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SubjectRe: [PATCH 3/4] KVM: MMU: notrap it if gpte's reserved is set
On 11/12/2010 12:34 PM, Xiao Guangrong wrote:
> We can past the page fault to guest directly if gpte's reserved
> is set
>

How can that work? shadow_notrap_nonpresent_pte causes a fault with
PFEC.P=PFEC.RSVD=0, while we need PFEC.P=PFEC.RSVD=1.

> Signed-off-by: Xiao Guangrong<xiaoguangrong@cn.fujitsu.com>
> ---
> arch/x86/kvm/paging_tmpl.h | 10 ++++++----
> 1 files changed, 6 insertions(+), 4 deletions(-)
>
> diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
> index 291342d..952357a 100644
> --- a/arch/x86/kvm/paging_tmpl.h
> +++ b/arch/x86/kvm/paging_tmpl.h
> @@ -760,6 +760,7 @@ static int FNAME(sync_page)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
> pt_element_t gpte;
> gpa_t pte_gpa;
> gfn_t gfn;
> + bool gpte_invalid;
>
> if (!is_shadow_present_pte(sp->spt[i]))
> continue;
> @@ -771,12 +772,13 @@ static int FNAME(sync_page)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
> return -EINVAL;
>
> gfn = gpte_to_gfn(gpte);
> - if (is_rsvd_bits_set(&vcpu->arch.mmu, gpte, PT_PAGE_TABLE_LEVEL)
> - || gfn != sp->gfns[i] || !is_present_gpte(gpte)
> - || !(gpte& PT_ACCESSED_MASK)) {
> + gpte_invalid = is_present_gpte(gpte) ||
> + is_rsvd_bits_set(&vcpu->arch.mmu, gpte, PT_PAGE_TABLE_LEVEL);

Shouldn't that be &&?

> + if (gpte_invalid || gfn != sp->gfns[i] ||
> + !(gpte& PT_ACCESSED_MASK)) {
> u64 nonpresent;
>
> - if (is_present_gpte(gpte) || !clear_unsync)
> + if (gpte_invalid || !clear_unsync)
> nonpresent = shadow_trap_nonpresent_pte;
> else
> nonpresent = shadow_notrap_nonpresent_pte;


--
error compiling committee.c: too many arguments to function



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