[PATCH 5/7] Nested VMX patch 5 Simplify fpu handling

[oritw@xxxxxxxxxx]

From: Orit Wasserman <oritw@xxxxxxxxxx>

---
 arch/x86/kvm/vmx.c |   27 +++++++++++++++++----------
 1 files changed, 17 insertions(+), 10 deletions(-)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 8745d44..de1f596 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -1244,8 +1244,6 @@ static void update_exception_bitmap(struct kvm_vcpu *vcpu)
 	u32 eb;
 
 	eb = (1u << PF_VECTOR) | (1u << UD_VECTOR) | (1u << MC_VECTOR);
-	if (!vcpu->fpu_active)
-		eb |= 1u << NM_VECTOR;
 	/*
 	 * Unconditionally intercept #DB so we can maintain dr6 without
 	 * reading it every exit.
@@ -1463,10 +1461,6 @@ static void vmx_fpu_activate(struct kvm_vcpu *vcpu)
 	if (vcpu->fpu_active)
 		return;
 	vcpu->fpu_active = 1;
-	vmcs_clear_bits(GUEST_CR0, X86_CR0_TS);
-	if (vcpu->arch.cr0 & X86_CR0_TS)
-		vmcs_set_bits(GUEST_CR0, X86_CR0_TS);
-	update_exception_bitmap(vcpu);
 }
 
 static void vmx_fpu_deactivate(struct kvm_vcpu *vcpu)
@@ -1474,8 +1468,6 @@ static void vmx_fpu_deactivate(struct kvm_vcpu *vcpu)
 	if (!vcpu->fpu_active)
 		return;
 	vcpu->fpu_active = 0;
-	vmcs_set_bits(GUEST_CR0, X86_CR0_TS);
-	update_exception_bitmap(vcpu);
 }
 
 static unsigned long vmx_get_rflags(struct kvm_vcpu *vcpu)
@@ -2715,8 +2707,10 @@ static void vmx_set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3)
 
 	vmx_flush_tlb(vcpu);
 	vmcs_writel(GUEST_CR3, guest_cr3);
-	if (vcpu->arch.cr0 & X86_CR0_PE)
-		vmx_fpu_deactivate(vcpu);
+	if (vcpu->arch.cr0 & X86_CR0_PE) {
+		if (guest_cr3 != vmcs_readl(GUEST_CR3))
+			vmx_fpu_deactivate(vcpu);
+	}
 }
 
 static void vmx_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4)
@@ -5208,6 +5202,19 @@ static void vmx_vcpu_run(struct kvm_vcpu *vcpu)
 	if (vcpu->arch.switch_db_regs)
 		get_debugreg(vcpu->arch.dr6, 6);
 
+	if (vcpu->fpu_active) {
+		if (vmcs_readl(CR0_READ_SHADOW) & X86_CR0_TS)
+			vmcs_set_bits(GUEST_CR0, X86_CR0_TS);
+		else
+			vmcs_clear_bits(GUEST_CR0, X86_CR0_TS);
+			vmcs_write32(EXCEPTION_BITMAP,
+				     vmcs_read32(EXCEPTION_BITMAP) &  ~(1u << NM_VECTOR));
+	} else {
+		vmcs_set_bits(GUEST_CR0, X86_CR0_TS);
+		vmcs_write32(EXCEPTION_BITMAP,
+			     vmcs_read32(EXCEPTION_BITMAP) |  (1u << NM_VECTOR));
+	}
+
 	vmx->idt_vectoring_info = vmcs_read32(IDT_VECTORING_INFO_FIELD);
 	if (vmx->rmode.irq.pending)
 		fixup_rmode_irq(vmx);
-- 
1.6.0.4

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