Sean Christopherson <sean.j.christopher...@intel.com> writes:
> Drop the dedicated 'ept_pointers_match' field in favor of stuffing
> 'hv_tlb_eptp' with INVALID_PAGE to mark it as invalid, i.e. to denote
> that there is at least one EPTP mismatch. Use a local variable to
> track whether or not a mismatch is detected so that hv_tlb_eptp can be
> used to skip redundant flushes.
>
> No functional change intended.
>
> Signed-off-by: Sean Christopherson <sean.j.christopher...@intel.com>
> ---
> arch/x86/kvm/vmx/vmx.c | 35 +++++++++++++++++++++++------------
> arch/x86/kvm/vmx/vmx.h | 7 -------
> 2 files changed, 23 insertions(+), 19 deletions(-)
>
> diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
> index 17b228c4ba19..25a714cda662 100644
> --- a/arch/x86/kvm/vmx/vmx.c
> +++ b/arch/x86/kvm/vmx/vmx.c
> @@ -500,32 +500,44 @@ static int hv_remote_flush_tlb_with_range(struct kvm
> *kvm,
> {
> struct kvm_vmx *kvm_vmx = to_kvm_vmx(kvm);
> struct kvm_vcpu *vcpu;
> - int ret = 0, i;
> + int ret = 0, i, nr_unique_valid_eptps;
> u64 tmp_eptp;
>
> spin_lock(&kvm_vmx->ept_pointer_lock);
>
> - if (kvm_vmx->ept_pointers_match != EPT_POINTERS_MATCH) {
> - kvm_vmx->ept_pointers_match = EPT_POINTERS_MATCH;
> - kvm_vmx->hv_tlb_eptp = INVALID_PAGE;
> + if (!VALID_PAGE(kvm_vmx->hv_tlb_eptp)) {
> + nr_unique_valid_eptps = 0;
>
> + /*
> + * Flush all valid EPTPs, and see if all vCPUs have converged
> + * on a common EPTP, in which case future flushes can skip the
> + * loop and flush the common EPTP.
> + */
> kvm_for_each_vcpu(i, vcpu, kvm) {
> tmp_eptp = to_vmx(vcpu)->ept_pointer;
> if (!VALID_PAGE(tmp_eptp) ||
> tmp_eptp == kvm_vmx->hv_tlb_eptp)
> continue;
>
> - if (!VALID_PAGE(kvm_vmx->hv_tlb_eptp))
> + /*
> + * Set the tracked EPTP to the first valid EPTP. Keep
> + * this EPTP for the entirety of the loop even if more
> + * EPTPs are encountered as a low effort optimization
> + * to avoid flushing the same (first) EPTP again.
> + */
> + if (++nr_unique_valid_eptps == 1)
> kvm_vmx->hv_tlb_eptp = tmp_eptp;
> - else
> - kvm_vmx->ept_pointers_match
> - = EPT_POINTERS_MISMATCH;
>
> ret |= hv_remote_flush_eptp(tmp_eptp, range);
> }
> - if (kvm_vmx->ept_pointers_match == EPT_POINTERS_MISMATCH)
> +
> + /*
> + * The optimized flush of a single EPTP can't be used if there
> + * are multiple valid EPTPs (obviously).
> + */
> + if (nr_unique_valid_eptps > 1)
> kvm_vmx->hv_tlb_eptp = INVALID_PAGE;
> - } else if (VALID_PAGE(kvm_vmx->hv_tlb_eptp)) {
> + } else {
> ret = hv_remote_flush_eptp(kvm_vmx->hv_tlb_eptp, range);
> }
>
> @@ -3060,8 +3072,7 @@ static void vmx_load_mmu_pgd(struct kvm_vcpu *vcpu,
> hpa_t root_hpa,
> if (kvm_x86_ops.tlb_remote_flush) {
> spin_lock(&to_kvm_vmx(kvm)->ept_pointer_lock);
> to_vmx(vcpu)->ept_pointer = eptp;
> - to_kvm_vmx(kvm)->ept_pointers_match
> - = EPT_POINTERS_CHECK;
> + to_kvm_vmx(kvm)->hv_tlb_eptp = INVALID_PAGE;
> spin_unlock(&to_kvm_vmx(kvm)->ept_pointer_lock);
> }
>
> diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h
> index 9a25e83f8b96..cecc2a641e19 100644
> --- a/arch/x86/kvm/vmx/vmx.h
> +++ b/arch/x86/kvm/vmx/vmx.h
> @@ -288,12 +288,6 @@ struct vcpu_vmx {
> } shadow_msr_intercept;
> };
>
> -enum ept_pointers_status {
> - EPT_POINTERS_CHECK = 0,
> - EPT_POINTERS_MATCH = 1,
> - EPT_POINTERS_MISMATCH = 2
> -};
> -
> struct kvm_vmx {
> struct kvm kvm;
>
> @@ -302,7 +296,6 @@ struct kvm_vmx {
> gpa_t ept_identity_map_addr;
>
> hpa_t hv_tlb_eptp;
> - enum ept_pointers_status ept_pointers_match;
> spinlock_t ept_pointer_lock;
> };
This looks really neat and straighforward now, thanks!
Reviewed-by: Vitaly Kuznetsov <vkuzn...@redhat.com>
--
Vitaly
