On 25/03/2016 14:19, Xiao Guangrong wrote:
> The obsolete sp should not be used on current vCPUs and should not hurt
> vCPU's running, so skip it from for_each_gfn_sp() and
> for_each_gfn_indirect_valid_sp()
>
> The side effort is we will double check role.invalid in kvm_mmu_get_page()
> but i think it is okay as role is well cached
>
> Signed-off-by: Xiao Guangrong <guangrong.xiao@xxxxxxxxxxxxxxx>
Queued for 4.7.
Paolo
> ---
> arch/x86/kvm/mmu.c | 28 ++++++++++++----------------
> 1 file changed, 12 insertions(+), 16 deletions(-)
>
> diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
> index c396e8b..4d66a9e 100644
> --- a/arch/x86/kvm/mmu.c
> +++ b/arch/x86/kvm/mmu.c
> @@ -1906,18 +1906,17 @@ static void kvm_mmu_commit_zap_page(struct kvm *kvm,
> * since it has been deleted from active_mmu_pages but still can be found
> * at hast list.
> *
> - * for_each_gfn_indirect_valid_sp has skipped that kind of page and
> - * kvm_mmu_get_page(), the only user of for_each_gfn_sp(), has skipped
> - * all the obsolete pages.
> + * for_each_gfn_valid_sp() has skipped that kind of pages.
> */
> -#define for_each_gfn_sp(_kvm, _sp, _gfn) \
> +#define for_each_gfn_valid_sp(_kvm, _sp, _gfn) \
> hlist_for_each_entry(_sp, \
> &(_kvm)->arch.mmu_page_hash[kvm_page_table_hashfn(_gfn)], hash_link) \
> - if ((_sp)->gfn != (_gfn)) {} else
> + if ((_sp)->gfn != (_gfn) || is_obsolete_sp((_kvm), (_sp)) \
> + || (_sp)->role.invalid) {} else
>
> #define for_each_gfn_indirect_valid_sp(_kvm, _sp, _gfn) \
> - for_each_gfn_sp(_kvm, _sp, _gfn) \
> - if ((_sp)->role.direct || (_sp)->role.invalid) {} else
> + for_each_gfn_valid_sp(_kvm, _sp, _gfn) \
> + if ((_sp)->role.direct) {} else
>
> /* @sp->gfn should be write-protected at the call site */
> static bool __kvm_sync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
> @@ -1958,6 +1957,11 @@ static void kvm_mmu_audit(struct kvm_vcpu *vcpu, int point) { }
> static void mmu_audit_disable(void) { }
> #endif
>
> +static bool is_obsolete_sp(struct kvm *kvm, struct kvm_mmu_page *sp)
> +{
> + return unlikely(sp->mmu_valid_gen != kvm->arch.mmu_valid_gen);
> +}
> +
> static bool kvm_sync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
> struct list_head *invalid_list)
> {
> @@ -2092,11 +2096,6 @@ static void clear_sp_write_flooding_count(u64 *spte)
> __clear_sp_write_flooding_count(sp);
> }
>
> -static bool is_obsolete_sp(struct kvm *kvm, struct kvm_mmu_page *sp)
> -{
> - return unlikely(sp->mmu_valid_gen != kvm->arch.mmu_valid_gen);
> -}
> -
> static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu,
> gfn_t gfn,
> gva_t gaddr,
> @@ -2123,10 +2122,7 @@ static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu,
> quadrant &= (1 << ((PT32_PT_BITS - PT64_PT_BITS) * level)) - 1;
> role.quadrant = quadrant;
> }
> - for_each_gfn_sp(vcpu->kvm, sp, gfn) {
> - if (is_obsolete_sp(vcpu->kvm, sp))
> - continue;
> -
> + for_each_gfn_valid_sp(vcpu->kvm, sp, gfn) {
> if (!need_sync && sp->unsync)
> need_sync = true;
>
>
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