KVM: VMX: Allow the guest to own some cr0 bits

We will use this later to give the guest ownership of cr0.ts.

Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 9 insertions, 0 deletions

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 4c7177c489ac..dbcdb55094f7 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -1653,6 +1653,14 @@ static void vmx_flush_tlb(struct kvm_vcpu *vcpu)
                 ept_sync_context(construct_eptp(vcpu->arch.mmu.root_hpa));
 }
 
+static void vmx_decache_cr0_guest_bits(struct kvm_vcpu *vcpu)
+{
+        ulong cr0_guest_owned_bits = vcpu->arch.cr0_guest_owned_bits;
+
+        vcpu->arch.cr0 &= ~cr0_guest_owned_bits;
+        vcpu->arch.cr0 |= vmcs_readl(GUEST_CR0) & cr0_guest_owned_bits;
+}
+
 static void vmx_decache_cr4_guest_bits(struct kvm_vcpu *vcpu)
 {
         ulong cr4_guest_owned_bits = vcpu->arch.cr4_guest_owned_bits;
@@ -4106,6 +4114,7 @@ static struct kvm_x86_ops vmx_x86_ops = {
         .set_segment = vmx_set_segment,
         .get_cpl = vmx_get_cpl,
         .get_cs_db_l_bits = vmx_get_cs_db_l_bits,
+        .decache_cr0_guest_bits = vmx_decache_cr0_guest_bits,
         .decache_cr4_guest_bits = vmx_decache_cr4_guest_bits,
         .set_cr0 = vmx_set_cr0,
         .set_cr3 = vmx_set_cr3,