diff mbox

[25/28] nVMX: Further fixes for lazy FPU loading

Message ID 201012081712.oB8HCkpY008822@rice.haifa.ibm.com (mailing list archive)
State New, archived
Headers show

Commit Message

Nadav Har'El Dec. 8, 2010, 5:12 p.m. UTC
None
diff mbox

Patch

--- .before/arch/x86/kvm/vmx.c	2010-12-08 18:56:52.000000000 +0200
+++ .after/arch/x86/kvm/vmx.c	2010-12-08 18:56:52.000000000 +0200
@@ -1098,6 +1098,15 @@  static void update_exception_bitmap(stru
 		eb &= ~(1u << PF_VECTOR); /* bypass_guest_pf = 0 */
 	if (vcpu->fpu_active)
 		eb &= ~(1u << NM_VECTOR);
+
+	/* When we are running a nested L2 guest and L1 specified for it a
+	 * certain exception bitmap, we must trap the same exceptions and pass
+	 * them to L1. When running L2, we will only handle the exceptions
+	 * specified above if L1 did not want them.
+	 */
+	if (is_guest_mode(vcpu))
+		eb |= get_vmcs12_fields(vcpu)->exception_bitmap;
+
 	vmcs_write32(EXCEPTION_BITMAP, eb);
 }
 
@@ -1415,8 +1424,19 @@  static void vmx_fpu_activate(struct kvm_
 	cr0 &= ~(X86_CR0_TS | X86_CR0_MP);
 	cr0 |= kvm_read_cr0_bits(vcpu, X86_CR0_TS | X86_CR0_MP);
 	vmcs_writel(GUEST_CR0, cr0);
-	update_exception_bitmap(vcpu);
 	vcpu->arch.cr0_guest_owned_bits = X86_CR0_TS;
+	if (is_guest_mode(vcpu)) {
+		/* While we (L0) no longer care about NM exceptions or cr0.TS
+		 * changes, our guest hypervisor (L1) might care in which case
+		 * we must trap them for it.
+		 */
+		u32 eb = vmcs_read32(EXCEPTION_BITMAP) & ~(1u << NM_VECTOR);
+		struct vmcs_fields *vmcs12 = get_vmcs12_fields(vcpu);
+		eb |= vmcs12->exception_bitmap;
+		vcpu->arch.cr0_guest_owned_bits &= ~vmcs12->cr0_guest_host_mask;
+		vmcs_write32(EXCEPTION_BITMAP, eb);
+	} else
+		update_exception_bitmap(vcpu);
 	vmcs_writel(CR0_GUEST_HOST_MASK, ~vcpu->arch.cr0_guest_owned_bits);
 }
 
@@ -1424,12 +1444,24 @@  static void vmx_decache_cr0_guest_bits(s
 
 static void vmx_fpu_deactivate(struct kvm_vcpu *vcpu)
 {
+	/* Note that there is no vcpu->fpu_active = 0 here. The caller must
+	 * set this *before* calling this function.
+	 */
 	vmx_decache_cr0_guest_bits(vcpu);
 	vmcs_set_bits(GUEST_CR0, X86_CR0_TS | X86_CR0_MP);
-	update_exception_bitmap(vcpu);
+	vmcs_write32(EXCEPTION_BITMAP,
+		vmcs_read32(EXCEPTION_BITMAP) | (1u << NM_VECTOR));
 	vcpu->arch.cr0_guest_owned_bits = 0;
 	vmcs_writel(CR0_GUEST_HOST_MASK, ~vcpu->arch.cr0_guest_owned_bits);
-	vmcs_writel(CR0_READ_SHADOW, vcpu->arch.cr0);
+	if (is_guest_mode(vcpu))
+		/* Unfortunately in nested mode we play with arch.cr0's PG
+		 * bit, so we musn't copy it all, just the relevant TS bit
+		 */
+		vmcs_writel(CR0_READ_SHADOW,
+			(vmcs_readl(CR0_READ_SHADOW) & ~X86_CR0_TS) |
+			(vcpu->arch.cr0 & X86_CR0_TS));
+	else
+		vmcs_writel(CR0_READ_SHADOW, vcpu->arch.cr0);
 }
 
 static unsigned long vmx_get_rflags(struct kvm_vcpu *vcpu)