLAG_PCI_MSIX | MSI_FLAG_FREE_MSI_DESCS | MSI_FLAG_DEV_SYSFS,
 	.ops			= &xen_pci_msi_domain_ops,
 };
 
diff --git a/drivers/acpi/sleep.c b/drivers/acpi/sleep.c
index 0b557c0d405ef1945024374556ddaf7e831ea4a4..4ca667251272210ab1afe05b37f7caa43eec9fbe 100644
--- a/drivers/acpi/sleep.c
+++ b/drivers/acpi/sleep.c
@@ -60,13 +60,17 @@ static struct notifier_block tts_notifier = {
 	.priority	= 0,
 };
 
+#ifndef acpi_skip_set_wakeup_address
+#define acpi_skip_set_wakeup_address() false
+#endif
+
 static int acpi_sleep_prepare(u32 acpi_state)
 {
 #ifdef CONFIG_ACPI_SLEEP
 	unsigned long acpi_wakeup_address;
 
 	/* do we have a wakeup address for S2 and S3? */
-	if (acpi_state == ACPI_STATE_S3) {
+	if (acpi_state == ACPI_STATE_S3 && !acpi_skip_set_wakeup_address()) {
 		acpi_wakeup_address = acpi_get_wakeup_address();
 		if (!acpi_wakeup_address)
 			return -EFAULT;