[PATCH v2] KVM: x86: Make register state after reset conform to specification

[Julian Stecklina <jsteckli@os.inf.tu-dresden.de>]

Floating point initialization is moved to kvm_arch_vcpu_init. Added general purpose
register clearing to the same function. SVM code now properly initializes
EDX.

Signed-off-by: Julian Stecklina <jsteckli@os.inf.tu-dresden.de>
---
 arch/x86/kvm/cpuid.c |  1 +
 arch/x86/kvm/svm.c   |  7 +++++--
 arch/x86/kvm/vmx.c   |  7 +------
 arch/x86/kvm/x86.c   | 12 +++++++++++-
 4 files changed, 18 insertions(+), 9 deletions(-)

diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 0595f13..aa468c2 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -659,6 +659,7 @@ void kvm_cpuid(struct kvm_vcpu *vcpu, u32 *eax, u32 *ebx, u32 *ecx, u32 *edx)
 	} else
 		*eax = *ebx = *ecx = *edx = 0;
 }
+EXPORT_SYMBOL_GPL(kvm_cpuid);
 
 void kvm_emulate_cpuid(struct kvm_vcpu *vcpu)
 {
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index baead95..642213a 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -20,6 +20,7 @@
 #include "mmu.h"
 #include "kvm_cache_regs.h"
 #include "x86.h"
+#include "cpuid.h"
 
 #include <linux/module.h>
 #include <linux/mod_devicetable.h>
@@ -1190,6 +1191,7 @@ static void init_vmcb(struct vcpu_svm *svm)
 static int svm_vcpu_reset(struct kvm_vcpu *vcpu)
 {
 	struct vcpu_svm *svm = to_svm(vcpu);
+	u32 dummy, eax;
 
 	init_vmcb(svm);
 
@@ -1198,8 +1200,9 @@ static int svm_vcpu_reset(struct kvm_vcpu *vcpu)
 		svm->vmcb->save.cs.base = svm->vcpu.arch.sipi_vector << 12;
 		svm->vmcb->save.cs.selector = svm->vcpu.arch.sipi_vector << 8;
 	}
-	vcpu->arch.regs_avail = ~0;
-	vcpu->arch.regs_dirty = ~0;
+
+	kvm_cpuid(vcpu, &eax, &dummy, &dummy, &dummy);
+	kvm_register_write(vcpu, VCPU_REGS_RDX, eax);
 
 	return 0;
 }
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index ff66a3b..363fb03 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -3942,7 +3942,7 @@ static int vmx_vcpu_reset(struct kvm_vcpu *vcpu)
 	u64 msr;
 	int ret;
 
-	vcpu->arch.regs_avail = ~((1 << VCPU_REGS_RIP) | (1 << VCPU_REGS_RSP));
+	vcpu->arch.regs_avail = ~(1 << VCPU_REGS_RIP);
 
 	vmx->rmode.vm86_active = 0;
 
@@ -3955,10 +3955,6 @@ static int vmx_vcpu_reset(struct kvm_vcpu *vcpu)
 		msr |= MSR_IA32_APICBASE_BSP;
 	kvm_set_apic_base(&vmx->vcpu, msr);
 
-	ret = fx_init(&vmx->vcpu);
-	if (ret != 0)
-		goto out;
-
 	vmx_segment_cache_clear(vmx);
 
 	seg_setup(VCPU_SREG_CS);
@@ -3999,7 +3995,6 @@ static int vmx_vcpu_reset(struct kvm_vcpu *vcpu)
 		kvm_rip_write(vcpu, 0xfff0);
 	else
 		kvm_rip_write(vcpu, 0);
-	kvm_register_write(vcpu, VCPU_REGS_RSP, 0);
 
 	vmcs_writel(GUEST_DR7, 0x400);
 
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 2966c84..9640ea5 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -6045,6 +6045,8 @@ void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu)
 
 int kvm_arch_vcpu_reset(struct kvm_vcpu *vcpu)
 {
+	int ret;
+
 	atomic_set(&vcpu->arch.nmi_queued, 0);
 	vcpu->arch.nmi_pending = 0;
 	vcpu->arch.nmi_injected = false;
@@ -6066,7 +6068,15 @@ int kvm_arch_vcpu_reset(struct kvm_vcpu *vcpu)
 
 	kvm_pmu_reset(vcpu);
 
-	return kvm_x86_ops->vcpu_reset(vcpu);
+	memset(vcpu->arch.regs, 0, sizeof(vcpu->arch.regs));
+	vcpu->arch.regs_avail = ~0;
+	vcpu->arch.regs_dirty = ~0;
+
+	if ((ret = fx_init(vcpu)) != 0) goto out;
+
+	ret = kvm_x86_ops->vcpu_reset(vcpu);
+out:
+	return ret;
 }
 
 int kvm_arch_hardware_enable(void *garbage)
-- 
1.7.11.7