KVM dynamically toggles SECONDARY_EXEC_DESC to intercept (a subset of)
instructions that are subject to User-Mode Instruction Prevention, i.e.
VMCS.SECONDARY_EXEC_DESC == CR4.UMIP when emulating UMIP. Preset the
VMCS control when preparing vmcs02 to avoid unnecessarily VMWRITEs,
e.g. KVM will clear VMCS.SECONDARY_EXEC_DESC in prepare_vmcs02_early()
and then set it in vmx_set_cr4().
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
/* VMCS shadowing for L2 is emulated for now */
exec_control &= ~SECONDARY_EXEC_SHADOW_VMCS;
/* VMCS shadowing for L2 is emulated for now */
exec_control &= ~SECONDARY_EXEC_SHADOW_VMCS;
+ /*
+ * Preset *DT exiting when emulating UMIP, so that vmx_set_cr4()
+ * will not have to rewrite the controls just for this bit.
+ */
+ if (!boot_cpu_has(X86_FEATURE_UMIP) && vmx_umip_emulated() &&
+ (vmcs12->guest_cr4 & X86_CR4_UMIP))
+ exec_control |= SECONDARY_EXEC_DESC;
+
if (exec_control & SECONDARY_EXEC_VIRTUAL_INTR_DELIVERY)
vmcs_write16(GUEST_INTR_STATUS,
vmcs12->guest_intr_status);
if (exec_control & SECONDARY_EXEC_VIRTUAL_INTR_DELIVERY)
vmcs_write16(GUEST_INTR_STATUS,
vmcs12->guest_intr_status);