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| author | Sean Christopherson <seanjc@google.com> | 2021-06-09 16:42:21 -0700 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2021-06-17 13:09:51 -0400 |
| commit | 07ffaf343e34b555c9e7ea39a9c81c439a706f13 (patch) | |
| tree | 2b066c210be7d604078ccb46d955c922e22f909e /arch/x86/kvm/hyperv.c | |
| parent | 8f7663cea285ef41306fb3ea5b5a48e8e38a681d (diff) | |
| download | lwn-07ffaf343e34b555c9e7ea39a9c81c439a706f13.tar.gz lwn-07ffaf343e34b555c9e7ea39a9c81c439a706f13.zip | |
KVM: nVMX: Sync all PGDs on nested transition with shadow paging
Trigger a full TLB flush on behalf of the guest on nested VM-Enter and
VM-Exit when VPID is disabled for L2. kvm_mmu_new_pgd() syncs only the
current PGD, which can theoretically leave stale, unsync'd entries in a
previous guest PGD, which could be consumed if L2 is allowed to load CR3
with PCID_NOFLUSH=1.
Rename KVM_REQ_HV_TLB_FLUSH to KVM_REQ_TLB_FLUSH_GUEST so that it can
be utilized for its obvious purpose of emulating a guest TLB flush.
Note, there is no change the actual TLB flush executed by KVM, even
though the fast PGD switch uses KVM_REQ_TLB_FLUSH_CURRENT. When VPID is
disabled for L2, vpid02 is guaranteed to be '0', and thus
nested_get_vpid02() will return the VPID that is shared by L1 and L2.
Generate the request outside of kvm_mmu_new_pgd(), as getting the common
helper to correctly identify which requested is needed is quite painful.
E.g. using KVM_REQ_TLB_FLUSH_GUEST when nested EPT is in play is wrong as
a TLB flush from the L1 kernel's perspective does not invalidate EPT
mappings. And, by using KVM_REQ_TLB_FLUSH_GUEST, nVMX can do future
simplification by moving the logic into nested_vmx_transition_tlb_flush().
Fixes: 41fab65e7c44 ("KVM: nVMX: Skip MMU sync on nested VMX transition when possible")
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210609234235.1244004-2-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/hyperv.c')
| -rw-r--r-- | arch/x86/kvm/hyperv.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c index 4f911dca7dd6..b07592ca92f0 100644 --- a/arch/x86/kvm/hyperv.c +++ b/arch/x86/kvm/hyperv.c @@ -1829,7 +1829,7 @@ static u64 kvm_hv_flush_tlb(struct kvm_vcpu *vcpu, struct kvm_hv_hcall *hc, bool * vcpu->arch.cr3 may not be up-to-date for running vCPUs so we can't * analyze it here, flush TLB regardless of the specified address space. */ - kvm_make_vcpus_request_mask(kvm, KVM_REQ_HV_TLB_FLUSH, + kvm_make_vcpus_request_mask(kvm, KVM_REQ_TLB_FLUSH_GUEST, NULL, vcpu_mask, &hv_vcpu->tlb_flush); ret_success: |