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Message-ID: <20100315094109.GB13108@8bytes.org>
Date: Mon, 15 Mar 2010 10:41:09 +0100
From: Joerg Roedel <joro@...tes.org>
To: Avi Kivity <avi@...hat.com>
Cc: Joerg Roedel <joerg.roedel@....com>,
Marcelo Tosatti <mtosatti@...hat.com>,
Alexander Graf <agraf@...e.de>, kvm@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH 15/18] KVM: MMU: Propagate the right fault back to the
guest after gva_to_gpa
On Mon, Mar 15, 2010 at 11:23:07AM +0200, Avi Kivity wrote:
> On 03/15/2010 11:06 AM, Joerg Roedel wrote:
>> On Mon, Mar 15, 2010 at 09:36:52AM +0200, Avi Kivity wrote:
>>
>>> On 03/03/2010 09:12 PM, Joerg Roedel wrote:
>>>
>>>> This patch implements logic to make sure that either a
>>>> page-fault/page-fault-vmexit or a nested-page-fault-vmexit
>>>> is propagated back to the guest.
>>>>
>>>> Signed-off-by: Joerg Roedel<joerg.roedel@....com>
>>>> ---
>>>> arch/x86/kvm/mmu.h | 1 +
>>>> arch/x86/kvm/paging_tmpl.h | 2 ++
>>>> arch/x86/kvm/x86.c | 15 ++++++++++++++-
>>>> 3 files changed, 17 insertions(+), 1 deletions(-)
>>>>
>>>> diff --git a/arch/x86/kvm/mmu.h b/arch/x86/kvm/mmu.h
>>>> index 64f619b..b42b27e 100644
>>>> --- a/arch/x86/kvm/mmu.h
>>>> +++ b/arch/x86/kvm/mmu.h
>>>> @@ -47,6 +47,7 @@
>>>> #define PFERR_USER_MASK (1U<< 2)
>>>> #define PFERR_RSVD_MASK (1U<< 3)
>>>> #define PFERR_FETCH_MASK (1U<< 4)
>>>> +#define PFERR_NESTED_MASK (1U<< 31)
>>>>
>>>>
>>>
>>> Why is this needed? Queue an ordinary page fault page; the injection
>>> code should check the page fault intercept and #VMEXIT if needed.
>>>
>> This is needed because we could have a nested page fault or an ordinary
>> page fault which need to be propagated.
>>
>
> Right.
>
> Why is pio_copy_data() changed? One would think that it would be an
> all-or-nothing affair.
It was the only place I found where the PROPAGATE_FAULT value was
checked and actually propagated.
Joerg
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