KVM: Allow KVM_CHECK_EXTENSION on the vm fd

The KVM_CHECK_EXTENSION is only available on the kvm fd today. Unfortunately on PPC some of the capabilities change depending on the way a VM was created. So instead we need a way to expose capabilities as VM ioctl, so that we can see which VM type we're using (HV or PR). To enable this, add the KVM_CHECK_EXTENSION ioctl to our vm ioctl portfolio.

Alexander Graf committed 12 years ago

Commit 92b591a1 parent 784aa3d3 files · +37 −29Browse files

Unified · Split

3 files

Documentation/virtual/kvm/api.txt +5 −2
include/uapi/linux/kvm.h +1 −0
virt/kvm/kvm_main.c +31 −27

Documentation/virtual/kvm/api.txt+5−2

@@ -148,9 +148,9 @@ of banks, as set via the KVM_X86_SETUP_MCE ioctl. · 147 unmodified lines
148	148
149	149	4.4 KVM_CHECK_EXTENSION
150	150
151		−Capability: basic
	151	+Capability: basic, KVM_CAP_CHECK_EXTENSION_VM for vm ioctl
152	152	Architectures: all
153		−Type: system ioctl
	153	+Type: system ioctl, vm ioctl
154	154	Parameters: extension identifier (KVM_CAP_*)
155	155	Returns: 0 if unsupported; 1 (or some other positive integer) if supported
156	156
@@ -160,6 +160,9 @@ receives an integer that describes the extension availability. · 3 unmodified lines
160	160	Generally 0 means no and 1 means yes, but some extensions may report
161	161	additional information in the integer return value.
162	162
	163	+Based on their initialization different VMs may have different capabilities.
	164	+It is thus encouraged to use the vm ioctl to query for capabilities (available
	165	+with KVM_CAP_CHECK_EXTENSION_VM on the vm fd)
163	166
164	167	4.5 KVM_GET_VCPU_MMAP_SIZE
165	168

include/uapi/linux/kvm.h+1−0

@@ -759,6 +759,7 @@ struct kvm_ppc_smmu_info { · 758 unmodified lines
759	759	#define KVM_CAP_ARM_PSCI_0_2 102
760	760	#define KVM_CAP_PPC_FIXUP_HCALL 103
761	761	#define KVM_CAP_PPC_ENABLE_HCALL 104
	762	+#define KVM_CAP_CHECK_EXTENSION_VM 105
762	763
763	764	#ifdef KVM_CAP_IRQ_ROUTING
764	765

virt/kvm/kvm_main.c+31−27

@@ -2324,6 +2324,34 @@ static int kvm_ioctl_create_device(struct kvm *kvm, · 2323 unmodified lines
2324	2324	return 0;
2325	2325	}
2326	2326
	2327	+static long kvm_vm_ioctl_check_extension_generic(struct kvm *kvm, long arg)
	2328	+{
	2329	+ switch (arg) {
	2330	+ case KVM_CAP_USER_MEMORY:
	2331	+ case KVM_CAP_DESTROY_MEMORY_REGION_WORKS:
	2332	+ case KVM_CAP_JOIN_MEMORY_REGIONS_WORKS:
	2333	+#ifdef CONFIG_KVM_APIC_ARCHITECTURE
	2334	+ case KVM_CAP_SET_BOOT_CPU_ID:
	2335	+#endif
	2336	+ case KVM_CAP_INTERNAL_ERROR_DATA:
	2337	+#ifdef CONFIG_HAVE_KVM_MSI
	2338	+ case KVM_CAP_SIGNAL_MSI:
	2339	+#endif
	2340	+#ifdef CONFIG_HAVE_KVM_IRQ_ROUTING
	2341	+ case KVM_CAP_IRQFD_RESAMPLE:
	2342	+#endif
	2343	+ case KVM_CAP_CHECK_EXTENSION_VM:
	2344	+ return 1;
	2345	+#ifdef CONFIG_HAVE_KVM_IRQ_ROUTING
	2346	+ case KVM_CAP_IRQ_ROUTING:
	2347	+ return KVM_MAX_IRQ_ROUTES;
	2348	+#endif
	2349	+ default:
	2350	+ break;
	2351	+ }
	2352	+ return kvm_vm_ioctl_check_extension(kvm, arg);
	2353	+}
	2354	+
2327	2355	static long kvm_vm_ioctl(struct file *filp,
2328	2356	unsigned int ioctl, unsigned long arg)
2329	2357	{
@@ -2487,6 +2515,9 @@ static long kvm_vm_ioctl(struct file *filp, · 157 unmodified lines
2487	2515	r = 0;
2488	2516	break;
2489	2517	}
	2518	+ case KVM_CHECK_EXTENSION:
	2519	+ r = kvm_vm_ioctl_check_extension_generic(kvm, arg);
	2520	+ break;
2490	2521	default:
2491	2522	r = kvm_arch_vm_ioctl(filp, ioctl, arg);
2492	2523	if (r == -ENOTTY)
@@ -2571,33 +2602,6 @@ static int kvm_dev_ioctl_create_vm(unsigned long type) · 78 unmodified lines
2571	2602	return r;
2572	2603	}
2573	2604
2574		−static long kvm_vm_ioctl_check_extension_generic(struct kvm *kvm, long arg)
2575		−{
2576		− switch (arg) {
2577		− case KVM_CAP_USER_MEMORY:
2578		− case KVM_CAP_DESTROY_MEMORY_REGION_WORKS:
2579		− case KVM_CAP_JOIN_MEMORY_REGIONS_WORKS:
2580		−#ifdef CONFIG_KVM_APIC_ARCHITECTURE
2581		− case KVM_CAP_SET_BOOT_CPU_ID:
2582		−#endif
2583		− case KVM_CAP_INTERNAL_ERROR_DATA:
2584		−#ifdef CONFIG_HAVE_KVM_MSI
2585		− case KVM_CAP_SIGNAL_MSI:
2586		−#endif
2587		−#ifdef CONFIG_HAVE_KVM_IRQ_ROUTING
2588		− case KVM_CAP_IRQFD_RESAMPLE:
2589		−#endif
2590		− return 1;
2591		−#ifdef CONFIG_HAVE_KVM_IRQ_ROUTING
2592		− case KVM_CAP_IRQ_ROUTING:
2593		− return KVM_MAX_IRQ_ROUTES;
2594		−#endif
2595		− default:
2596		− break;
2597		− }
2598		− return kvm_vm_ioctl_check_extension(kvm, arg);
2599		−}
2600		−
2601	2605	static long kvm_dev_ioctl(struct file *filp,
2602	2606	unsigned int ioctl, unsigned long arg)
2603	2607	{