linux-kernel - Re: [PATCH 12/12] KVM: guest_memfd: let kvm_gmem

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Message-ID: <20240717224945.pg2hegox6si4cqrm@amd.com>
Date: Wed, 17 Jul 2024 17:49:45 -0500
From: Michael Roth <michael.roth@....com>
To: Paolo Bonzini <pbonzini@...hat.com>
CC: <linux-kernel@...r.kernel.org>, <kvm@...r.kernel.org>, <seanjc@...gle.com>
Subject: Re: [PATCH 12/12] KVM: guest_memfd: let kvm_gmem_populate() operate
 only on private gfns

On Thu, Jul 11, 2024 at 06:27:55PM -0400, Paolo Bonzini wrote:
> This check is currently performed by sev_gmem_post_populate(), but it
> applies to all callers of kvm_gmem_populate(): the point of the function
> is that the memory is being encrypted and some work has to be done
> on all the gfns in order to encrypt them.
> 
> Therefore, check the KVM_MEMORY_ATTRIBUTE_PRIVATE attribute prior
> to invoking the callback, and stop the operation if a shared page
> is encountered.  Because CONFIG_KVM_PRIVATE_MEM in principle does
> not require attributes, this makes kvm_gmem_populate() depend on
> CONFIG_KVM_GENERIC_PRIVATE_MEM (which does require them).
> 
> Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>

Reviewed-by: Michael Roth <michael.roth@....com>