KVM: x86: Make register state after reset conform to specification

VMX behaves now as SVM wrt to FPU initialization. Code has been moved to
generic code path. General-purpose registers are now cleared on reset and
INIT.  SVM code properly initializes EDX.

Signed-off-by: Julian Stecklina <jsteckli@os.inf.tu-dresden.de>
Signed-off-by: Gleb Natapov <gleb@redhat.com>

arch/x86/kvm/cpuid.c

@@ -661,6 +661,7 @@ 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)
 {

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>
@@ -1193,6 +1194,8 @@ 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;
+	u32 eax = 1;
 
 	init_vmcb(svm);
 
@@ -1201,8 +1204,9 @@ 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;
 }
@@ -1259,10 +1263,6 @@ static struct kvm_vcpu *svm_create_vcpu(struct kvm *kvm, unsigned int id)
 	svm->asid_generation = 0;
 	init_vmcb(svm);
 
-	err = fx_init(&svm->vcpu);
-	if (err)
-		goto free_page4;
-
 	svm->vcpu.arch.apic_base = 0xfee00000 | MSR_IA32_APICBASE_ENABLE;
 	if (kvm_vcpu_is_bsp(&svm->vcpu))
 		svm->vcpu.arch.apic_base |= MSR_IA32_APICBASE_BSP;
@@ -1271,8 +1271,6 @@ static struct kvm_vcpu *svm_create_vcpu(struct kvm *kvm, unsigned int id)
 
 	return &svm->vcpu;
 
-free_page4:
-	__free_page(hsave_page);
 free_page3:
 	__free_pages(nested_msrpm_pages, MSRPM_ALLOC_ORDER);
 free_page2:

arch/x86/kvm/vmx.c

@@ -3918,8 +3918,6 @@ 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));
-
 	vmx->rmode.vm86_active = 0;
 
 	vmx->soft_vnmi_blocked = 0;
@@ -3931,10 +3929,6 @@ 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);
@@ -3975,7 +3969,6 @@ 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_GDTR_BASE, 0);
 	vmcs_write32(GUEST_GDTR_LIMIT, 0xffff);
@@ -4025,7 +4018,6 @@ static int vmx_vcpu_reset(struct kvm_vcpu *vcpu)
 	/* HACK: Don't enable emulation on guest boot/reset */
 	vmx->emulation_required = 0;
 
-out:
 	return ret;
 }
 

arch/x86/kvm/x86.c

@@ -6461,6 +6461,10 @@ static int kvm_vcpu_reset(struct kvm_vcpu *vcpu)
 
 	kvm_pmu_reset(vcpu);
 
+	memset(vcpu->arch.regs, 0, sizeof(vcpu->arch.regs));
+	vcpu->arch.regs_avail = ~0;
+	vcpu->arch.regs_dirty = ~0;
+
 	return kvm_x86_ops->vcpu_reset(vcpu);
 }
 
@@ -6629,11 +6633,17 @@ int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu)
 	if (!zalloc_cpumask_var(&vcpu->arch.wbinvd_dirty_mask, GFP_KERNEL))
 		goto fail_free_mce_banks;
 
+	r = fx_init(vcpu);
+	if (r)
+		goto fail_free_wbinvd_dirty_mask;
+
 	vcpu->arch.ia32_tsc_adjust_msr = 0x0;
 	kvm_async_pf_hash_reset(vcpu);
 	kvm_pmu_init(vcpu);
 
 	return 0;
+fail_free_wbinvd_dirty_mask:
+	free_cpumask_var(vcpu->arch.wbinvd_dirty_mask);
 fail_free_mce_banks:
 	kfree(vcpu->arch.mce_banks);
 fail_free_lapic: