From mboxrd@z Thu Jan  1 00:00:00 1970
From: George Dunlap <george.dunlap@eu.citrix.com>
Subject: Re: [PATCH RFC v12 08/21] pvh: vmx-specific changes
Date: Mon, 16 Sep 2013 10:15:55 +0100
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To: Jan Beulich <JBeulich@suse.com>
Cc: Tim Deegan <tim@xen.org>, Keir Fraser <keir@xen.org>, Jan Beulich <jan.beulich@suse.com>, xen-devel@lists.xen.org
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On 16/09/13 08:37, Jan Beulich wrote:
>>>> On 13.09.13 at 18:38, George Dunlap <george.dunlap@eu.citrix.com> wrote:
>> On 13/09/13 17:25, George Dunlap wrote:
>>> +    /* PVH: Why is ET not set? */
>>> +    v->arch.hvm_vcpu.guest_cr[0] = is_pvh_domain(d) ?
>>> +        ( X86_CR0_PG | X86_CR0_NE | X86_CR0_PE | X86_CR0_WP )
>>> +        : ( X86_CR0_PE | X86_CR0_ET );
>> I also couldn't figure out why CR0_ET wasn't set for PVH vms; is it not
>> set for PV vms?
> This one's certainly wrong - it shouldn't even be possible to clear
> CR0.ET in hardware on anything post-486 (i.e. trying to clear it
> would be silently ignored by the hardware, and not setting it in
> the code above is merely confusing, but not actively breaking
> anything).

Right -- so it would be better if this were something like:

v->arch.hvm_vcpu.guest_cr[0] = $SHARED_FLAGS;
if ( is_pvh_domain(d))
     v->arch.hvm_vcpu.guest_cr[0] |= $PVH_FLAGS.

  -George