diff --git a/arch/x86/include/asm/sev-common.h b/arch/x86/include/asm/sev-common.h
index 1e6fb93d8ab0..93ec8c12c91d 100644
--- a/arch/x86/include/asm/sev-common.h
+++ b/arch/x86/include/asm/sev-common.h
@@ -173,8 +173,22 @@ struct snp_psc_desc {
 #define GHCB_ERR_INVALID_INPUT		5
 #define GHCB_ERR_INVALID_EVENT		6
 
+/* RMUPDATE detected 4K page and 2MB page overlap. */
+#define RMPUPDATE_FAIL_OVERLAP		4
+
 /* RMP page size */
 #define RMP_PG_SIZE_4K			0
+#define RMP_PG_SIZE_2M			1
 #define RMP_TO_X86_PG_LEVEL(level)	(((level) == RMP_PG_SIZE_4K) ? PG_LEVEL_4K : PG_LEVEL_2M)
+#define X86_TO_RMP_PG_LEVEL(level)	(((level) == PG_LEVEL_4K) ? RMP_PG_SIZE_4K : RMP_PG_SIZE_2M)
+
+struct rmp_state {
+	u64 gpa;
+	u8 assigned;
+	u8 pagesize;
+	u8 immutable;
+	u8 rsvd;
+	u32 asid;
+} __packed;
 
 #endif
diff --git a/arch/x86/include/asm/sev-host.h b/arch/x86/include/asm/sev-host.h
index bb06c57f2909..1df989411334 100644
--- a/arch/x86/include/asm/sev-host.h
+++ b/arch/x86/include/asm/sev-host.h
@@ -16,9 +16,19 @@
 #ifdef CONFIG_KVM_AMD_SEV
 int snp_lookup_rmpentry(u64 pfn, bool *assigned, int *level);
 void sev_dump_hva_rmpentry(unsigned long address);
+int psmash(u64 pfn);
+int rmp_make_private(u64 pfn, u64 gpa, enum pg_level level, int asid, bool immutable);
+int rmp_make_shared(u64 pfn, enum pg_level level);
 #else
 static inline int snp_lookup_rmpentry(u64 pfn, bool *assigned, int *level) { return -ENXIO; }
 static inline void sev_dump_hva_rmpentry(unsigned long address) {}
+static inline int psmash(u64 pfn) { return -ENXIO; }
+static inline int rmp_make_private(u64 pfn, u64 gpa, enum pg_level level, int asid,
+				   bool immutable)
+{
+	return -ENXIO;
+}
+static inline int rmp_make_shared(u64 pfn, enum pg_level level) { return -ENXIO; }
 #endif
 
 #endif
diff --git a/arch/x86/virt/svm/sev.c b/arch/x86/virt/svm/sev.c
index cac3e311c38f..24a695af13a5 100644
--- a/arch/x86/virt/svm/sev.c
+++ b/arch/x86/virt/svm/sev.c
@@ -367,3 +367,92 @@ void sev_dump_hva_rmpentry(unsigned long hva)
 	sev_dump_rmpentry(pte_pfn(*pte));
 }
 EXPORT_SYMBOL_GPL(sev_dump_hva_rmpentry);
+
+/*
+ * PSMASH a 2MB aligned page into 4K pages in the RMP table while preserving the
+ * Validated bit.
+ */
+int psmash(u64 pfn)
+{
+	unsigned long paddr = pfn << PAGE_SHIFT;
+	int ret;
+
+	pr_debug("%s: PFN: 0x%llx\n", __func__, pfn);
+
+	if (!pfn_valid(pfn))
+		return -EINVAL;
+
+	if (!cpu_feature_enabled(X86_FEATURE_SEV_SNP))
+		return -ENXIO;
+
+	/* Binutils version 2.36 supports the PSMASH mnemonic. */
+	asm volatile(".byte 0xF3, 0x0F, 0x01, 0xFF"
+		      : "=a"(ret)
+		      : "a"(paddr)
+		      : "memory", "cc");
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(psmash);
+
+static int rmpupdate(u64 pfn, struct rmp_state *val)
+{
+	unsigned long paddr = pfn << PAGE_SHIFT;
+	int ret, level, npages;
+	int attempts = 0;
+
+	if (!cpu_feature_enabled(X86_FEATURE_SEV_SNP))
+		return -ENXIO;
+
+	do {
+		/* Binutils version 2.36 supports the RMPUPDATE mnemonic. */
+		asm volatile(".byte 0xF2, 0x0F, 0x01, 0xFE"
+			     : "=a"(ret)
+			     : "a"(paddr), "c"((unsigned long)val)
+			     : "memory", "cc");
+
+		attempts++;
+	} while (ret == RMPUPDATE_FAIL_OVERLAP);
+
+	if (ret) {
+		pr_err("RMPUPDATE failed after %d attempts, ret: %d, pfn: %llx, npages: %d, level: %d\n",
+		       attempts, ret, pfn, npages, level);
+		sev_dump_rmpentry(pfn);
+		dump_stack();
+		return -EFAULT;
+	}
+
+	return 0;
+}
+
+/*
+ * Assign a page to guest using the RMPUPDATE instruction.
+ */
+int rmp_make_private(u64 pfn, u64 gpa, enum pg_level level, int asid, bool immutable)
+{
+	struct rmp_state val;
+
+	memset(&val, 0, sizeof(val));
+	val.assigned = 1;
+	val.asid = asid;
+	val.immutable = immutable;
+	val.gpa = gpa;
+	val.pagesize = X86_TO_RMP_PG_LEVEL(level);
+
+	return rmpupdate(pfn, &val);
+}
+EXPORT_SYMBOL_GPL(rmp_make_private);
+
+/*
+ * Transition a page to hypervisor/shared state using the RMPUPDATE instruction.
+ */
+int rmp_make_shared(u64 pfn, enum pg_level level)
+{
+	struct rmp_state val;
+
+	memset(&val, 0, sizeof(val));
+	val.pagesize = X86_TO_RMP_PG_LEVEL(level);
+
+	return rmpupdate(pfn, &val);
+}
+EXPORT_SYMBOL_GPL(rmp_make_shared);
