KVM: Break dependency between vcpu index in vcpus array and vcpu_id.

Archs are free to use vcpu_id as they see fit. For x86 it is used as vcpu's apic id. New ioctl is added to configure boot vcpu id that was assumed to be 0 till now. Signed-off-by: Gleb Natapov <gleb@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>

KVM: Break dependency between vcpu index in vcpus array and vcpu_id.
Archs are free to use vcpu_id as they see fit. For x86 it is used as vcpu's apic id. New ioctl is added to configure boot vcpu id that was assumed to be 0 till now. Signed-off-by: Gleb Natapov <gleb@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
Gleb Natapov · Avi Kivity
1 parent 1ed0ce000a
Showing 9 changed files with 55 additions and 33 deletions Side-by-side Diff
arch/ia64/include/asm/kvm_host.h
arch/ia64/kvm/Kconfig
arch/ia64/kvm/kvm-ia64.c
arch/ia64/kvm/vcpu.c
arch/x86/kvm/Kconfig
include/linux/kvm.h
include/linux/kvm_host.h
virt/kvm/Kconfig
virt/kvm/kvm_main.c
@@ -465,7 +465,6 @@
 	unsigned long	metaphysical_rr4;
 	unsigned long	vmm_init_rr;
  
-	int		online_vcpus;
 	int		is_sn2;
  
 	struct kvm_ioapic *vioapic;
@@ -25,6 +25,7 @@
 	select PREEMPT_NOTIFIERS
 	select ANON_INODES
 	select HAVE_KVM_IRQCHIP
+	select KVM_APIC_ARCHITECTURE
 	---help---
 	  Support hosting fully virtualized guest machines using hardware
 	  virtualization extensions.  You will need a fairly recent
@@ -338,7 +338,7 @@
 	union ia64_lid lid;
 	int i;
  
-	for (i = 0; i < kvm->arch.online_vcpus; i++) {
+	for (i = 0; i < atomic_read(&kvm->online_vcpus); i++) {
 		if (kvm->vcpus[i]) {
 			lid.val = VCPU_LID(kvm->vcpus[i]);
 			if (lid.id == id && lid.eid == eid)
@@ -412,7 +412,7 @@
  
 	call_data.ptc_g_data = p->u.ptc_g_data;
  
-	for (i = 0; i < kvm->arch.online_vcpus; i++) {
+	for (i = 0; i < atomic_read(&kvm->online_vcpus); i++) {
 		if (!kvm->vcpus[i] || kvm->vcpus[i]->arch.mp_state ==
 						KVM_MP_STATE_UNINITIALIZED ||
 					vcpu == kvm->vcpus[i])
@@ -852,8 +852,6 @@
  
 	kvm_init_vm(kvm);
  
-	kvm->arch.online_vcpus = 0;
-
 	return kvm;
  
 }
@@ -1355,8 +1353,6 @@
 		printk(KERN_DEBUG"kvm: vcpu_setup error!!\n");
 		goto fail;
 	}
-
-	kvm->arch.online_vcpus++;
  
 	return vcpu;
 fail:
@@ -831,7 +831,7 @@
 	kvm = (struct kvm *)KVM_VM_BASE;
  
 	if (kvm_vcpu_is_bsp(vcpu)) {
-		for (i = 0; i < kvm->arch.online_vcpus; i++) {
+		for (i = 0; i < atomic_read(&kvm->online_vcpus); i++) {
 			v = (struct kvm_vcpu *)((char *)vcpu +
 					sizeof(struct kvm_vcpu_data) * i);
 			VMX(v, itc_offset) = itc_offset;
@@ -27,6 +27,7 @@
 	select ANON_INODES
 	select HAVE_KVM_IRQCHIP
 	select HAVE_KVM_EVENTFD
+	select KVM_APIC_ARCHITECTURE
 	---help---
 	  Support hosting fully virtualized guest machines using hardware
 	  virtualization extensions.  You will need a fairly recent
@@ -430,6 +430,7 @@
 #ifdef __KVM_HAVE_PIT
 #define KVM_CAP_PIT2 33
 #endif
+#define KVM_CAP_SET_BOOT_CPU_ID 34
  
 #ifdef KVM_CAP_IRQ_ROUTING
  
@@ -537,6 +538,7 @@
 #define KVM_DEASSIGN_DEV_IRQ       _IOW(KVMIO, 0x75, struct kvm_assigned_irq)
 #define KVM_IRQFD                  _IOW(KVMIO, 0x76, struct kvm_irqfd)
 #define KVM_CREATE_PIT2		   _IOW(KVMIO, 0x77, struct kvm_pit_config)
+#define KVM_SET_BOOT_CPU_ID        _IO(KVMIO, 0x78)
  
 /*
  * ioctls for vcpu fds
@@ -131,8 +131,12 @@
 	int nmemslots;
 	struct kvm_memory_slot memslots[KVM_MEMORY_SLOTS +
 					KVM_PRIVATE_MEM_SLOTS];
+#ifdef CONFIG_KVM_APIC_ARCHITECTURE
+	u32 bsp_vcpu_id;
 	struct kvm_vcpu *bsp_vcpu;
+#endif
 	struct kvm_vcpu *vcpus[KVM_MAX_VCPUS];
+	atomic_t online_vcpus;
 	struct list_head vm_list;
 	struct mutex lock;
 	struct kvm_io_bus mmio_bus;
  
@@ -550,9 +554,11 @@
  
 #endif /* CONFIG_HAVE_KVM_EVENTFD */
  
+#ifdef CONFIG_KVM_APIC_ARCHITECTURE
 static inline bool kvm_vcpu_is_bsp(struct kvm_vcpu *vcpu)
 {
 	return vcpu->kvm->bsp_vcpu == vcpu;
 }
+#endif
 #endif
@@ -9,4 +9,7 @@
 config HAVE_KVM_EVENTFD
        bool
        select EVENTFD
+
+config KVM_APIC_ARCHITECTURE
+       bool
@@ -689,11 +689,6 @@
 }
 #endif
  
-static inline int valid_vcpu(int n)
-{
-	return likely(n >= 0 && n < KVM_MAX_VCPUS);
-}
-
 inline int kvm_is_mmio_pfn(pfn_t pfn)
 {
 	if (pfn_valid(pfn)) {
  
  
@@ -1714,24 +1709,18 @@
  */
 static int create_vcpu_fd(struct kvm_vcpu *vcpu)
 {
-	int fd = anon_inode_getfd("kvm-vcpu", &kvm_vcpu_fops, vcpu, 0);
-	if (fd < 0)
-		kvm_put_kvm(vcpu->kvm);
-	return fd;
+	return anon_inode_getfd("kvm-vcpu", &kvm_vcpu_fops, vcpu, 0);
 }
  
 /*
  * Creates some virtual cpus.  Good luck creating more than one.
  */
-static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, int n)
+static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, u32 id)
 {
 	int r;
 	struct kvm_vcpu *vcpu;
  
-	if (!valid_vcpu(n))
-		return -EINVAL;
-
-	vcpu = kvm_arch_vcpu_create(kvm, n);
+	vcpu = kvm_arch_vcpu_create(kvm, id);
 	if (IS_ERR(vcpu))
 		return PTR_ERR(vcpu);
  
  
  
  
  
@@ -1742,25 +1731,38 @@
 		return r;
  
 	mutex_lock(&kvm->lock);
-	if (kvm->vcpus[n]) {
-		r = -EEXIST;
+	if (atomic_read(&kvm->online_vcpus) == KVM_MAX_VCPUS) {
+		r = -EINVAL;
 		goto vcpu_destroy;
 	}
-	kvm->vcpus[n] = vcpu;
-	if (n == 0)
-		kvm->bsp_vcpu = vcpu;
-	mutex_unlock(&kvm->lock);
  
+	for (r = 0; r < atomic_read(&kvm->online_vcpus); r++)
+		if (kvm->vcpus[r]->vcpu_id == id) {
+			r = -EEXIST;
+			goto vcpu_destroy;
+		}
+
+	BUG_ON(kvm->vcpus[atomic_read(&kvm->online_vcpus)]);
+
 	/* Now it's all set up, let userspace reach it */
 	kvm_get_kvm(kvm);
 	r = create_vcpu_fd(vcpu);
-	if (r < 0)
-		goto unlink;
+	if (r < 0) {
+		kvm_put_kvm(kvm);
+		goto vcpu_destroy;
+	}
+
+	kvm->vcpus[atomic_read(&kvm->online_vcpus)] = vcpu;
+	smp_wmb();
+	atomic_inc(&kvm->online_vcpus);
+
+#ifdef CONFIG_KVM_APIC_ARCHITECTURE
+	if (kvm->bsp_vcpu_id == id)
+		kvm->bsp_vcpu = vcpu;
+#endif
+	mutex_unlock(&kvm->lock);
 	return r;
  
-unlink:
-	mutex_lock(&kvm->lock);
-	kvm->vcpus[n] = NULL;
 vcpu_destroy:
 	mutex_unlock(&kvm->lock);
 	kvm_arch_vcpu_destroy(vcpu);
@@ -2233,6 +2235,15 @@
 		r = kvm_irqfd(kvm, data.fd, data.gsi, data.flags);
 		break;
 	}
+#ifdef CONFIG_KVM_APIC_ARCHITECTURE
+	case KVM_SET_BOOT_CPU_ID:
+		r = 0;
+		if (atomic_read(&kvm->online_vcpus) != 0)
+			r = -EBUSY;
+		else
+			kvm->bsp_vcpu_id = arg;
+		break;
+#endif
 	default:
 		r = kvm_arch_vm_ioctl(filp, ioctl, arg);
 	}
@@ -2299,6 +2310,9 @@
 	case KVM_CAP_USER_MEMORY:
 	case KVM_CAP_DESTROY_MEMORY_REGION_WORKS:
 	case KVM_CAP_JOIN_MEMORY_REGIONS_WORKS:
+#ifdef CONFIG_KVM_APIC_ARCHITECTURE
+	case KVM_CAP_SET_BOOT_CPU_ID:
+#endif
 		return 1;
 #ifdef CONFIG_HAVE_KVM_IRQCHIP
 	case KVM_CAP_IRQ_ROUTING:
...	...	@@ -465,7 +465,6 @@
465	465	unsigned long metaphysical_rr4;
466	466	unsigned long vmm_init_rr;
467	467
468		- int online_vcpus;
469	468	int is_sn2;
470	469
471	470	struct kvm_ioapic *vioapic;
...	...	@@ -25,6 +25,7 @@
25	25	select PREEMPT_NOTIFIERS
26	26	select ANON_INODES
27	27	select HAVE_KVM_IRQCHIP
	28	+ select KVM_APIC_ARCHITECTURE
28	29	---help---
29	30	Support hosting fully virtualized guest machines using hardware
30	31	virtualization extensions. You will need a fairly recent
...	...	@@ -338,7 +338,7 @@
338	338	union ia64_lid lid;
339	339	int i;
340	340
341		- for (i = 0; i < kvm->arch.online_vcpus; i++) {
	341	+ for (i = 0; i < atomic_read(&kvm->online_vcpus); i++) {
342	342	if (kvm->vcpus[i]) {
343	343	lid.val = VCPU_LID(kvm->vcpus[i]);
344	344	if (lid.id == id && lid.eid == eid)
...	...	@@ -412,7 +412,7 @@
412	412
413	413	call_data.ptc_g_data = p->u.ptc_g_data;
414	414
415		- for (i = 0; i < kvm->arch.online_vcpus; i++) {
	415	+ for (i = 0; i < atomic_read(&kvm->online_vcpus); i++) {
416	416	if (!kvm->vcpus[i] \|\| kvm->vcpus[i]->arch.mp_state ==
417	417	KVM_MP_STATE_UNINITIALIZED \|\|
418	418	vcpu == kvm->vcpus[i])
...	...	@@ -852,8 +852,6 @@
852	852
853	853	kvm_init_vm(kvm);
854	854
855		- kvm->arch.online_vcpus = 0;
856		-
857	855	return kvm;
858	856
859	857	}
...	...	@@ -1355,8 +1353,6 @@
1355	1353	printk(KERN_DEBUG"kvm: vcpu_setup error!!\n");
1356	1354	goto fail;
1357	1355	}
1358		-
1359		- kvm->arch.online_vcpus++;
1360	1356
1361	1357	return vcpu;
1362	1358	fail:
...	...	@@ -831,7 +831,7 @@
831	831	kvm = (struct kvm *)KVM_VM_BASE;
832	832
833	833	if (kvm_vcpu_is_bsp(vcpu)) {
834		- for (i = 0; i < kvm->arch.online_vcpus; i++) {
	834	+ for (i = 0; i < atomic_read(&kvm->online_vcpus); i++) {
835	835	v = (struct kvm_vcpu )((char )vcpu +
836	836	sizeof(struct kvm_vcpu_data) * i);
837	837	VMX(v, itc_offset) = itc_offset;
...	...	@@ -27,6 +27,7 @@
27	27	select ANON_INODES
28	28	select HAVE_KVM_IRQCHIP
29	29	select HAVE_KVM_EVENTFD
	30	+ select KVM_APIC_ARCHITECTURE
30	31	---help---
31	32	Support hosting fully virtualized guest machines using hardware
32	33	virtualization extensions. You will need a fairly recent
...	...	@@ -430,6 +430,7 @@
430	430	#ifdef __KVM_HAVE_PIT
431	431	#define KVM_CAP_PIT2 33
432	432	#endif
	433	+#define KVM_CAP_SET_BOOT_CPU_ID 34
433	434
434	435	#ifdef KVM_CAP_IRQ_ROUTING
435	436
...	...	@@ -537,6 +538,7 @@
537	538	#define KVM_DEASSIGN_DEV_IRQ _IOW(KVMIO, 0x75, struct kvm_assigned_irq)
538	539	#define KVM_IRQFD _IOW(KVMIO, 0x76, struct kvm_irqfd)
539	540	#define KVM_CREATE_PIT2 _IOW(KVMIO, 0x77, struct kvm_pit_config)
	541	+#define KVM_SET_BOOT_CPU_ID _IO(KVMIO, 0x78)
540	542
541	543	/*
542	544	* ioctls for vcpu fds
...	...	@@ -131,8 +131,12 @@
131	131	int nmemslots;
132	132	struct kvm_memory_slot memslots[KVM_MEMORY_SLOTS +
133	133	KVM_PRIVATE_MEM_SLOTS];
	134	+#ifdef CONFIG_KVM_APIC_ARCHITECTURE
	135	+ u32 bsp_vcpu_id;
134	136	struct kvm_vcpu *bsp_vcpu;
	137	+#endif
135	138	struct kvm_vcpu *vcpus[KVM_MAX_VCPUS];
	139	+ atomic_t online_vcpus;
136	140	struct list_head vm_list;
137	141	struct mutex lock;
138	142	struct kvm_io_bus mmio_bus;
139	143
...	...	@@ -550,9 +554,11 @@
550	554
551	555	#endif /* CONFIG_HAVE_KVM_EVENTFD */
552	556
	557	+#ifdef CONFIG_KVM_APIC_ARCHITECTURE
553	558	static inline bool kvm_vcpu_is_bsp(struct kvm_vcpu *vcpu)
554	559	{
555	560	return vcpu->kvm->bsp_vcpu == vcpu;
556	561	}
	562	+#endif
557	563	#endif
...	...	@@ -9,4 +9,7 @@
9	9	config HAVE_KVM_EVENTFD
10	10	bool
11	11	select EVENTFD
	12	+
	13	+config KVM_APIC_ARCHITECTURE
	14	+ bool
...	...	@@ -689,11 +689,6 @@
689	689	}
690	690	#endif
691	691
692		-static inline int valid_vcpu(int n)
693		-{
694		- return likely(n >= 0 && n < KVM_MAX_VCPUS);
695		-}
696		-
697	692	inline int kvm_is_mmio_pfn(pfn_t pfn)
698	693	{
699	694	if (pfn_valid(pfn)) {
700	695
701	696
...	...	@@ -1714,24 +1709,18 @@
1714	1709	*/
1715	1710	static int create_vcpu_fd(struct kvm_vcpu *vcpu)
1716	1711	{
1717		- int fd = anon_inode_getfd("kvm-vcpu", &kvm_vcpu_fops, vcpu, 0);
1718		- if (fd < 0)
1719		- kvm_put_kvm(vcpu->kvm);
1720		- return fd;
	1712	+ return anon_inode_getfd("kvm-vcpu", &kvm_vcpu_fops, vcpu, 0);
1721	1713	}
1722	1714
1723	1715	/*
1724	1716	* Creates some virtual cpus. Good luck creating more than one.
1725	1717	*/
1726		-static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, int n)
	1718	+static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, u32 id)
1727	1719	{
1728	1720	int r;
1729	1721	struct kvm_vcpu *vcpu;
1730	1722
1731		- if (!valid_vcpu(n))
1732		- return -EINVAL;
1733		-
1734		- vcpu = kvm_arch_vcpu_create(kvm, n);
	1723	+ vcpu = kvm_arch_vcpu_create(kvm, id);
1735	1724	if (IS_ERR(vcpu))
1736	1725	return PTR_ERR(vcpu);
1737	1726
1738	1727
1739	1728
1740	1729
1741	1730
...	...	@@ -1742,25 +1731,38 @@
1742	1731	return r;
1743	1732
1744	1733	mutex_lock(&kvm->lock);
1745		- if (kvm->vcpus[n]) {
1746		- r = -EEXIST;
	1734	+ if (atomic_read(&kvm->online_vcpus) == KVM_MAX_VCPUS) {
	1735	+ r = -EINVAL;
1747	1736	goto vcpu_destroy;
1748	1737	}
1749		- kvm->vcpus[n] = vcpu;
1750		- if (n == 0)
1751		- kvm->bsp_vcpu = vcpu;
1752		- mutex_unlock(&kvm->lock);
1753	1738
	1739	+ for (r = 0; r < atomic_read(&kvm->online_vcpus); r++)
	1740	+ if (kvm->vcpus[r]->vcpu_id == id) {
	1741	+ r = -EEXIST;
	1742	+ goto vcpu_destroy;
	1743	+ }
	1744	+
	1745	+ BUG_ON(kvm->vcpus[atomic_read(&kvm->online_vcpus)]);
	1746	+
1754	1747	/* Now it's all set up, let userspace reach it */
1755	1748	kvm_get_kvm(kvm);
1756	1749	r = create_vcpu_fd(vcpu);
1757		- if (r < 0)
1758		- goto unlink;
	1750	+ if (r < 0) {
	1751	+ kvm_put_kvm(kvm);
	1752	+ goto vcpu_destroy;
	1753	+ }
	1754	+
	1755	+ kvm->vcpus[atomic_read(&kvm->online_vcpus)] = vcpu;
	1756	+ smp_wmb();
	1757	+ atomic_inc(&kvm->online_vcpus);
	1758	+
	1759	+#ifdef CONFIG_KVM_APIC_ARCHITECTURE
	1760	+ if (kvm->bsp_vcpu_id == id)
	1761	+ kvm->bsp_vcpu = vcpu;
	1762	+#endif
	1763	+ mutex_unlock(&kvm->lock);
1759	1764	return r;
1760	1765
1761		-unlink:
1762		- mutex_lock(&kvm->lock);
1763		- kvm->vcpus[n] = NULL;
1764	1766	vcpu_destroy:
1765	1767	mutex_unlock(&kvm->lock);
1766	1768	kvm_arch_vcpu_destroy(vcpu);
...	...	@@ -2233,6 +2235,15 @@
2233	2235	r = kvm_irqfd(kvm, data.fd, data.gsi, data.flags);
2234	2236	break;
2235	2237	}
	2238	+#ifdef CONFIG_KVM_APIC_ARCHITECTURE
	2239	+ case KVM_SET_BOOT_CPU_ID:
	2240	+ r = 0;
	2241	+ if (atomic_read(&kvm->online_vcpus) != 0)
	2242	+ r = -EBUSY;
	2243	+ else
	2244	+ kvm->bsp_vcpu_id = arg;
	2245	+ break;
	2246	+#endif
2236	2247	default:
2237	2248	r = kvm_arch_vm_ioctl(filp, ioctl, arg);
2238	2249	}
...	...	@@ -2299,6 +2310,9 @@
2299	2310	case KVM_CAP_USER_MEMORY:
2300	2311	case KVM_CAP_DESTROY_MEMORY_REGION_WORKS:
2301	2312	case KVM_CAP_JOIN_MEMORY_REGIONS_WORKS:
	2313	+#ifdef CONFIG_KVM_APIC_ARCHITECTURE
	2314	+ case KVM_CAP_SET_BOOT_CPU_ID:
	2315	+#endif
2302	2316	return 1;
2303	2317	#ifdef CONFIG_HAVE_KVM_IRQCHIP
2304	2318	case KVM_CAP_IRQ_ROUTING: