linux-kernel - [PATCH 1/2] crypto: ccp - Fix a case where SNP

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Message-ID: <20260105172218.39993-1-tycho@kernel.org>
Date: Mon,  5 Jan 2026 10:22:17 -0700
From: Tycho Andersen <tycho@...nel.org>
To: Ashish Kalra <ashish.kalra@....com>,
	Tom Lendacky <thomas.lendacky@....com>,
	John Allen <john.allen@....com>,
	Herbert Xu <herbert@...dor.apana.org.au>,
	"David S . Miller" <davem@...emloft.net>
Cc: linux-crypto@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	"Tycho Andersen (AMD)" <tycho@...nel.org>,
	Alexey Kardashevskiy <aik@....com>
Subject: [PATCH 1/2] crypto: ccp - Fix a case where SNP_SHUTDOWN is missed

From: Tom Lendacky <thomas.lendacky@....com>

If page reclaim fails in sev_ioctl_do_snp_platform_status() and SNP was
moved from UNINIT to INIT for the function, SNP is not moved back to
UNINIT state. Additionally, SNP is not required to be initialized in order
to execute the SNP_PLATFORM_STATUS command, so don't attempt to move to
INIT state and let SNP_PLATFORM_STATUS report the status as is.

Fixes: ceac7fb89e8d ("crypto: ccp - Ensure implicit SEV/SNP init and shutdown in ioctls")
Signed-off-by: Tom Lendacky <thomas.lendacky@....com>
Reviewed-by: Tycho Andersen (AMD) <tycho@...nel.org>
Reviewed-by: Alexey Kardashevskiy <aik@....com>
Signed-off-by: Tycho Andersen (AMD) <tycho@...nel.org>
---
 drivers/crypto/ccp/sev-dev.c | 46 ++++++++++++++++++------------------
 1 file changed, 23 insertions(+), 23 deletions(-)

diff --git a/drivers/crypto/ccp/sev-dev.c b/drivers/crypto/ccp/sev-dev.c
index 956ea609d0cc..6e6011e363e3 100644
--- a/drivers/crypto/ccp/sev-dev.c
+++ b/drivers/crypto/ccp/sev-dev.c
@@ -2378,11 +2378,10 @@ static int sev_ioctl_do_pdh_export(struct sev_issue_cmd *argp, bool writable)
 static int sev_ioctl_do_snp_platform_status(struct sev_issue_cmd *argp)
 {
 	struct sev_device *sev = psp_master->sev_data;
-	bool shutdown_required = false;
 	struct sev_data_snp_addr buf;
 	struct page *status_page;
-	int ret, error;
 	void *data;
+	int ret;
 
 	if (!argp->data)
 		return -EINVAL;
@@ -2393,31 +2392,35 @@ static int sev_ioctl_do_snp_platform_status(struct sev_issue_cmd *argp)
 
 	data = page_address(status_page);
 
-	if (!sev->snp_initialized) {
-		ret = snp_move_to_init_state(argp, &shutdown_required);
-		if (ret)
-			goto cleanup;
-	}
-
 	/*
-	 * Firmware expects status page to be in firmware-owned state, otherwise
-	 * it will report firmware error code INVALID_PAGE_STATE (0x1A).
+	 * SNP_PLATFORM_STATUS can be executed in any SNP state. But if executed
+	 * when SNP has been initialized, the status page must be firmware-owned.
 	 */
-	if (rmp_mark_pages_firmware(__pa(data), 1, true)) {
-		ret = -EFAULT;
-		goto cleanup;
+	if (sev->snp_initialized) {
+		/*
+		 * Firmware expects the status page to be in Firmware state,
+		 * otherwise it will report an error INVALID_PAGE_STATE.
+		 */
+		if (rmp_mark_pages_firmware(__pa(data), 1, true)) {
+			ret = -EFAULT;
+			goto cleanup;
+		}
 	}
 
 	buf.address = __psp_pa(data);
 	ret = __sev_do_cmd_locked(SEV_CMD_SNP_PLATFORM_STATUS, &buf, &argp->error);
 
-	/*
-	 * Status page will be transitioned to Reclaim state upon success, or
-	 * left in Firmware state in failure. Use snp_reclaim_pages() to
-	 * transition either case back to Hypervisor-owned state.
-	 */
-	if (snp_reclaim_pages(__pa(data), 1, true))
-		return -EFAULT;
+	if (sev->snp_initialized) {
+		/*
+		 * The status page will be in Reclaim state on success, or left
+		 * in Firmware state on failure. Use snp_reclaim_pages() to
+		 * transition either case back to Hypervisor-owned state.
+		 */
+		if (snp_reclaim_pages(__pa(data), 1, true)) {
+			snp_leak_pages(__page_to_pfn(status_page), 1);
+			return -EFAULT;
+		}
+	}
 
 	if (ret)
 		goto cleanup;
@@ -2427,9 +2430,6 @@ static int sev_ioctl_do_snp_platform_status(struct sev_issue_cmd *argp)
 		ret = -EFAULT;
 
 cleanup:
-	if (shutdown_required)
-		__sev_snp_shutdown_locked(&error, false);
-
 	__free_pages(status_page, 0);
 	return ret;
 }

base-commit: 3609fa95fb0f2c1b099e69e56634edb8fc03f87c
-- 
2.52.0