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KVM: VMX: optimize #PF injection when MAXPHYADDR does not match

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Ignore non-present page faults, since those cannot have reserved
bits set.

When running access.flat with "-cpu Haswell,phys-bits=36", the
number of trapped page faults goes down from 8872644 to 3978948.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20200710154811.418214-9-mgamal@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Paolo Bonzini
2020-07-10 17:48:10 +02:00
parent 1dbf5d68af
commit 8c4182bd27
1 changed files with 10 additions and 0 deletions
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10
arch/x86/kvm/vmx/vmx.c
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@@ -4355,6 +4355,16 @@ static void init_vmcs(struct vcpu_vmx *vmx)
vmx->pt_desc.guest.output_mask = 0x7F; vmx->pt_desc.guest.output_mask = 0x7F;
vmcs_write64(GUEST_IA32_RTIT_CTL, 0); vmcs_write64(GUEST_IA32_RTIT_CTL, 0);
} }
/*
* If EPT is enabled, #PF is only trapped if MAXPHYADDR is mismatched
* between guest and host. In that case we only care about present
* faults.
*/
if (enable_ept) {
vmcs_write32(PAGE_FAULT_ERROR_CODE_MASK, PFERR_PRESENT_MASK);
vmcs_write32(PAGE_FAULT_ERROR_CODE_MATCH, PFERR_PRESENT_MASK);
}
} }
static void vmx_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event) static void vmx_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event)