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>

4 files changed, 18 insertions, 0 deletions

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index a4de557ad733..693046a7a12d 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -269,6 +269,7 @@ struct kvm_vcpu_arch {
         u32 regs_dirty;
 
         unsigned long cr0;
+        unsigned long cr0_guest_owned_bits;
         unsigned long cr2;
         unsigned long cr3;
         unsigned long cr4;
@@ -489,6 +490,7 @@ struct kvm_x86_ops {
         void (*set_segment)(struct kvm_vcpu *vcpu,
                             struct kvm_segment *var, int seg);
         void (*get_cs_db_l_bits)(struct kvm_vcpu *vcpu, int *db, int *l);
+        void (*decache_cr0_guest_bits)(struct kvm_vcpu *vcpu);
         void (*decache_cr4_guest_bits)(struct kvm_vcpu *vcpu);
         void (*set_cr0)(struct kvm_vcpu *vcpu, unsigned long cr0);
         void (*set_cr3)(struct kvm_vcpu *vcpu, unsigned long cr3);
diff --git a/arch/x86/kvm/kvm_cache_regs.h b/arch/x86/kvm/kvm_cache_regs.h
index f46859751b30..6b419a36cbd9 100644
--- a/arch/x86/kvm/kvm_cache_regs.h
+++ b/arch/x86/kvm/kvm_cache_regs.h
@@ -40,6 +40,8 @@ static inline u64 kvm_pdptr_read(struct kvm_vcpu *vcpu, int index)
 
 static inline ulong kvm_read_cr0_bits(struct kvm_vcpu *vcpu, ulong mask)
 {
+        if (mask & vcpu->arch.cr0_guest_owned_bits)
+                kvm_x86_ops->decache_cr0_guest_bits(vcpu);
         return vcpu->arch.cr0 & mask;
 }
 
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index d3246ce70ae8..3899c2d19830 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -956,6 +956,10 @@ static void svm_set_gdt(struct kvm_vcpu *vcpu, struct descriptor_table *dt)
         svm->vmcb->save.gdtr.base = dt->base ;
 }
 
+static void svm_decache_cr0_guest_bits(struct kvm_vcpu *vcpu)
+{
+}
+
 static void svm_decache_cr4_guest_bits(struct kvm_vcpu *vcpu)
 {
 }
@@ -2948,6 +2952,7 @@ static struct kvm_x86_ops svm_x86_ops = {
         .set_segment = svm_set_segment,
         .get_cpl = svm_get_cpl,
         .get_cs_db_l_bits = kvm_get_cs_db_l_bits,
+        .decache_cr0_guest_bits = svm_decache_cr0_guest_bits,
         .decache_cr4_guest_bits = svm_decache_cr4_guest_bits,
         .set_cr0 = svm_set_cr0,
         .set_cr3 = svm_set_cr3,
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,