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@xxxxxxx>
---
v1 -> v2:
- add CAP to expose the vm based CHECK_EXTENSION ioctl availability
---
Documentation/virtual/kvm/api.txt | 7 +++--
include/uapi/linux/kvm.h | 1 +
virt/kvm/kvm_main.c | 58 +++++++++++++++++++++------------------
3 files changed, 37 insertions(+), 29 deletions(-)
diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index 6955318..235630c 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -148,9 +148,9 @@ of banks, as set via the KVM_X86_SETUP_MCE ioctl.
4.4 KVM_CHECK_EXTENSION
-Capability: basic
+Capability: basic, KVM_CAP_CHECK_EXTENSION_VM for vm ioctl
Architectures: all
-Type: system ioctl
+Type: system ioctl, vm ioctl
Parameters: extension identifier (KVM_CAP_*)
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
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
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 0418b74..51776ca 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -759,6 +759,7 @@ struct kvm_ppc_smmu_info {
#define KVM_CAP_ARM_PSCI_0_2 102
#define KVM_CAP_PPC_FIXUP_HCALL 103
#define KVM_CAP_PPC_ENABLE_HCALL 104
+#define KVM_CAP_CHECK_EXTENSION_VM 105
#ifdef KVM_CAP_IRQ_ROUTING
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index e28f3ca..1b95cc9 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -2324,6 +2324,34 @@ static int kvm_ioctl_create_device(struct kvm *kvm,
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,
unsigned int ioctl, unsigned long arg)
{
@@ -2487,6 +2515,9 @@ static long kvm_vm_ioctl(struct file *filp,
r = 0;
break;
}
+ case KVM_CHECK_EXTENSION:
+ r = kvm_vm_ioctl_check_extension_generic(kvm, arg);
+ break;
default:
r = kvm_arch_vm_ioctl(filp, ioctl, arg);
if (r == -ENOTTY)
@@ -2571,33 +2602,6 @@ static int kvm_dev_ioctl_create_vm(unsigned long type)
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,
unsigned int ioctl, unsigned long arg)
{
--
1.8.1.4
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