KVM: Add accessor for reading cr4 (or some bits of cr4)

Some bits of cr4 can be owned by the guest on vmx, so when we read them,
we copy them to the vcpu structure.  In preparation for making the set of
guest-owned bits dynamic, use helpers to access these bits so we don't need
to know where the bit resides.

No changes to svm since all bits are host-owned there.

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

1 files changed, 8 insertions, 5 deletions

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index efbb614ccd36..284e905c59d3 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -1615,8 +1615,10 @@ static void vmx_flush_tlb(struct kvm_vcpu *vcpu)
 
 static void vmx_decache_cr4_guest_bits(struct kvm_vcpu *vcpu)
 {
-        vcpu->arch.cr4 &= KVM_GUEST_CR4_MASK;
-        vcpu->arch.cr4 |= vmcs_readl(GUEST_CR4) & ~KVM_GUEST_CR4_MASK;
+        ulong cr4_guest_owned_bits = vcpu->arch.cr4_guest_owned_bits;
+
+        vcpu->arch.cr4 &= ~cr4_guest_owned_bits;
+        vcpu->arch.cr4 |= vmcs_readl(GUEST_CR4) & cr4_guest_owned_bits;
 }
 
 static void ept_load_pdptrs(struct kvm_vcpu *vcpu)
@@ -1661,7 +1663,7 @@ static void ept_update_paging_mode_cr0(unsigned long *hw_cr0,
                              (CPU_BASED_CR3_LOAD_EXITING |
                               CPU_BASED_CR3_STORE_EXITING));
                 vcpu->arch.cr0 = cr0;
-                vmx_set_cr4(vcpu, vcpu->arch.cr4);
+                vmx_set_cr4(vcpu, kvm_read_cr4(vcpu));
         } else if (!is_paging(vcpu)) {
                 /* From nonpaging to paging */
                 vmcs_write32(CPU_BASED_VM_EXEC_CONTROL,
@@ -1669,7 +1671,7 @@ static void ept_update_paging_mode_cr0(unsigned long *hw_cr0,
                              ~(CPU_BASED_CR3_LOAD_EXITING |
                                CPU_BASED_CR3_STORE_EXITING));
                 vcpu->arch.cr0 = cr0;
-                vmx_set_cr4(vcpu, vcpu->arch.cr4);
+                vmx_set_cr4(vcpu, kvm_read_cr4(vcpu));
         }
 
         if (!(cr0 & X86_CR0_WP))
@@ -2420,6 +2422,7 @@ static int vmx_vcpu_setup(struct vcpu_vmx *vmx)
 
         vmcs_writel(CR0_GUEST_HOST_MASK, ~0UL);
         vmcs_writel(CR4_GUEST_HOST_MASK, KVM_GUEST_CR4_MASK);
+        vmx->vcpu.arch.cr4_guest_owned_bits = ~KVM_GUEST_CR4_MASK;
 
         tsc_base = vmx->vcpu.kvm->arch.vm_init_tsc;
         rdtscll(tsc_this);
@@ -3050,7 +3053,7 @@ static int handle_dr(struct kvm_vcpu *vcpu)
                                 vcpu->arch.eff_db[dr] = val;
                         break;
                 case 4 ... 5:
-                        if (vcpu->arch.cr4 & X86_CR4_DE)
+                        if (kvm_read_cr4_bits(vcpu, X86_CR4_DE))
                                 kvm_queue_exception(vcpu, UD_VECTOR);
                         break;
                 case 6: