From: Sean Christopherson <sean.j.christopherson@intel.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>,
Vitaly Kuznetsov <vkuznets@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: [PATCH v3 06/11] KVM: VMX: Invalidate hv_tlb_eptp to denote an EPTP mismatch
Date: Tue, 27 Oct 2020 14:23:41 -0700 [thread overview]
Message-ID: <20201027212346.23409-7-sean.j.christopherson@intel.com> (raw)
In-Reply-To: <20201027212346.23409-1-sean.j.christopherson@intel.com>
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.christopherson@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;
};
--
2.28.0
next prev parent reply other threads:[~2020-10-27 21:24 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-27 21:23 [PATCH v3 00/11] KVM: VMX: Clean up Hyper-V PV TLB flush Sean Christopherson
2020-10-27 21:23 ` [PATCH v3 01/11] KVM: x86: Get active PCID only when writing a CR3 value Sean Christopherson
2020-11-12 10:11 ` Vitaly Kuznetsov
2021-01-27 17:30 ` Paolo Bonzini
2020-10-27 21:23 ` [PATCH v3 02/11] KVM: VMX: Track common EPTP for Hyper-V's paravirt TLB flush Sean Christopherson
2020-11-12 10:27 ` Vitaly Kuznetsov
2020-10-27 21:23 ` [PATCH v3 03/11] KVM: VMX: Stash kvm_vmx in a local variable for Hyper-V " Sean Christopherson
2020-10-27 21:23 ` [PATCH v3 04/11] KVM: VMX: Fold Hyper-V EPTP checking into it's only caller Sean Christopherson
2020-11-12 10:41 ` Vitaly Kuznetsov
2020-10-27 21:23 ` [PATCH v3 05/11] KVM: VMX: Do Hyper-V TLB flush iff vCPU's EPTP hasn't been flushed Sean Christopherson
2020-11-12 10:47 ` Vitaly Kuznetsov
2020-10-27 21:23 ` Sean Christopherson [this message]
2020-11-12 10:50 ` [PATCH v3 06/11] KVM: VMX: Invalidate hv_tlb_eptp to denote an EPTP mismatch Vitaly Kuznetsov
2020-10-27 21:23 ` [PATCH v3 07/11] KVM: VMX: Don't invalidate hv_tlb_eptp if the new EPTP matches Sean Christopherson
2020-10-27 21:23 ` [PATCH v3 08/11] KVM: VMX: Explicitly check for hv_remote_flush_tlb when loading pgd Sean Christopherson
2020-10-27 21:23 ` [PATCH v3 09/11] KVM: VMX: Define Hyper-V paravirt TLB flush fields iff Hyper-V is enabled Sean Christopherson
2020-11-12 10:52 ` Vitaly Kuznetsov
2020-10-27 21:23 ` [PATCH v3 10/11] KVM: VMX: Skip additional Hyper-V TLB EPTP flushes if one fails Sean Christopherson
2020-11-12 10:59 ` Vitaly Kuznetsov
2020-10-27 21:23 ` [PATCH v3 11/11] KVM: VMX: Track root HPA instead of EPTP for paravirt Hyper-V TLB flush Sean Christopherson
2020-11-12 11:02 ` Vitaly Kuznetsov
2021-01-27 18:10 ` [PATCH v3 00/11] KVM: VMX: Clean up Hyper-V PV " Paolo Bonzini
2021-03-02 18:56 ` Sean Christopherson
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