linux-kernel - [PATCH v2 9/9] crypto: ccp: Move SEV/SNP Platform initialization to KVM

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Message-ID: <f7129ef82e622ce52b194ab017fee9b1881b0cc8.1734392473.git.ashish.kalra@amd.com>
Date: Tue, 17 Dec 2024 00:00:26 +0000
From: Ashish Kalra <Ashish.Kalra@....com>
To: <seanjc@...gle.com>, <pbonzini@...hat.com>, <tglx@...utronix.de>,
	<mingo@...hat.com>, <bp@...en8.de>, <dave.hansen@...ux.intel.com>,
	<x86@...nel.org>, <hpa@...or.com>, <thomas.lendacky@....com>,
	<john.allen@....com>, <herbert@...dor.apana.org.au>, <davem@...emloft.net>
CC: <michael.roth@....com>, <dionnaglaze@...gle.com>, <kvm@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>, <linux-crypto@...r.kernel.org>,
	<linux-coco@...ts.linux.dev>
Subject: [PATCH v2 9/9] crypto: ccp: Move SEV/SNP Platform initialization to KVM

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

SNP initialization is forced during PSP driver probe purely because SNP
can't be initialized if VMs are running.  But the only in-tree user of
SEV/SNP functionality is KVM, and KVM depends on PSP driver for the same.
Forcing SEV/SNP initialization because a hypervisor could be running
legacy non-confidential VMs make no sense.

This patch removes SEV/SNP initialization from the PSP driver probe
time and moves the requirement to initialize SEV/SNP functionality
to KVM if it wants to use SEV/SNP.

Remove the psp_init_on_probe parameter as it not used anymore.
Remove the probe field from struct sev_platform_init_args as it is
not used anymore.
Remove _sev_platform_init_locked() as it not used anymore and to
support separate SNP and SEV initialization sev_platform_init() is
now modified to do only SEV initialization and call
__sev_platform_init_locked() directly.

Signed-off-by: Ashish Kalra <ashish.kalra@....com>
---
 drivers/crypto/ccp/sev-dev.c | 55 +-----------------------------------
 include/linux/psp-sev.h      |  4 ---
 2 files changed, 1 insertion(+), 58 deletions(-)

diff --git a/drivers/crypto/ccp/sev-dev.c b/drivers/crypto/ccp/sev-dev.c
index 53c438b2b712..fbae688e4b7d 100644
--- a/drivers/crypto/ccp/sev-dev.c
+++ b/drivers/crypto/ccp/sev-dev.c
@@ -69,10 +69,6 @@ static char *init_ex_path;
 module_param(init_ex_path, charp, 0444);
 MODULE_PARM_DESC(init_ex_path, " Path for INIT_EX data; if set try INIT_EX");
 
-static bool psp_init_on_probe = true;
-module_param(psp_init_on_probe, bool, 0444);
-MODULE_PARM_DESC(psp_init_on_probe, "  if true, the PSP will be initialized on module init. Else the PSP will be initialized on the first command requiring it");
-
 MODULE_FIRMWARE("amd/amd_sev_fam17h_model0xh.sbin"); /* 1st gen EPYC */
 MODULE_FIRMWARE("amd/amd_sev_fam17h_model3xh.sbin"); /* 2nd gen EPYC */
 MODULE_FIRMWARE("amd/amd_sev_fam19h_model0xh.sbin"); /* 3rd gen EPYC */
@@ -1329,46 +1325,12 @@ static int __sev_platform_init_locked(int *error)
 	return rc;
 }
 
-static int _sev_platform_init_locked(struct sev_platform_init_args *args)
-{
-	struct sev_device *sev;
-	int rc;
-
-	if (!psp_master || !psp_master->sev_data)
-		return -ENODEV;
-
-	sev = psp_master->sev_data;
-
-	if (sev->state == SEV_STATE_INIT)
-		return 0;
-
-	/*
-	 * Legacy guests cannot be running while SNP_INIT(_EX) is executing,
-	 * so perform SEV-SNP initialization at probe time.
-	 */
-	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);
-	}
-
-	/* Defer legacy SEV/SEV-ES support if allowed by caller/module. */
-	if (args->probe && !psp_init_on_probe)
-		return 0;
-
-	return __sev_platform_init_locked(&args->error);
-}
-
 int sev_platform_init(struct sev_platform_init_args *args)
 {
 	int rc;
 
 	mutex_lock(&sev_cmd_mutex);
-	rc = _sev_platform_init_locked(args);
+	rc = __sev_platform_init_locked(&args->error);
 	mutex_unlock(&sev_cmd_mutex);
 
 	return rc;
@@ -2556,9 +2518,7 @@ EXPORT_SYMBOL_GPL(sev_issue_cmd_external_user);
 void sev_pci_init(void)
 {
 	struct sev_device *sev = psp_master->sev_data;
-	struct sev_platform_init_args args = {0};
 	u8 api_major, api_minor, build;
-	int rc;
 
 	if (!sev)
 		return;
@@ -2581,16 +2541,6 @@ void sev_pci_init(void)
 			 api_major, api_minor, build,
 			 sev->api_major, sev->api_minor, sev->build);
 
-	/* Initialize the platform */
-	args.probe = true;
-	rc = sev_platform_init(&args);
-	if (rc)
-		dev_err(sev->dev, "SEV: failed to INIT error %#x, rc %d\n",
-			args.error, rc);
-
-	dev_info(sev->dev, "SEV%s API:%d.%d build:%d\n", sev->snp_initialized ?
-		"-SNP" : "", sev->api_major, sev->api_minor, sev->build);
-
 	return;
 
 err:
@@ -2605,7 +2555,4 @@ void sev_pci_exit(void)
 
 	if (!sev)
 		return;
-
-	sev_firmware_shutdown(sev);
-
 }
diff --git a/include/linux/psp-sev.h b/include/linux/psp-sev.h
index e50643aef8a9..dec89fc0b356 100644
--- a/include/linux/psp-sev.h
+++ b/include/linux/psp-sev.h
@@ -794,13 +794,9 @@ struct sev_data_snp_shutdown_ex {
  * struct sev_platform_init_args
  *
  * @error: SEV firmware error code
- * @probe: True if this is being called as part of CCP module probe, which
- *  will defer SEV_INIT/SEV_INIT_EX firmware initialization until needed
- *  unless psp_init_on_probe module param is set
  */
 struct sev_platform_init_args {
 	int error;
-	bool probe;
 };
 
 /**
-- 
2.34.1