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 02/11] KVM: VMX: Track common EPTP for Hyper-V's paravirt TLB flush
Date: Tue, 27 Oct 2020 14:23:37 -0700 [thread overview]
Message-ID: <20201027212346.23409-3-sean.j.christopherson@intel.com> (raw)
In-Reply-To: <20201027212346.23409-1-sean.j.christopherson@intel.com>
Explicitly track the EPTP that is common to all vCPUs instead of
grabbing vCPU0's EPTP when invoking Hyper-V's paravirt TLB flush.
Tracking the EPTP will allow optimizing the checks when loading a new
EPTP and will also allow dropping ept_pointer_match, e.g. by marking
the common EPTP as invalid.
This also technically fixes a bug where KVM could theoretically flush an
invalid GPA if all vCPUs have an invalid root. In practice, it's likely
impossible to trigger a remote TLB flush in such a scenario. In any
case, the superfluous flush is completely benign.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
arch/x86/kvm/vmx/vmx.c | 20 +++++++++-----------
arch/x86/kvm/vmx/vmx.h | 1 +
2 files changed, 10 insertions(+), 11 deletions(-)
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 273a3206cef7..ebc87df4da4d 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -483,12 +483,14 @@ static void check_ept_pointer_match(struct kvm *kvm)
if (!VALID_PAGE(tmp_eptp)) {
tmp_eptp = to_vmx(vcpu)->ept_pointer;
} else if (tmp_eptp != to_vmx(vcpu)->ept_pointer) {
+ to_kvm_vmx(kvm)->hv_tlb_eptp = INVALID_PAGE;
to_kvm_vmx(kvm)->ept_pointers_match
= EPT_POINTERS_MISMATCH;
return;
}
}
+ to_kvm_vmx(kvm)->hv_tlb_eptp = tmp_eptp;
to_kvm_vmx(kvm)->ept_pointers_match = EPT_POINTERS_MATCH;
}
@@ -501,21 +503,18 @@ static int kvm_fill_hv_flush_list_func(struct hv_guest_mapping_flush_list *flush
range->pages);
}
-static inline int __hv_remote_flush_tlb_with_range(struct kvm *kvm,
- struct kvm_vcpu *vcpu, struct kvm_tlb_range *range)
+static inline int hv_remote_flush_eptp(u64 eptp, struct kvm_tlb_range *range)
{
- u64 ept_pointer = to_vmx(vcpu)->ept_pointer;
-
/*
* FLUSH_GUEST_PHYSICAL_ADDRESS_SPACE hypercall needs address
* of the base of EPT PML4 table, strip off EPT configuration
* information.
*/
if (range)
- return hyperv_flush_guest_mapping_range(ept_pointer & PAGE_MASK,
+ return hyperv_flush_guest_mapping_range(eptp & PAGE_MASK,
kvm_fill_hv_flush_list_func, (void *)range);
else
- return hyperv_flush_guest_mapping(ept_pointer & PAGE_MASK);
+ return hyperv_flush_guest_mapping(eptp & PAGE_MASK);
}
static int hv_remote_flush_tlb_with_range(struct kvm *kvm,
@@ -533,12 +532,11 @@ static int hv_remote_flush_tlb_with_range(struct kvm *kvm,
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_tlb_with_range(
- kvm, vcpu, range);
+ ret |= hv_remote_flush_eptp(to_vmx(vcpu)->ept_pointer,
+ range);
}
- } else {
- ret = __hv_remote_flush_tlb_with_range(kvm,
- kvm_get_vcpu(kvm, 0), range);
+ } else if (VALID_PAGE(to_kvm_vmx(kvm)->hv_tlb_eptp)) {
+ ret = hv_remote_flush_eptp(to_kvm_vmx(kvm)->hv_tlb_eptp, range);
}
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 a2d143276603..9a25e83f8b96 100644
--- a/arch/x86/kvm/vmx/vmx.h
+++ b/arch/x86/kvm/vmx/vmx.h
@@ -301,6 +301,7 @@ struct kvm_vmx {
bool ept_identity_pagetable_done;
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 21:25 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 ` Sean Christopherson [this message]
2020-11-12 10:27 ` [PATCH v3 02/11] KVM: VMX: Track common EPTP for Hyper-V's paravirt TLB flush 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 ` [PATCH v3 06/11] KVM: VMX: Invalidate hv_tlb_eptp to denote an EPTP mismatch Sean Christopherson
2020-11-12 10:50 ` 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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