diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
index 319a40fc57ce..f42cd5a8e7bb 100644
--- a/arch/x86/kernel/sev.c
+++ b/arch/x86/kernel/sev.c
@@ -51,6 +51,8 @@ static struct ghcb boot_ghcb_page __bss_decrypted __aligned(PAGE_SIZE);
  */
 static struct ghcb __initdata *boot_ghcb;
 
+static u64 snp_secrets_phys;
+
 /* #VC handler runtime per-CPU data */
 struct sev_es_runtime_data {
 	struct ghcb ghcb_page;
@@ -2030,6 +2032,80 @@ bool __init handle_vc_boot_ghcb(struct pt_regs *regs)
 		halt();
 }
 
+static struct snp_secrets_page_layout *snp_map_secrets_page(void)
+{
+	u16 __iomem *secrets;
+
+	if (!snp_secrets_phys || !sev_feature_enabled(SEV_SNP))
+		return NULL;
+
+	secrets = ioremap_encrypted(snp_secrets_phys, PAGE_SIZE);
+	if (!secrets)
+		return NULL;
+
+	return (struct snp_secrets_page_layout *)secrets;
+}
+
+static inline u64 snp_read_msg_seqno(void)
+{
+	struct snp_secrets_page_layout *layout;
+	u64 count;
+
+	layout = snp_map_secrets_page();
+	if (!layout)
+		return 0;
+
+	/* Read the current message sequence counter from secrets pages */
+	count = readl(&layout->os_area.msg_seqno_0);
+
+	iounmap(layout);
+
+	/* The sequence counter must begin with 1 */
+	if (!count)
+		return 1;
+
+	return count + 1;
+}
+
+u64 snp_msg_seqno(void)
+{
+	u64 count = snp_read_msg_seqno();
+
+	if (unlikely(!count))
+		return 0;
+
+	/*
+	 * The message sequence counter for the SNP guest request is a
+	 * 64-bit value but the version 2 of GHCB specification defines a
+	 * 32-bit storage for the it.
+	 */
+	if (count >= UINT_MAX)
+		return 0;
+
+	return count;
+}
+EXPORT_SYMBOL_GPL(snp_msg_seqno);
+
+static void snp_gen_msg_seqno(void)
+{
+	struct snp_secrets_page_layout *layout;
+	u64 count;
+
+	layout = snp_map_secrets_page();
+	if (!layout)
+		return;
+
+	/*
+	 * The counter is also incremented by the PSP, so increment it by 2
+	 * and save in secrets page.
+	 */
+	count = readl(&layout->os_area.msg_seqno_0);
+	count += 2;
+
+	writel(count, &layout->os_area.msg_seqno_0);
+	iounmap(layout);
+}
+
 int snp_issue_guest_request(int type, struct snp_guest_request_data *input, unsigned long *fw_err)
 {
 	struct ghcb_state state;
@@ -2077,6 +2153,9 @@ int snp_issue_guest_request(int type, struct snp_guest_request_data *input, unsi
 		ret = -EIO;
 	}
 
+	/* The command was successful, increment the sequence counter */
+	snp_gen_msg_seqno();
+
 e_put:
 	__sev_put_ghcb(&state);
 e_restore_irq:
diff --git a/include/linux/sev-guest.h b/include/linux/sev-guest.h
index 24dd17507789..16b6af24fda7 100644
--- a/include/linux/sev-guest.h
+++ b/include/linux/sev-guest.h
@@ -20,6 +20,41 @@ enum vmgexit_type {
 	GUEST_REQUEST_MAX
 };
 
+/*
+ * The secrets page contains 96-bytes of reserved field that can be used by
+ * the guest OS. The guest OS uses the area to save the message sequence
+ * number for each VMPCK.
+ *
+ * See the GHCB spec section Secret page layout for the format for this area.
+ */
+struct secrets_os_area {
+	u32 msg_seqno_0;
+	u32 msg_seqno_1;
+	u32 msg_seqno_2;
+	u32 msg_seqno_3;
+	u64 ap_jump_table_pa;
+	u8 rsvd[40];
+	u8 guest_usage[32];
+} __packed;
+
+#define VMPCK_KEY_LEN		32
+
+/* See the SNP spec for secrets page format */
+struct snp_secrets_page_layout {
+	u32 version;
+	u32 imien	: 1,
+	    rsvd1	: 31;
+	u32 fms;
+	u32 rsvd2;
+	u8 gosvw[16];
+	u8 vmpck0[VMPCK_KEY_LEN];
+	u8 vmpck1[VMPCK_KEY_LEN];
+	u8 vmpck2[VMPCK_KEY_LEN];
+	u8 vmpck3[VMPCK_KEY_LEN];
+	struct secrets_os_area os_area;
+	u8 rsvd3[3840];
+} __packed;
+
 /*
  * The error code when the data_npages is too small. The error code
  * is defined in the GHCB specification.
@@ -36,6 +71,7 @@ struct snp_guest_request_data {
 #ifdef CONFIG_AMD_MEM_ENCRYPT
 int snp_issue_guest_request(int vmgexit_type, struct snp_guest_request_data *input,
 			    unsigned long *fw_err);
+u64 snp_msg_seqno(void);
 #else
 
 static inline int snp_issue_guest_request(int type, struct snp_guest_request_data *input,
@@ -43,6 +79,7 @@ static inline int snp_issue_guest_request(int type, struct snp_guest_request_dat
 {
 	return -ENODEV;
 }
+static inline u64 snp_msg_seqno(void) { return 0; }
 
 #endif /* CONFIG_AMD_MEM_ENCRYPT */
 #endif /* __LINUX_SEV_GUEST_H__ */
