KVM: x86: add support for UMIP

Add the CPUID bits, make the CR4.UMIP bit not reserved anymore, and
add UMIP support for instructions that are already emulated by KVM.

Reviewed-by: Wanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/include/asm/kvm_host.h

@@ -86,7 +86,7 @@
 			  | X86_CR4_PGE | X86_CR4_PCE | X86_CR4_OSFXSR | X86_CR4_PCIDE \
 			  | X86_CR4_OSXSAVE | X86_CR4_SMEP | X86_CR4_FSGSBASE \
 			  | X86_CR4_OSXMMEXCPT | X86_CR4_LA57 | X86_CR4_VMXE \
-			  | X86_CR4_SMAP | X86_CR4_PKE))
+			  | X86_CR4_SMAP | X86_CR4_PKE | X86_CR4_UMIP))
 
 #define CR8_RESERVED_BITS (~(unsigned long)X86_CR8_TPR)
 

arch/x86/kvm/cpuid.c

@@ -387,8 +387,8 @@ static inline int __do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
 
 	/* cpuid 7.0.ecx*/
 	const u32 kvm_cpuid_7_0_ecx_x86_features =
-		F(AVX512VBMI) | F(LA57) | F(PKU) |
-		0 /*OSPKE*/ | F(AVX512_VPOPCNTDQ);
+		F(AVX512VBMI) | F(LA57) | F(PKU) | 0 /*OSPKE*/ |
+		F(AVX512_VPOPCNTDQ) | F(UMIP);
 
 	/* cpuid 7.0.edx*/
 	const u32 kvm_cpuid_7_0_edx_x86_features =

arch/x86/kvm/emulate.c

@@ -3720,6 +3720,10 @@ static int emulate_store_desc_ptr(struct x86_emulate_ctxt *ctxt,
 {
 	struct desc_ptr desc_ptr;
 
+	if ((ctxt->ops->get_cr(ctxt, 4) & X86_CR4_UMIP) &&
+	    ctxt->ops->cpl(ctxt) > 0)
+		return emulate_gp(ctxt, 0);
+
 	if (ctxt->mode == X86EMUL_MODE_PROT64)
 		ctxt->op_bytes = 8;
 	get(ctxt, &desc_ptr);
@@ -3779,6 +3783,10 @@ static int em_lidt(struct x86_emulate_ctxt *ctxt)
 
 static int em_smsw(struct x86_emulate_ctxt *ctxt)
 {
+	if ((ctxt->ops->get_cr(ctxt, 4) & X86_CR4_UMIP) &&
+	    ctxt->ops->cpl(ctxt) > 0)
+		return emulate_gp(ctxt, 0);
+
 	if (ctxt->dst.type == OP_MEM)
 		ctxt->dst.bytes = 2;
 	ctxt->dst.val = ctxt->ops->get_cr(ctxt, 0);

arch/x86/kvm/x86.c

@@ -794,6 +794,9 @@ int kvm_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4)
 	if (!guest_cpuid_has(vcpu, X86_FEATURE_LA57) && (cr4 & X86_CR4_LA57))
 		return 1;
 
+	if (!guest_cpuid_has(vcpu, X86_FEATURE_UMIP) && (cr4 & X86_CR4_UMIP))
+		return 1;
+
 	if (is_long_mode(vcpu)) {
 		if (!(cr4 & X86_CR4_PAE))
 			return 1;