Re: [Patch v4 4/7] crypto: ccp - Factor out the release of the SEV firmware buffers

[Tom Lendacky]

On 10/14/26 21:14, Pratik R. Sampat wrote:
> __sev_firmware_shutdown() reclaims and frees the TMR and the INIT_EX NV
> area once the platform has been taken down. Move that into a helper so
> that other paths which de-initialize the platform can reuse the same
> path.
> 
> No functional change intended.
> 
> Suggested-by: Shantanu Sinha <shansinha@xxxxxxxxxx>
> Signed-off-by: Pratik R. Sampat <prsampat@xxxxxxx>

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

> ---
> v3..v4:
> No change
> ---
>  drivers/crypto/ccp/sev-dev.c | 55 ++++++++++++++++++++----------------
>  1 file changed, 30 insertions(+), 25 deletions(-)
> 
> diff --git a/drivers/crypto/ccp/sev-dev.c b/drivers/crypto/ccp/sev-dev.c
> index f833cb7e4da3..1ed9e61a95cc 100644
> --- a/drivers/crypto/ccp/sev-dev.c
> +++ b/drivers/crypto/ccp/sev-dev.c
> @@ -1881,6 +1881,35 @@ static int __sev_platform_shutdown_locked(int *error)
>  	return ret;
>  }
>  
> +static void __sev_release_firmware_buffers(bool panic)
> +{
> +	if (sev_es_tmr) {
> +		/*
> +		 * The TMR area was encrypted, flush it from the cache.
> +		 *
> +		 * If invoked during panic handling, local interrupts are
> +		 * disabled and all CPUs are stopped, so wbinvd_on_all_cpus()
> +		 * can't be used. In that case, wbinvd() is done on remote CPUs
> +		 * via the NMI callback, and done for this CPU later during
> +		 * SNP shutdown, so wbinvd_on_all_cpus() can be skipped.
> +		 */
> +		if (!panic)
> +			wbinvd_on_all_cpus();
> +
> +		__snp_free_firmware_pages(virt_to_page(sev_es_tmr),
> +					  get_order(sev_es_tmr_size),
> +					  true);
> +		sev_es_tmr = NULL;
> +	}
> +
> +	if (sev_init_ex_buffer) {
> +		__snp_free_firmware_pages(virt_to_page(sev_init_ex_buffer),
> +					  get_order(NV_LENGTH),
> +					  true);
> +		sev_init_ex_buffer = NULL;
> +	}
> +}
> +
>  static int sev_get_platform_state(int *state, int *error)
>  {
>  	struct sev_user_data_status data;
> @@ -2906,31 +2935,7 @@ static void __sev_firmware_shutdown(struct sev_device *sev, bool panic)
>  
>  	__sev_platform_shutdown_locked(&error);
>  
> -	if (sev_es_tmr) {
> -		/*
> -		 * The TMR area was encrypted, flush it from the cache.
> -		 *
> -		 * If invoked during panic handling, local interrupts are
> -		 * disabled and all CPUs are stopped, so wbinvd_on_all_cpus()
> -		 * can't be used. In that case, wbinvd() is done on remote CPUs
> -		 * via the NMI callback, and done for this CPU later during
> -		 * SNP shutdown, so wbinvd_on_all_cpus() can be skipped.
> -		 */
> -		if (!panic)
> -			wbinvd_on_all_cpus();
> -
> -		__snp_free_firmware_pages(virt_to_page(sev_es_tmr),
> -					  get_order(sev_es_tmr_size),
> -					  true);
> -		sev_es_tmr = NULL;
> -	}
> -
> -	if (sev_init_ex_buffer) {
> -		__snp_free_firmware_pages(virt_to_page(sev_init_ex_buffer),
> -					  get_order(NV_LENGTH),
> -					  true);
> -		sev_init_ex_buffer = NULL;
> -	}
> +	__sev_release_firmware_buffers(panic);
>  
>  	__sev_snp_shutdown_locked(&error, panic);
>  }