From: Vitaly Kuznetsov <vkuznets@redhat.com>
To: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 04/10] KVM: VMX: Do Hyper-V TLB flush iff vCPU's EPTP hasn't been flushed
Date: Wed, 21 Oct 2020 14:23:13 +0200 [thread overview]
Message-ID: <87zh4f4vke.fsf@vitty.brq.redhat.com> (raw)
In-Reply-To: <20201020215613.8972-5-sean.j.christopherson@intel.com>
Sean Christopherson <sean.j.christopherson@intel.com> writes:
> Combine the for-loops for Hyper-V TLB EPTP checking and flushing, and in
> doing so skip flushes for vCPUs whose EPTP matches the target EPTP.
>
> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
> ---
> arch/x86/kvm/vmx/vmx.c | 20 ++++++--------------
> 1 file changed, 6 insertions(+), 14 deletions(-)
>
> diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
> index bba6d91f1fe1..52cb9eec1db3 100644
> --- a/arch/x86/kvm/vmx/vmx.c
> +++ b/arch/x86/kvm/vmx/vmx.c
> @@ -502,31 +502,23 @@ static int hv_remote_flush_tlb_with_range(struct kvm *kvm,
>
> spin_lock(&kvm_vmx->ept_pointer_lock);
>
> - if (kvm_vmx->ept_pointers_match == EPT_POINTERS_CHECK) {
> + if (kvm_vmx->ept_pointers_match != EPT_POINTERS_MATCH) {
> kvm_vmx->ept_pointers_match = EPT_POINTERS_MATCH;
> kvm_vmx->hv_tlb_eptp = INVALID_PAGE;
>
> kvm_for_each_vcpu(i, vcpu, kvm) {
> tmp_eptp = to_vmx(vcpu)->ept_pointer;
> - if (!VALID_PAGE(tmp_eptp))
> + if (!VALID_PAGE(tmp_eptp) ||
> + tmp_eptp == kvm_vmx->hv_tlb_eptp)
> continue;
>
> - if (!VALID_PAGE(kvm_vmx->hv_tlb_eptp)) {
> + if (!VALID_PAGE(kvm_vmx->hv_tlb_eptp))
> kvm_vmx->hv_tlb_eptp = tmp_eptp;
> - } else if (kvm_vmx->hv_tlb_eptp != tmp_eptp) {
> + else
> kvm_vmx->ept_pointers_match
> = EPT_POINTERS_MISMATCH;
> - break;
> - }
> - }
> - }
>
> - if (kvm_vmx->ept_pointers_match != EPT_POINTERS_MATCH) {
> - kvm_for_each_vcpu(i, vcpu, kvm) {
> - /* If ept_pointer is invalid pointer, bypass flush request. */
> - if (VALID_PAGE(to_vmx(vcpu)->ept_pointer))
> - ret |= hv_remote_flush_eptp(to_vmx(vcpu)->ept_pointer,
> - range);
> + ret |= hv_remote_flush_eptp(tmp_eptp, range);
> }
> } else if (VALID_PAGE(kvm_vmx->hv_tlb_eptp)) {
> ret = hv_remote_flush_eptp(kvm_vmx->hv_tlb_eptp, range);
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
I have an unrelated question though. Does it make sense to call
hv_remote_flush_eptp() in case all EPTPs matches with ept_pointer_lock
spinlock held? Like if we had a match by the time of the call, does it
make a difference if the situation will change before or right after we
do the hypercall?
--
Vitaly
next prev parent reply other threads:[~2020-10-21 12:23 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-20 21:56 [PATCH v2 00/10] KVM: VMX: Clean up Hyper-V PV TLB flush Sean Christopherson
2020-10-20 21:56 ` [PATCH v2 01/10] KVM: VMX: Track common EPTP for Hyper-V's paravirt " Sean Christopherson
2020-10-21 11:57 ` Vitaly Kuznetsov
2020-10-20 21:56 ` [PATCH v2 02/10] KVM: VMX: Stash kvm_vmx in a local variable for Hyper-V " Sean Christopherson
2020-10-21 12:00 ` Vitaly Kuznetsov
2020-10-20 21:56 ` [PATCH v2 03/10] KVM: VMX: Fold Hyper-V EPTP checking into it's only caller Sean Christopherson
2020-10-21 12:08 ` Vitaly Kuznetsov
2020-10-20 21:56 ` [PATCH v2 04/10] KVM: VMX: Do Hyper-V TLB flush iff vCPU's EPTP hasn't been flushed Sean Christopherson
2020-10-21 12:23 ` Vitaly Kuznetsov [this message]
2020-10-20 21:56 ` [PATCH v2 05/10] KVM: VMX: Invalidate hv_tlb_eptp to denote an EPTP mismatch Sean Christopherson
2020-10-21 12:39 ` Vitaly Kuznetsov
2020-10-21 16:38 ` Sean Christopherson
2020-10-22 9:03 ` Vitaly Kuznetsov
2020-10-20 21:56 ` [PATCH v2 06/10] KVM: VMX: Don't invalidate hv_tlb_eptp if the new EPTP matches Sean Christopherson
2020-10-21 13:47 ` Vitaly Kuznetsov
2020-10-20 21:56 ` [PATCH v2 07/10] KVM: VMX: Explicitly check for hv_remote_flush_tlb when loading pgd Sean Christopherson
[not found] ` <87r1pr4q8z.fsf@vitty.brq.redhat.com>
2020-10-21 17:30 ` Sean Christopherson
2020-10-20 21:56 ` [PATCH v2 08/10] KVM: VMX: Define Hyper-V paravirt TLB flush fields iff Hyper-V is enabled Sean Christopherson
2020-10-21 14:20 ` Vitaly Kuznetsov
2020-10-20 21:56 ` [PATCH v2 09/10] KVM: VMX: Skip additional Hyper-V TLB EPTP flushes if one fails Sean Christopherson
2020-10-21 14:22 ` Vitaly Kuznetsov
2020-10-20 21:56 ` [PATCH v2 10/10] KVM: VMX: Track PGD instead of EPTP for paravirt Hyper-V TLB flush Sean Christopherson
[not found] ` <87imb34p9b.fsf@vitty.brq.redhat.com>
2020-10-21 17:59 ` Sean Christopherson
2020-10-21 9:18 ` [PATCH v2 00/10] KVM: VMX: Clean up Hyper-V PV " Vitaly Kuznetsov
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