[v4] Move initializing SEV/SNP functionality to KVM

[PATCH v4 3/7] crypto: ccp: Reset TMR size at SNP Shutdown

Posted by Ashish Kalra 10 months ago

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

When SEV-SNP is enabled the TMR needs to be 2MB aligned and 2MB sized,
ensure that TMR size is reset back to default when SNP is shutdown as
SNP initialization and shutdown as part of some SNP ioctls may leave
TMR size modified and cause subsequent SEV only initialization to fail.

Signed-off-by: Ashish Kalra <ashish.kalra@amd.com>
---
 drivers/crypto/ccp/sev-dev.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/crypto/ccp/sev-dev.c b/drivers/crypto/ccp/sev-dev.c
index b06f43eb18f7..be8a84ce24c7 100644
--- a/drivers/crypto/ccp/sev-dev.c
+++ b/drivers/crypto/ccp/sev-dev.c
@@ -1751,6 +1751,9 @@ static int __sev_snp_shutdown_locked(int *error, bool panic)
 	sev->snp_initialized = false;
 	dev_dbg(sev->dev, "SEV-SNP firmware shutdown\n");
 
+	/* Reset TMR size back to default */
+	sev_es_tmr_size = SEV_TMR_SIZE;
+
 	return ret;
 }
 
-- 
2.34.1

Re: [PATCH v4 3/7] crypto: ccp: Reset TMR size at SNP Shutdown

Posted by Tom Lendacky 10 months ago

On 2/19/25 14:53, Ashish Kalra wrote:
> From: Ashish Kalra <ashish.kalra@amd.com>
> 
> When SEV-SNP is enabled the TMR needs to be 2MB aligned and 2MB sized,
> ensure that TMR size is reset back to default when SNP is shutdown as
> SNP initialization and shutdown as part of some SNP ioctls may leave
> TMR size modified and cause subsequent SEV only initialization to fail.

This is a long run-on sentence, please re-work this to make it more
informative and clear as to what the issue is.

Other than that,

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

> 
> Signed-off-by: Ashish Kalra <ashish.kalra@amd.com>
> ---
>  drivers/crypto/ccp/sev-dev.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/crypto/ccp/sev-dev.c b/drivers/crypto/ccp/sev-dev.c
> index b06f43eb18f7..be8a84ce24c7 100644
> --- a/drivers/crypto/ccp/sev-dev.c
> +++ b/drivers/crypto/ccp/sev-dev.c
> @@ -1751,6 +1751,9 @@ static int __sev_snp_shutdown_locked(int *error, bool panic)
>  	sev->snp_initialized = false;
>  	dev_dbg(sev->dev, "SEV-SNP firmware shutdown\n");
>  
> +	/* Reset TMR size back to default */
> +	sev_es_tmr_size = SEV_TMR_SIZE;
> +
>  	return ret;
>  }
>

Re: [PATCH v4 3/7] crypto: ccp: Reset TMR size at SNP Shutdown

Posted by Dionna Amalie Glaze 10 months ago

On Wed, Feb 19, 2025 at 12:53 PM Ashish Kalra <Ashish.Kalra@amd.com> wrote:
>
> From: Ashish Kalra <ashish.kalra@amd.com>
>
> When SEV-SNP is enabled the TMR needs to be 2MB aligned and 2MB sized,
> ensure that TMR size is reset back to default when SNP is shutdown as
> SNP initialization and shutdown as part of some SNP ioctls may leave
> TMR size modified and cause subsequent SEV only initialization to fail.
>
> Signed-off-by: Ashish Kalra <ashish.kalra@amd.com>

Acked-by: Dionna Glaze <dionnaglaze@google.com>

> ---
>  drivers/crypto/ccp/sev-dev.c | 3 +++
>  1 file changed, 3 insertions(+)
>
> diff --git a/drivers/crypto/ccp/sev-dev.c b/drivers/crypto/ccp/sev-dev.c
> index b06f43eb18f7..be8a84ce24c7 100644
> --- a/drivers/crypto/ccp/sev-dev.c
> +++ b/drivers/crypto/ccp/sev-dev.c
> @@ -1751,6 +1751,9 @@ static int __sev_snp_shutdown_locked(int *error, bool panic)
>         sev->snp_initialized = false;
>         dev_dbg(sev->dev, "SEV-SNP firmware shutdown\n");
>
> +       /* Reset TMR size back to default */
> +       sev_es_tmr_size = SEV_TMR_SIZE;
> +
>         return ret;
>  }
>
> --
> 2.34.1
>


-- 
-Dionna Glaze, PhD, CISSP, CCSP (she/her)