Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull KVM fixes from Radim Krčmář:
 "Four fixes for bugs found by syzkaller on x86, all for stable"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: x86: check for pic and ioapic presence before use
  KVM: x86: fix out-of-bounds accesses of rtc_eoi map
  KVM: x86: drop error recovery in em_jmp_far and em_ret_far
  KVM: x86: fix out-of-bounds access in lapic

Author: torvalds

arch/x86/kvm/emulate.c

@@ -2105,16 +2105,10 @@ static int em_iret(struct x86_emulate_ctxt *ctxt)
 static int em_jmp_far(struct x86_emulate_ctxt *ctxt)
 {
 	int rc;
-	unsigned short sel, old_sel;
-	struct desc_struct old_desc, new_desc;
-	const struct x86_emulate_ops *ops = ctxt->ops;
+	unsigned short sel;
+	struct desc_struct new_desc;
 	u8 cpl = ctxt->ops->cpl(ctxt);
 
-	/* Assignment of RIP may only fail in 64-bit mode */
-	if (ctxt->mode == X86EMUL_MODE_PROT64)
-		ops->get_segment(ctxt, &old_sel, &old_desc, NULL,
-				 VCPU_SREG_CS);
-
 	memcpy(&sel, ctxt->src.valptr + ctxt->op_bytes, 2);
 
 	rc = __load_segment_descriptor(ctxt, sel, VCPU_SREG_CS, cpl,
@@ -2124,12 +2118,10 @@ static int em_jmp_far(struct x86_emulate_ctxt *ctxt)
 		return rc;
 
 	rc = assign_eip_far(ctxt, ctxt->src.val, &new_desc);
-	if (rc != X86EMUL_CONTINUE) {
-		WARN_ON(ctxt->mode != X86EMUL_MODE_PROT64);
-		/* assigning eip failed; restore the old cs */
-		ops->set_segment(ctxt, old_sel, &old_desc, 0, VCPU_SREG_CS);
-		return rc;
-	}
+	/* Error handling is not implemented. */
+	if (rc != X86EMUL_CONTINUE)
+		return X86EMUL_UNHANDLEABLE;
+
 	return rc;
 }
 
@@ -2189,14 +2181,8 @@ static int em_ret_far(struct x86_emulate_ctxt *ctxt)
 {
 	int rc;
 	unsigned long eip, cs;
-	u16 old_cs;
 	int cpl = ctxt->ops->cpl(ctxt);
-	struct desc_struct old_desc, new_desc;
-	const struct x86_emulate_ops *ops = ctxt->ops;
-
-	if (ctxt->mode == X86EMUL_MODE_PROT64)
-		ops->get_segment(ctxt, &old_cs, &old_desc, NULL,
-				 VCPU_SREG_CS);
+	struct desc_struct new_desc;
 
 	rc = emulate_pop(ctxt, &eip, ctxt->op_bytes);
 	if (rc != X86EMUL_CONTINUE)
@@ -2213,10 +2199,10 @@ static int em_ret_far(struct x86_emulate_ctxt *ctxt)
 	if (rc != X86EMUL_CONTINUE)
 		return rc;
 	rc = assign_eip_far(ctxt, eip, &new_desc);
-	if (rc != X86EMUL_CONTINUE) {
-		WARN_ON(ctxt->mode != X86EMUL_MODE_PROT64);
-		ops->set_segment(ctxt, old_cs, &old_desc, 0, VCPU_SREG_CS);
-	}
+	/* Error handling is not implemented. */
+	if (rc != X86EMUL_CONTINUE)
+		return X86EMUL_UNHANDLEABLE;
+
 	return rc;
 }
 

arch/x86/kvm/ioapic.c

@@ -94,7 +94,7 @@ static unsigned long ioapic_read_indirect(struct kvm_ioapic *ioapic,
 static void rtc_irq_eoi_tracking_reset(struct kvm_ioapic *ioapic)
 {
 	ioapic->rtc_status.pending_eoi = 0;
-	bitmap_zero(ioapic->rtc_status.dest_map.map, KVM_MAX_VCPUS);
+	bitmap_zero(ioapic->rtc_status.dest_map.map, KVM_MAX_VCPU_ID);
 }
 
 static void kvm_rtc_eoi_tracking_restore_all(struct kvm_ioapic *ioapic);

arch/x86/kvm/ioapic.h

@@ -42,13 +42,13 @@ struct kvm_vcpu;
 
 struct dest_map {
 	/* vcpu bitmap where IRQ has been sent */
-	DECLARE_BITMAP(map, KVM_MAX_VCPUS);
+	DECLARE_BITMAP(map, KVM_MAX_VCPU_ID);
 
 	/*
 	 * Vector sent to a given vcpu, only valid when
 	 * the vcpu's bit in map is set
 	 */
-	u8 vectors[KVM_MAX_VCPUS];
+	u8 vectors[KVM_MAX_VCPU_ID];
 };
 
 

arch/x86/kvm/irq_comm.c

@@ -41,6 +41,15 @@ static int kvm_set_pic_irq(struct kvm_kernel_irq_routing_entry *e,
 			   bool line_status)
 {
 	struct kvm_pic *pic = pic_irqchip(kvm);
+
+	/*
+	 * XXX: rejecting pic routes when pic isn't in use would be better,
+	 * but the default routing table is installed while kvm->arch.vpic is
+	 * NULL and KVM_CREATE_IRQCHIP can race with KVM_IRQ_LINE.
+	 */
+	if (!pic)
+		return -1;
+
 	return kvm_pic_set_irq(pic, e->irqchip.pin, irq_source_id, level);
 }
 
@@ -49,6 +58,10 @@ static int kvm_set_ioapic_irq(struct kvm_kernel_irq_routing_entry *e,
 			      bool line_status)
 {
 	struct kvm_ioapic *ioapic = kvm->arch.vioapic;
+
+	if (!ioapic)
+		return -1;
+
 	return kvm_ioapic_set_irq(ioapic, e->irqchip.pin, irq_source_id, level,
 				line_status);
 }

arch/x86/kvm/lapic.c

@@ -138,7 +138,7 @@ static inline bool kvm_apic_map_get_logical_dest(struct kvm_apic_map *map,
 		*mask = dest_id & 0xff;
 		return true;
 	case KVM_APIC_MODE_XAPIC_CLUSTER:
-		*cluster = map->xapic_cluster_map[dest_id >> 4];
+		*cluster = map->xapic_cluster_map[(dest_id >> 4) & 0xf];
 		*mask = dest_id & 0xf;
 		return true;
 	default: