Re: [PATCH 1/10] KVM MMU: fix for calculating gpa in invlpg code

Avi Kivity
2010-04-23T11:23:56Z

On 04/22/2010 09:12 AM, Xiao Guangrong wrote:
> If the guest is 32-bit, we should use 'quadrant' to adjust gpa
> offset
>
>

Good catch. Only affects kvm_mmu_pte_write(), so I don't think this had
ill effects other than not prefetching the correct address?

> @@ -478,9 +478,14 @@ static void FNAME(invlpg)(struct kvm_vcpu *vcpu, gva_t gva)
> ((level == PT_DIRECTORY_LEVEL&& is_large_pte(*sptep))) ||
> ((level == PT_PDPE_LEVEL&& is_large_pte(*sptep)))) {
> struct kvm_mmu_page *sp = page_header(__pa(sptep));
> + int offset = 0;
> +
> + if (PTTYPE == 32)
> + offset = sp->role.quadrant<< PT64_LEVEL_BITS;;
>

Wrong for PT_DIRECTORY_LEVEL (should be q << 8). Also, too many
semicolons.

--
Do not meddle in the internals of kernels, for they are subtle and quick to panic.