linux-kernel - Re: [PATCH v3 2/3] KVM: s390: vsie: Do the CRYCB validation first

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Message-Id: <e0822f44-f7cc-605c-a850-08f0d070c6d5@linux.ibm.com>
Date:   Thu, 23 Aug 2018 15:43:32 +0200
From:   Janosch Frank <frankja@...ux.ibm.com>
To:     Pierre Morel <pmorel@...ux.ibm.com>, david@...hat.com
Cc:     linux-kernel@...r.kernel.org, cohuck@...hat.com,
        linux-s390@...r.kernel.org, kvm@...r.kernel.org,
        akrowiak@...ux.ibm.com, borntraeger@...ibm.com,
        schwidefsky@...ibm.com, heiko.carstens@...ibm.com
Subject: Re: [PATCH v3 2/3] KVM: s390: vsie: Do the CRYCB validation first

On 8/23/18 12:25 PM, Pierre Morel wrote:
> When entering the SIE the CRYCB validation better
> be done independently of the instruction's
> availability.
> 
> Signed-off-by: Pierre Morel <pmorel@...ux.ibm.com>
> ---
>  arch/s390/kvm/vsie.c | 11 ++++++-----
>  1 file changed, 6 insertions(+), 5 deletions(-)
> 
> diff --git a/arch/s390/kvm/vsie.c b/arch/s390/kvm/vsie.c
> index 12b9707..38ea5da 100644
> --- a/arch/s390/kvm/vsie.c
> +++ b/arch/s390/kvm/vsie.c
> @@ -161,17 +161,18 @@ static int shadow_crycb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
>  	/* format-1 is supported with message-security-assist extension 3 */
>  	if (!test_kvm_facility(vcpu->kvm, 76))
>  		return 0;
> -	/* we may only allow it if enabled for guest 2 */
> -	ecb3_flags = scb_o->ecb3 & vcpu->arch.sie_block->ecb3 &
> -		     (ECB3_AES | ECB3_DEA);
> -	if (!ecb3_flags)
> -		return 0;
>  
>  	if ((crycb_addr & PAGE_MASK) != ((crycb_addr + 128) & PAGE_MASK))
>  		return set_validity_icpt(scb_s, 0x003CU);
>  	else if (!crycb_addr)
>  		return set_validity_icpt(scb_s, 0x0039U);
>  
> +	/* we may only allow it if enabled for guest 2 */
> +	ecb3_flags = scb_o->ecb3 & vcpu->arch.sie_block->ecb3 &
> +		     (ECB3_AES | ECB3_DEA);
> +	if (!ecb3_flags)
> +		return 0;
> +
>  	/* copy only the wrapping keys */
>  	if (read_guest_real(vcpu, crycb_addr + 72,
>  			    vsie_page->crycb.dea_wrapping_key_mask, 56))
> 

I seemed to have forgotten to add this while being preoccupied with the
search for the validity discussion in #3.

Reviewed-by: Janosch Frank <frankja@...ux.ibm.com>



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