[PATCH 09/15] KVM: nVMX: Don't speculatively write APIC-access page address

Sean Christopherson
2019-05-07T16:07:04Z

If nested_get_vmcs12_pages() fails to map L1's APIC_ACCESS_ADDR into
L2, then it disables SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES in vmcs02.
In other words, the APIC_ACCESS_ADDR in vmcs02 is guaranteed to be
written with the correct value before being consumed by hardware, drop
the unneessary VMWRITE.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
arch/x86/kvm/vmx/nested.c | 8 --------
1 file changed, 8 deletions(-)

diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 32d233dee067..29892c560771 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -2082,14 +2082,6 @@ static void prepare_vmcs02_early(struct vcpu_vmx *vmx, struct vmcs12 *vmcs12)
vmcs_write16(GUEST_INTR_STATUS,
vmcs12->guest_intr_status);

- /*
- * Write an illegal value to APIC_ACCESS_ADDR. Later,
- * nested_get_vmcs12_pages will either fix it up or
- * remove the VM execution control.
- */
- if (exec_control & SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES)
- vmcs_write64(APIC_ACCESS_ADDR, -1ull);
-
vmcs_write32(SECONDARY_VM_EXEC_CONTROL, exec_control);
}

--
2.21.0