linux-kernel - Re: [PATCH] KVM: x86: fix access code passed to gva_to

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Message-ID: <2f1dd99d-f19d-fec2-bbe1-53b8861bfe9e@redhat.com>
Date:   Mon, 17 Aug 2020 20:56:20 +0200
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     Sean Christopherson <sean.j.christopherson@...el.com>
Cc:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Subject: Re: [PATCH] KVM: x86: fix access code passed to gva_to_gpa

On 17/08/20 20:42, Sean Christopherson wrote:
> 
> Don't suppose you'd be in the mood to kill the bare 'unsigned'?
> 
>   WARNING: Prefer 'unsigned int' to bare use of 'unsigned'

u32 is even better.

> Alternatively, what about capturing the result in a new variable (instead of
> defining the mask) to make the wrap suck less (or just overflow like the
> current code), e.g.:
> 
>         u32 access = error_code &
>                      (PFERR_WRITE_MASK | PFERR_FETCH_MASK | PFERR_USER_MASK);
> 
>         if (!(error_code & PFERR_PRESENT_MASK) ||
>             vcpu->arch.walk_mmu->gva_to_gpa(vcpu, gva, access, &fault) != UNMAPPED_GVA) {

Sure, that's better.

Paolo