linux-kernel - [PATCH 4/7] crypto: ccp: Register SNP panic notifier only if SNP is enabled

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Message-ID: <cf956c36ee9f89a5273cbccd55e2ab50855d754f.1733785468.git.ashish.kalra@amd.com>
Date: Mon, 9 Dec 2024 23:25:47 +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 4/7] crypto: ccp: Register SNP panic notifier only if SNP is enabled

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

Register the SNP panic notifier if and only if SNP is actually
initialized and deregistering the notifier when shutting down
SNP in PSP driver when KVM module is unloaded.

Signed-off-by: Ashish Kalra <ashish.kalra@....com>
---
 drivers/crypto/ccp/sev-dev.c | 21 +++++++++++++--------
 1 file changed, 13 insertions(+), 8 deletions(-)

diff --git a/drivers/crypto/ccp/sev-dev.c b/drivers/crypto/ccp/sev-dev.c
index bc121ad9ec26..21faf4c4c4ec 100644
--- a/drivers/crypto/ccp/sev-dev.c
+++ b/drivers/crypto/ccp/sev-dev.c
@@ -109,6 +109,13 @@ static void *sev_init_ex_buffer;
  */
 static struct sev_data_range_list *snp_range_list;
 
+static int snp_shutdown_on_panic(struct notifier_block *nb,
+				 unsigned long reason, void *arg);
+
+static struct notifier_block snp_panic_notifier = {
+	.notifier_call = snp_shutdown_on_panic,
+};
+
 static inline bool sev_version_greater_or_equal(u8 maj, u8 min)
 {
 	struct sev_device *sev = psp_master->sev_data;
@@ -1191,6 +1198,9 @@ static int __sev_snp_init_locked(int *error)
 	dev_info(sev->dev, "SEV-SNP API:%d.%d build:%d\n", sev->api_major,
 		 sev->api_minor, sev->build);
 
+	atomic_notifier_chain_register(&panic_notifier_list,
+				       &snp_panic_notifier);
+
 	sev_es_tmr_size = SNP_TMR_SIZE;
 
 	return 0;
@@ -1750,6 +1760,9 @@ static int __sev_snp_shutdown_locked(int *error, bool panic)
 	sev->snp_initialized = false;
 	dev_dbg(sev->dev, "SEV-SNP firmware shutdown\n");
 
+	atomic_notifier_chain_unregister(&panic_notifier_list,
+					 &snp_panic_notifier);
+
 	/* Reset TMR size back to default */
 	sev_es_tmr_size = SEV_TMR_SIZE;
 
@@ -2489,10 +2502,6 @@ static int snp_shutdown_on_panic(struct notifier_block *nb,
 	return NOTIFY_DONE;
 }
 
-static struct notifier_block snp_panic_notifier = {
-	.notifier_call = snp_shutdown_on_panic,
-};
-
 int sev_issue_cmd_external_user(struct file *filep, unsigned int cmd,
 				void *data, int *error)
 {
@@ -2541,8 +2550,6 @@ void sev_pci_init(void)
 	dev_info(sev->dev, "SEV%s API:%d.%d build:%d\n", sev->snp_initialized ?
 		"-SNP" : "", sev->api_major, sev->api_minor, sev->build);
 
-	atomic_notifier_chain_register(&panic_notifier_list,
-				       &snp_panic_notifier);
 	return;
 
 err:
@@ -2560,6 +2567,4 @@ void sev_pci_exit(void)
 
 	sev_firmware_shutdown(sev);
 
-	atomic_notifier_chain_unregister(&panic_notifier_list,
-					 &snp_panic_notifier);
 }
-- 
2.34.1