linux-kernel - Re: [PATCH 9/9] KVM: VMX: pass correct DR6 for GD userspace exit

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Message-ID: <20200506175013.GP6299@xz-x1>
Date:   Wed, 6 May 2020 13:50:13 -0400
From:   Peter Xu <peterx@...hat.com>
To:     Paolo Bonzini <pbonzini@...hat.com>
Cc:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
        Sean Christopherson <sean.j.christopherson@...el.com>
Subject: Re: [PATCH 9/9] KVM: VMX: pass correct DR6 for GD userspace exit

On Wed, May 06, 2020 at 07:10:34AM -0400, Paolo Bonzini wrote:
> When KVM_EXIT_DEBUG is raised for the disabled-breakpoints case (DR7.GD),
> DR6 was incorrectly copied from the value in the VM.  Instead,
> DR6.BD should be set in order to catch this case.
> 
> On AMD this does not need any special code because the processor triggers
> a #DB exception that is intercepted.  However, the testcase would fail
> without the previous patch because both DR6.BS and DR6.BD would be set.
> 
> Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>

Reviewed-by: Peter Xu <peterx@...hat.com>

-- 
Peter Xu