diff options
| author | Sean Christopherson <seanjc@google.com> | 2021-06-07 12:01:58 +0300 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2021-06-17 13:09:46 -0400 |
| commit | c7313155bf11906ad75ae0edc4a97bf93d69c275 (patch) | |
| tree | b1439c302ce116a7c3503f592a03a1ca780e77c1 /arch/x86/include/asm/kvm_host.h | |
| parent | a36dbec67e26febc1fc551f4819e3c058b25e79c (diff) | |
KVM: x86: Always load PDPTRs on CR3 load for SVM w/o NPT and a PAE guest
Kill off pdptrs_changed() and instead go through the full kvm_set_cr3()
for PAE guest, even if the new CR3 is the same as the current CR3. For
VMX, and SVM with NPT enabled, the PDPTRs are unconditionally marked as
unavailable after VM-Exit, i.e. the optimization is dead code except for
SVM without NPT.
In the unlikely scenario that anyone cares about SVM without NPT _and_ a
PAE guest, they've got bigger problems if their guest is loading the same
CR3 so frequently that the performance of kvm_set_cr3() is notable,
especially since KVM's fast PGD switching means reloading the same CR3
does not require a full rebuild. Given that PAE and PCID are mutually
exclusive, i.e. a sync and flush are guaranteed in any case, the actual
benefits of the pdptrs_changed() optimization are marginal at best.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210607090203.133058-4-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/include/asm/kvm_host.h')
| -rw-r--r-- | arch/x86/include/asm/kvm_host.h | 1 |
1 files changed, 0 insertions, 1 deletions
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 95b254b5a523..601e00876b38 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -1506,7 +1506,6 @@ unsigned long kvm_mmu_calculate_default_mmu_pages(struct kvm *kvm); void kvm_mmu_change_mmu_pages(struct kvm *kvm, unsigned long kvm_nr_mmu_pages); int load_pdptrs(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu, unsigned long cr3); -bool pdptrs_changed(struct kvm_vcpu *vcpu); int emulator_write_phys(struct kvm_vcpu *vcpu, gpa_t gpa, const void *val, int bytes); |