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SubjectRe: [PATCH 2/7] KVM: MMU: cleanup for error mask set while walk guest page table
  On 09/27/2010 12:03 PM, Xiao Guangrong wrote:
> Small cleanup for set page fault error code
>
> Xiao Guangrong<xiaoguangrong@cn.fujitsu.com>
> ---
> arch/x86/kvm/paging_tmpl.h | 17 +++++++----------
> 1 files changed, 7 insertions(+), 10 deletions(-)
>
> diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
> index 2bdd843..a83ff37 100644
> --- a/arch/x86/kvm/paging_tmpl.h
> +++ b/arch/x86/kvm/paging_tmpl.h
> @@ -224,9 +224,7 @@ walk:
> is_cpuid_PSE36())
> gfn += pse36_gfn_delta(pte);
>
> - access |= write_fault ? PFERR_WRITE_MASK : 0;
> - access |= fetch_fault ? PFERR_FETCH_MASK : 0;
> - access |= user_fault ? PFERR_USER_MASK : 0;
> + access |= write_fault | fetch_fault | user_fault;
>
> real_gpa = mmu->translate_gpa(vcpu, gfn_to_gpa(gfn),
> access);
> @@ -268,10 +266,9 @@ error:
> walker->error_code = 0;
> if (present)
> walker->error_code |= PFERR_PRESENT_MASK;
> - if (write_fault)
> - walker->error_code |= PFERR_WRITE_MASK;
> - if (user_fault)
> - walker->error_code |= PFERR_USER_MASK;
> +
> + walker->error_code |= write_fault | user_fault;
> +
> if (fetch_fault&& mmu->nx)
> walker->error_code |= PFERR_FETCH_MASK;
> if (rsvd_fault)
> @@ -673,9 +670,9 @@ static gpa_t FNAME(gva_to_gpa)(struct kvm_vcpu *vcpu, gva_t vaddr, u32 access,
> int r;
>
> r = FNAME(walk_addr)(&walker, vcpu, vaddr,
> - !!(access& PFERR_WRITE_MASK),
> - !!(access& PFERR_USER_MASK),
> - !!(access& PFERR_FETCH_MASK));
> + access& PFERR_WRITE_MASK,
> + access& PFERR_USER_MASK,
> + access& PFERR_FETCH_MASK);
>
> if (r) {
> gpa = gfn_to_gpa(walker.gfn);

Interesting. Maybe a next step is to pass the page-fault error code
instead of the various bits? Not sure how that interacts with nested
ept (which has a different permission model).


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



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