linux-kernel - [PATCH v3] crypto: ccp: Abort doing SEV INIT if SNP INIT fails

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Message-ID: <20250318210651.7616-1-Ashish.Kalra@amd.com>
Date: Tue, 18 Mar 2025 21:06:51 +0000
From: Ashish Kalra <Ashish.Kalra@....com>
To: <seanjc@...gle.com>, <pbonzini@...hat.com>, <bp@...en8.de>,
	<thomas.lendacky@....com>, <john.allen@....com>,
	<herbert@...dor.apana.org.au>, <davem@...emloft.net>
CC: <michael.roth@....com>, <kvm@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>, <linux-crypto@...r.kernel.org>,
	<linux-coco@...ts.linux.dev>
Subject: [PATCH v3] crypto: ccp: Abort doing SEV INIT if SNP INIT fails

From: Ashish Kalra <ashish.kalra@....com>

If SNP host support (SYSCFG.SNPEn) is set, then the RMP table must
be initialized before calling SEV INIT.

In other words, if SNP_INIT(_EX) is not issued or fails then
SEV INIT will fail if SNP host support (SYSCFG.SNPEn) is enabled.

v3:
- Drop the Fixes: tag as continuing with SEV INIT after SNP INIT(_EX)
failure will still cause SEV INIT to fail, we are simply aborting
here after SNP INIT(_EX) failure.

v2:
- Fix commit logs.

Signed-off-by: Ashish Kalra <ashish.kalra@....com>
---
 drivers/crypto/ccp/sev-dev.c | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/drivers/crypto/ccp/sev-dev.c b/drivers/crypto/ccp/sev-dev.c
index 2e87ca0e292a..a0e3de94704e 100644
--- a/drivers/crypto/ccp/sev-dev.c
+++ b/drivers/crypto/ccp/sev-dev.c
@@ -1112,7 +1112,7 @@ static int __sev_snp_init_locked(int *error)
 	if (!sev_version_greater_or_equal(SNP_MIN_API_MAJOR, SNP_MIN_API_MINOR)) {
 		dev_dbg(sev->dev, "SEV-SNP support requires firmware version >= %d:%d\n",
 			SNP_MIN_API_MAJOR, SNP_MIN_API_MINOR);
-		return 0;
+		return -EOPNOTSUPP;
 	}
 
 	/* SNP_INIT requires MSR_VM_HSAVE_PA to be cleared on all CPUs. */
@@ -1325,12 +1325,9 @@ static int _sev_platform_init_locked(struct sev_platform_init_args *args)
 	 */
 	rc = __sev_snp_init_locked(&args->error);
 	if (rc && rc != -ENODEV) {
-		/*
-		 * Don't abort the probe if SNP INIT failed,
-		 * continue to initialize the legacy SEV firmware.
-		 */
 		dev_err(sev->dev, "SEV-SNP: failed to INIT rc %d, error %#x\n",
 			rc, args->error);
+		return rc;
 	}
 
 	/* Defer legacy SEV/SEV-ES support if allowed by caller/module. */
-- 
2.34.1