[PATCH 6.12.y 3/6] crypto: ccp - Register SNP panic notifier only if SNP is enabled

[Sasha Levin <sashal@kernel.org>]

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

[ Upstream commit 19860c3274fb209e36ebcba562dc5da301a53cb3 ]

Currently, the SNP panic notifier is registered on module initialization
regardless of whether SNP is being enabled or initialized.

Instead, register the SNP panic notifier only when SNP is actually
initialized and unregister the notifier when SNP is shutdown.

Reviewed-by: Dionna Glaze <dionnaglaze@google.com>
Reviewed-by: Alexey Kardashevskiy <aik@amd.com>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Ashish Kalra <ashish.kalra@amd.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Stable-dep-of: 08f0e65e784c ("crypto: ccp - Do not initialize SNP for ioctl(SNP_CONFIG)")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/crypto/ccp/sev-dev.c | 22 +++++++++++++---------
 1 file changed, 13 insertions(+), 9 deletions(-)

diff --git a/drivers/crypto/ccp/sev-dev.c b/drivers/crypto/ccp/sev-dev.c
index 0a3ee7e05af2c5..12382f2405608f 100644
--- a/drivers/crypto/ccp/sev-dev.c
+++ b/drivers/crypto/ccp/sev-dev.c
@@ -105,6 +105,13 @@ static void *sev_init_ex_buffer;
 
 static void __sev_firmware_shutdown(struct sev_device *sev, bool panic);
 
+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;
@@ -1195,6 +1202,9 @@ 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;
@@ -1791,6 +1801,9 @@ 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;
 
@@ -2486,10 +2499,6 @@ 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)
 {
@@ -2535,8 +2544,6 @@ void sev_pci_init(void)
 		dev_err(sev->dev, "SEV: failed to INIT error %#x, rc %d\n",
 			args.error, rc);
 
-	atomic_notifier_chain_register(&panic_notifier_list,
-				       &snp_panic_notifier);
 	return;
 
 err:
@@ -2553,7 +2560,4 @@ void sev_pci_exit(void)
 		return;
 
 	sev_firmware_shutdown(sev);
-
-	atomic_notifier_chain_unregister(&panic_notifier_list,
-					 &snp_panic_notifier);
 }
-- 
2.53.0