KVM: x86: Move XSETBV emulation to common code

Move the entirety of XSETBV emulation to x86.c, and assign the
function directly to both VMX's and SVM's exit handlers, i.e. drop the
unnecessary trampolines.

No functional change intended.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210205005750.3841462-6-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/include/asm/kvm_host.h

@@ -1550,7 +1550,7 @@ void kvm_get_dr(struct kvm_vcpu *vcpu, int dr, unsigned long *val);
 unsigned long kvm_get_cr8(struct kvm_vcpu *vcpu);
 void kvm_lmsw(struct kvm_vcpu *vcpu, unsigned long msw);
 void kvm_get_cs_db_l_bits(struct kvm_vcpu *vcpu, int *db, int *l);
-int kvm_set_xcr(struct kvm_vcpu *vcpu, u32 index, u64 xcr);
+int kvm_emulate_xsetbv(struct kvm_vcpu *vcpu);
 
 int kvm_get_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr);
 int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr);

arch/x86/kvm/svm/svm.c

@@ -2344,15 +2344,6 @@ static int wbinvd_interception(struct kvm_vcpu *vcpu)
 	return kvm_emulate_wbinvd(vcpu);
 }
 
-static int xsetbv_interception(struct kvm_vcpu *vcpu)
-{
-	u64 new_bv = kvm_read_edx_eax(vcpu);
-	u32 index = kvm_rcx_read(vcpu);
-
-	int err = kvm_set_xcr(vcpu, index, new_bv);
-	return kvm_complete_insn_gp(vcpu, err);
-}
-
 static int rdpru_interception(struct kvm_vcpu *vcpu)
 {
 	kvm_queue_exception(vcpu, UD_VECTOR);
@@ -3154,7 +3145,7 @@ static int (*const svm_exit_handlers[])(struct kvm_vcpu *vcpu) = {
 	[SVM_EXIT_WBINVD]                       = wbinvd_interception,
 	[SVM_EXIT_MONITOR]			= monitor_interception,
 	[SVM_EXIT_MWAIT]			= mwait_interception,
-	[SVM_EXIT_XSETBV]			= xsetbv_interception,
+	[SVM_EXIT_XSETBV]			= kvm_emulate_xsetbv,
 	[SVM_EXIT_RDPRU]			= rdpru_interception,
 	[SVM_EXIT_EFER_WRITE_TRAP]		= efer_trap,
 	[SVM_EXIT_CR0_WRITE_TRAP]		= cr_trap,

arch/x86/kvm/vmx/vmx.c

@@ -5216,15 +5216,6 @@ static int handle_wbinvd(struct kvm_vcpu *vcpu)
 	return kvm_emulate_wbinvd(vcpu);
 }
 
-static int handle_xsetbv(struct kvm_vcpu *vcpu)
-{
-	u64 new_bv = kvm_read_edx_eax(vcpu);
-	u32 index = kvm_rcx_read(vcpu);
-
-	int err = kvm_set_xcr(vcpu, index, new_bv);
-	return kvm_complete_insn_gp(vcpu, err);
-}
-
 static int handle_apic_access(struct kvm_vcpu *vcpu)
 {
 	if (likely(fasteoi)) {
@@ -5686,7 +5677,7 @@ static int (*kvm_vmx_exit_handlers[])(struct kvm_vcpu *vcpu) = {
 	[EXIT_REASON_APIC_WRITE]              = handle_apic_write,
 	[EXIT_REASON_EOI_INDUCED]             = handle_apic_eoi_induced,
 	[EXIT_REASON_WBINVD]                  = handle_wbinvd,
-	[EXIT_REASON_XSETBV]                  = handle_xsetbv,
+	[EXIT_REASON_XSETBV]                  = kvm_emulate_xsetbv,
 	[EXIT_REASON_TASK_SWITCH]             = handle_task_switch,
 	[EXIT_REASON_MCE_DURING_VMENTRY]      = handle_machine_check,
 	[EXIT_REASON_GDTR_IDTR]		      = handle_desc,

arch/x86/kvm/x86.c

@@ -985,14 +985,17 @@ static int __kvm_set_xcr(struct kvm_vcpu *vcpu, u32 index, u64 xcr)
 	return 0;
 }
 
-int kvm_set_xcr(struct kvm_vcpu *vcpu, u32 index, u64 xcr)
+int kvm_emulate_xsetbv(struct kvm_vcpu *vcpu)
 {
-	if (static_call(kvm_x86_get_cpl)(vcpu) == 0)
-		return __kvm_set_xcr(vcpu, index, xcr);
+	if (static_call(kvm_x86_get_cpl)(vcpu) != 0 ||
+	    __kvm_set_xcr(vcpu, kvm_rcx_read(vcpu), kvm_read_edx_eax(vcpu))) {
+		kvm_inject_gp(vcpu, 0);
+		return 1;
+	}
 
-	return 1;
+	return kvm_skip_emulated_instruction(vcpu);
 }
-EXPORT_SYMBOL_GPL(kvm_set_xcr);
+EXPORT_SYMBOL_GPL(kvm_emulate_xsetbv);
 
 bool kvm_is_valid_cr4(struct kvm_vcpu *vcpu, unsigned long cr4)
 {