linux-kernel - [PATCH v3 4/7] crypto: ccp: Register SNP panic notifier only if SNP is enabled

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Message-ID: <674affc649968994f95b6259f162d5f0732b102c.1735931639.git.ashish.kalra@amd.com>
Date: Fri, 3 Jan 2025 20:00:59 +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 v3 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.

Currently the SNP panic notifier is being registered
irrespective of SNP being enabled/initialized and with this
change the SNP panic notifier is registered only if SNP
support is enabled and initialized.

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 9632a9a5c92e..7c15dec55f58 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;
@@ -1751,6 +1761,9 @@ 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;
 
@@ -2490,10 +2503,6 @@ 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)
 {
@@ -2542,8 +2551,6 @@ 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:
@@ -2561,6 +2568,4 @@ void sev_pci_exit(void)
 
 	sev_firmware_shutdown(sev);
 
-	atomic_notifier_chain_unregister(&panic_notifier_list,
-					 &snp_panic_notifier);
 }
-- 
2.34.1