Re: [PATCH v5 4/7] crypto: ccp: Register SNP panic notifier only if SNP is enabled

Tom Lendacky
2025-03-03T14:56:34Z

On 2/25/25 15:00, Ashish Kalra wrote:
> From: Ashish Kalra <ashish.kalra@amd.com>
>
> 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>
> Signed-off-by: Ashish Kalra <ashish.kalra@amd.com>

Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>

> ---
> 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 c784de6c77c3..b3479a2896d0 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;
> @@ -1198,6 +1205,9 @@ 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;
> @@ -1754,6 +1764,9 @@ 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;
>
> @@ -2481,10 +2494,6 @@ 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)
> {
> @@ -2533,8 +2542,6 @@ 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:
> @@ -2551,7 +2558,4 @@ void sev_pci_exit(void)
> return;
>
> sev_firmware_shutdown(sev);
> -
> - atomic_notifier_chain_unregister(&panic_notifier_list,
> - &snp_panic_notifier);
> }