On Wed, Nov 17, 2010 at 12:10:50PM +0800, Xiao Guangrong wrote:
> We just need flush tlb if overwrite a writable spte with a read-only
> one.
>
> And we should move this operation to set_spte() for sync_page path
>
> Signed-off-by: Xiao Guangrong <xiaoguangrong@xxxxxxxxxxxxxx>
> ---
> arch/x86/kvm/mmu.c | 20 +++++++++-----------
> 1 files changed, 9 insertions(+), 11 deletions(-)
>
> diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
> index e008ae7..9bad960 100644
> --- a/arch/x86/kvm/mmu.c
> +++ b/arch/x86/kvm/mmu.c
> @@ -1966,7 +1966,7 @@ static int set_spte(struct kvm_vcpu *vcpu, u64 *sptep,
> gfn_t gfn, pfn_t pfn, bool speculative,
> bool can_unsync, bool reset_host_protection)
> {
> - u64 spte;
> + u64 spte, entry = *sptep;
> int ret = 0;
>
> /*
> @@ -2039,6 +2039,14 @@ static int set_spte(struct kvm_vcpu *vcpu, u64 *sptep,
>
> set_pte:
> update_spte(sptep, spte);
> + /*
> + * If we overwrite a writable spte with a read-only one we
> + * should flush remote TLBs. Otherwise rmap_write_protect
> + * will find a read-only spte, even though the writable spte
> + * might be cached on a CPU's TLB.
> + */
> + if (is_writable_pte(entry) && !is_writable_pte(*sptep))
> + kvm_flush_remote_tlbs(vcpu->kvm);
There is no need to flush on sync_page path since the guest is
responsible for it.
--
To unsubscribe from this list: send the line "unsubscribe kvm" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
