linux-kernel - [PATCH v3] crypto: ccp: Sanitize sev_platform

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Message-Id: <20230110030745.34831-1-jarkko@profian.com>
Date:   Tue, 10 Jan 2023 03:07:45 +0000
From:   Jarkko Sakkinen <jarkko@...fian.com>
To:     Brijesh Singh <brijesh.singh@....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:     Jarkko Sakkinen <jarkko@...fian.com>,
        linux-crypto@...r.kernel.org (open list:AMD CRYPTOGRAPHIC COPROCESSOR
        (CCP) DRIVER - SE...), linux-kernel@...r.kernel.org (open list)
Subject: [PATCH v3] crypto: ccp: Sanitize sev_platform_init() error messages

The following functions end up calling sev_platform_init() or
__sev_platform_init_locked():

* sev_guest_init()
* sev_ioctl_do_pek_csr
* sev_ioctl_do_pdh_export()
* sev_ioctl_do_pek_import()
* sev_ioctl_do_pek_pdh_gen()
* sev_pci_init()

However, only sev_pci_init() prints out the failed command error code, and
even there, the error message does not specify which SEV command failed.

Address this by printing out the SEV command errors inside
__sev_platform_init_locked(), and differentiate between DF_FLUSH, INIT and
INIT_EX commands.  As a side-effect, @error can be removed from the
parameter list.

This extra information is particularly useful if firmware loading and/or
initialization is going to be made more robust, e.g. by allowing firmware
loading to be postponed.

Signed-off-by: Jarkko Sakkinen <jarkko@...fian.com>
---
v3:
* Address Tom Lendacky's feedback:
  https://lore.kernel.org/kvm/8bf6f179-eee7-fd86-7892-cdcd76e0762a@amd.com/

v2:
* Address David Rientjes's feedback:
  https://lore.kernel.org/all/6a16bbe4-4281-fb28-78c4-4ec44c8aa679@google.com/
* Remove @error.
* Remove "SEV_" prefix: it is obvious from context so no need to make klog
  line longer.
---
 drivers/crypto/ccp/sev-dev.c | 17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)

diff --git a/drivers/crypto/ccp/sev-dev.c b/drivers/crypto/ccp/sev-dev.c
index 06fc7156c04f..a231418a5f13 100644
--- a/drivers/crypto/ccp/sev-dev.c
+++ b/drivers/crypto/ccp/sev-dev.c
@@ -476,19 +476,21 @@ static int __sev_platform_init_locked(int *error)
 		dev_err(sev->dev, "SEV: retrying INIT command because of SECURE_DATA_INVALID error. Retrying once to reset PSP SEV state.");
 		rc = init_function(&psp_ret);
 	}
-	if (error)
-		*error = psp_ret;
-
-	if (rc)
+	if (rc) {
+		dev_err(sev->dev, "SEV: %s failed error %#x",
+			sev_init_ex_buffer ? "CMD_INIT_EX" : "CMD_INIT", psp_ret);
 		return rc;
+	}
 
 	sev->state = SEV_STATE_INIT;
 
 	/* Prepare for first SEV guest launch after INIT */
 	wbinvd_on_all_cpus();
-	rc = __sev_do_cmd_locked(SEV_CMD_DF_FLUSH, NULL, error);
-	if (rc)
+	rc = __sev_do_cmd_locked(SEV_CMD_DF_FLUSH, NULL, &psp_ret);
+	if (rc) {
+		dev_err(sev->dev, "SEV: CMD_DF_FLUSH failed error %#x", psp_ret);
 		return rc;
+	}
 
 	dev_dbg(sev->dev, "SEV firmware initialized\n");
 
@@ -1337,8 +1339,7 @@ void sev_pci_init(void)
 	/* Initialize the platform */
 	rc = sev_platform_init(&error);
 	if (rc)
-		dev_err(sev->dev, "SEV: failed to INIT error %#x, rc %d\n",
-			error, rc);
+		dev_err(sev->dev, "SEV: failed to INIT rc %d\n", rc);
 
 	return;
 
-- 
2.38.1