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

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Message-ID: <89815665-4ff8-9eac-8b75-78c50f866a6e@amd.com>
Date: Tue, 10 Dec 2024 15:52:35 -0600
From: Tom Lendacky <thomas.lendacky@....com>
To: Ashish Kalra <Ashish.Kalra@....com>, 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,
 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: Re: [PATCH 3/7] crypto: ccp: Reset TMR size at SNP Shutdown

On 12/9/24 17:25, Ashish Kalra wrote:
> From: Ashish Kalra <ashish.kalra@....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.

I think a bit more info here about why this is (now) needed would be good.

Thanks,
Tom

> 
> Signed-off-by: Ashish Kalra <ashish.kalra@....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 d8673d8836f1..bc121ad9ec26 100644
> --- a/drivers/crypto/ccp/sev-dev.c
> +++ b/drivers/crypto/ccp/sev-dev.c
> @@ -1750,6 +1750,9 @@ 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;
>  }
>