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KVM: Allow KVM_CHECK_EXTENSION on the vm fd

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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.

Signed-off-by: Alexander Graf <agraf@suse.de>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Alexander Graf 2014-07-14 18:33:08 +02:00
commit 92b591a4c4
3 changed files with 37 additions and 29 deletions
Download patch file Download diff file Expand all files Collapse all files

7
Documentation/virtual/kvm/api.txt
View file

@ -148,9 +148,9 @@ of banks, as set via the KVM_X86_SETUP_MCE ioctl.
4.4 KVM_CHECK_EXTENSION 4.4 KVM_CHECK_EXTENSION
Capability: basic Capability: basic, KVM_CAP_CHECK_EXTENSION_VM for vm ioctl
Architectures: all Architectures: all
Type: system ioctl Type: system ioctl, vm ioctl
Parameters: extension identifier (KVM_CAP_*) Parameters: extension identifier (KVM_CAP_*)
Returns: 0 if unsupported; 1 (or some other positive integer) if supported Returns: 0 if unsupported; 1 (or some other positive integer) if supported
@ -160,6 +160,9 @@ receives an integer that describes the extension availability.
Generally 0 means no and 1 means yes, but some extensions may report Generally 0 means no and 1 means yes, but some extensions may report
additional information in the integer return value. additional information in the integer return value.
Based on their initialization different VMs may have different capabilities.
It is thus encouraged to use the vm ioctl to query for capabilities (available
with KVM_CAP_CHECK_EXTENSION_VM on the vm fd)
4.5 KVM_GET_VCPU_MMAP_SIZE 4.5 KVM_GET_VCPU_MMAP_SIZE

1
include/uapi/linux/kvm.h
View file

@ -759,6 +759,7 @@ struct kvm_ppc_smmu_info {
#define KVM_CAP_ARM_PSCI_0_2 102 #define KVM_CAP_ARM_PSCI_0_2 102
#define KVM_CAP_PPC_FIXUP_HCALL 103 #define KVM_CAP_PPC_FIXUP_HCALL 103
#define KVM_CAP_PPC_ENABLE_HCALL 104 #define KVM_CAP_PPC_ENABLE_HCALL 104
#define KVM_CAP_CHECK_EXTENSION_VM 105
#ifdef KVM_CAP_IRQ_ROUTING #ifdef KVM_CAP_IRQ_ROUTING

58
virt/kvm/kvm_main.c
View file

@ -2324,6 +2324,34 @@ static int kvm_ioctl_create_device(struct kvm *kvm,
return 0; return 0;
} }
static long kvm_vm_ioctl_check_extension_generic(struct kvm *kvm, long arg)
{
switch (arg) {
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
case KVM_CAP_INTERNAL_ERROR_DATA:
#ifdef CONFIG_HAVE_KVM_MSI
case KVM_CAP_SIGNAL_MSI:
#endif
#ifdef CONFIG_HAVE_KVM_IRQ_ROUTING
case KVM_CAP_IRQFD_RESAMPLE:
#endif
case KVM_CAP_CHECK_EXTENSION_VM:
return 1;
#ifdef CONFIG_HAVE_KVM_IRQ_ROUTING
case KVM_CAP_IRQ_ROUTING:
return KVM_MAX_IRQ_ROUTES;
#endif
default:
break;
}
return kvm_vm_ioctl_check_extension(kvm, arg);
}
static long kvm_vm_ioctl(struct file *filp, static long kvm_vm_ioctl(struct file *filp,
unsigned int ioctl, unsigned long arg) unsigned int ioctl, unsigned long arg)
{ {
@ -2487,6 +2515,9 @@ static long kvm_vm_ioctl(struct file *filp,
r = 0; r = 0;
break; break;
} }
case KVM_CHECK_EXTENSION:
r = kvm_vm_ioctl_check_extension_generic(kvm, arg);
break;
default: default:
r = kvm_arch_vm_ioctl(filp, ioctl, arg); r = kvm_arch_vm_ioctl(filp, ioctl, arg);
if (r == -ENOTTY) if (r == -ENOTTY)
@ -2571,33 +2602,6 @@ static int kvm_dev_ioctl_create_vm(unsigned long type)
return r; return r;
} }
static long kvm_vm_ioctl_check_extension_generic(struct kvm *kvm, long arg)
{
switch (arg) {
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
case KVM_CAP_INTERNAL_ERROR_DATA:
#ifdef CONFIG_HAVE_KVM_MSI
case KVM_CAP_SIGNAL_MSI:
#endif
#ifdef CONFIG_HAVE_KVM_IRQ_ROUTING
case KVM_CAP_IRQFD_RESAMPLE:
#endif
return 1;
#ifdef CONFIG_HAVE_KVM_IRQ_ROUTING
case KVM_CAP_IRQ_ROUTING:
return KVM_MAX_IRQ_ROUTES;
#endif
default:
break;
}
return kvm_vm_ioctl_check_extension(kvm, arg);
}
static long kvm_dev_ioctl(struct file *filp, static long kvm_dev_ioctl(struct file *filp,
unsigned int ioctl, unsigned long arg) unsigned int ioctl, unsigned long arg)
{ {