On Wed, Nov 17, 2010 at 12:10:08PM +0800, Xiao Guangrong wrote:
> Some paths forgot to flush vcpu tlbs after remove rmap, this
> patch fix it.
>
> Signed-off-by: Xiao Guangrong <xiaoguangrong@xxxxxxxxxxxxxx>
> ---
> arch/x86/kvm/mmu.c | 14 +++++++++++---
> arch/x86/kvm/paging_tmpl.h | 1 +
> 2 files changed, 12 insertions(+), 3 deletions(-)
>
> diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
> index bdb9fa9..e008ae7 100644
> --- a/arch/x86/kvm/mmu.c
> +++ b/arch/x86/kvm/mmu.c
> @@ -736,10 +736,16 @@ static int set_spte_track_bits(u64 *sptep, u64 new_spte)
> return 1;
> }
>
> -static void drop_spte(struct kvm *kvm, u64 *sptep, u64 new_spte)
> +static bool drop_spte(struct kvm *kvm, u64 *sptep, u64 new_spte)
> {
> - if (set_spte_track_bits(sptep, new_spte))
> + bool ret = false;
> +
> + if (set_spte_track_bits(sptep, new_spte)) {
> rmap_remove(kvm, sptep);
> + ret = true;
> + }
> +
> + return ret;
> }
>
> static u64 *rmap_next(struct kvm *kvm, unsigned long *rmapp, u64 *spte)
> @@ -1997,7 +2003,9 @@ static int set_spte(struct kvm_vcpu *vcpu, u64 *sptep,
> if (level > PT_PAGE_TABLE_LEVEL &&
> has_wrprotected_page(vcpu->kvm, gfn, level)) {
> ret = 1;
> - drop_spte(vcpu->kvm, sptep, shadow_trap_nonpresent_pte);
> + if (drop_spte(vcpu->kvm, sptep,
> + shadow_trap_nonpresent_pte))
> + kvm_flush_remote_tlbs(vcpu->kvm);
> goto done;
The spte should not be present before (this condition can happen if the
has_wrprotected_page check from mapping_level races, which is possible
since it runs without mmu_lock protection).
> diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
> index ba00eef..58b4d9a 100644
> --- a/arch/x86/kvm/paging_tmpl.h
> +++ b/arch/x86/kvm/paging_tmpl.h
> @@ -781,6 +781,7 @@ static int FNAME(sync_page)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
> else
> nonpresent = shadow_notrap_nonpresent_pte;
> drop_spte(vcpu->kvm, &sp->spt[i], nonpresent);
> + kvm_flush_remote_tlbs(vcpu->kvm);
> continue;
> }
This is not needed. Guest is responsible for flushing on
present->nonpresent change.
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