linux-kernel - [PATCH 15/23] KVM: x86: Move XSETBV emulation to common code

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Date:   Tue,  2 Mar 2021 14:33:35 -0500
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Cc:     seanjc@...gle.com
Subject: [PATCH 15/23] KVM: x86: Move XSETBV emulation to common code

From: Sean Christopherson <seanjc@...gle.com>

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@...gle.com>
Message-Id: <20210205005750.3841462-6-seanjc@...gle.com>
Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
---
 arch/x86/include/asm/kvm_host.h |  2 +-
 arch/x86/kvm/svm/svm.c          | 11 +----------
 arch/x86/kvm/vmx/vmx.c          | 11 +----------
 arch/x86/kvm/x86.c              | 13 ++++++++-----
 4 files changed, 11 insertions(+), 26 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 85ccbd4b7c52..b396e854c7db 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1542,7 +1542,7 @@ 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);
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 5815fedf978e..fcea45f40d76 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -2346,15 +2346,6 @@ 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);
@@ -3156,7 +3147,7 @@ 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,
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 50810d471462..0df836897447 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/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,
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 1d2bc89431a2..8dc69ff3d205 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -984,14 +984,17 @@ 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)
 {
-- 
2.26.2