Messages in this thread | | | Date | Thu, 18 Mar 2010 19:30:15 +0800 | From | Xiao Guangrong <> | Subject | Re: [PATCH v2] KVM MMU: check reserved bits only when CR4.PSE=1 or CR4.PAE=1 |
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Hi Marcelo,
Thanks for your review.
Marcelo Tosatti wrote: > On Wed, Mar 17, 2010 at 11:43:06AM +0800, Xiao Guangrong wrote: >> - The RSV bit is possibility set in error code when #PF occurred >> only if CR4.PSE=1 or CR4.PAE=1 >> >> - context->rsvd_bits_mask[1][0] is always 0 >> >> Changlog: >> Move this operation to reset_rsvds_bits_mask() address Avi Kivity's suggestion >> >> Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com> >> --- >> arch/x86/kvm/mmu.c | 12 +++++++++--- >> 1 files changed, 9 insertions(+), 3 deletions(-) >> >> diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c >> index b137515..c49f8ec 100644 >> --- a/arch/x86/kvm/mmu.c >> +++ b/arch/x86/kvm/mmu.c >> @@ -2288,18 +2288,26 @@ static void reset_rsvds_bits_mask(struct kvm_vcpu *vcpu, int level) >> >> if (!is_nx(vcpu)) >> exb_bit_rsvd = rsvd_bits(63, 63); >> + >> + context->rsvd_bits_mask[1][0] = 0; > > So if the guest enables PAT at PTE level you completly disable reserved > bit checking? You should only disable checking for [1][1] if !PSE.
Sorry, i make a mistake here because i see the current code is redundant: context->rsvd_bits_mask[1][0] = context->rsvd_bits_mask[1][0]; in every case.
This code is imported by commit fd2e987d, i think this is Avi Kivity's typo :-) i think the correct way is: ontext->rsvd_bits_mask[1][0] = context->rsvd_bits_mask[0][0];
I'll send a new version patch to fix it if you not object.
Xiao
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