Re: [PATCH v2 6/6] KVM: x86/mmu: Use 1 as the size of gfn range for tlb flushing in FNAME(invlpg)()

David Matlack
2022-09-07T17:40:29Z

On Wed, Aug 24, 2022 at 05:29:23PM +0800, Hou Wenlong wrote:
> Only SP with PG_LEVLE_4K level could be unsync, so the size of gfn range
> must be 1.
>
> Signed-off-by: Hou Wenlong <houwenlong.hwl@antgroup.com>
> ---
> arch/x86/kvm/mmu/paging_tmpl.h | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/arch/x86/kvm/mmu/paging_tmpl.h b/arch/x86/kvm/mmu/paging_tmpl.h
> index 04149c704d5b..486a3163b1e4 100644
> --- a/arch/x86/kvm/mmu/paging_tmpl.h
> +++ b/arch/x86/kvm/mmu/paging_tmpl.h
> @@ -937,7 +937,8 @@ static void FNAME(invlpg)(struct kvm_vcpu *vcpu, gva_t gva, hpa_t root_hpa)
>
> mmu_page_zap_pte(vcpu->kvm, sp, sptep, NULL);
> if (is_shadow_present_pte(old_spte))
> - kvm_flush_remote_tlbs_sptep(vcpu->kvm, sptep);
> + kvm_flush_remote_tlbs_gfn(vcpu->kvm,
> + kvm_mmu_page_get_gfn(sp, sptep - sp->spt), 1);

The third argument to kvm_flush_remote_tlbs_gfn() is the level, not the
number of pages. But that aside, I don't understand why this patch is
necessary. kvm_flush_remote_tlbs_sptep() should already do the right
thing.

>
> if (!rmap_can_add(vcpu))
> break;
> --
> 2.31.1
>