[PATCH v1 04/13] KVM: Advertise KVM_CAP_USERFAULT in KVM_CHECK_EXTENSION

James Houghton
2024-12-04T19:14:19Z

Advertise support for KVM_CAP_USERFAULT when kvm_has_userfault() returns
true. Currently this is merely IS_ENABLED(CONFIG_HAVE_KVM_USERFAULT), so
it is somewhat redundant.

Signed-off-by: James Houghton <jthoughton@google.com>
---
include/uapi/linux/kvm.h | 1 +
virt/kvm/kvm_main.c | 4 ++++
2 files changed, 5 insertions(+)

diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 641a2e580441..d9a135c895d7 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -936,6 +936,7 @@ struct kvm_enable_cap {
#define KVM_CAP_PRE_FAULT_MEMORY 236
#define KVM_CAP_X86_APIC_BUS_CYCLES_NS 237
#define KVM_CAP_X86_GUEST_MODE 238
+#define KVM_CAP_USERFAULT 239

struct kvm_irq_routing_irqchip {
__u32 irqchip;
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index fa851704db94..b552cdef2850 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -4804,6 +4804,10 @@ static int kvm_vm_ioctl_check_extension_generic(struct kvm *kvm, long arg)
#ifdef CONFIG_KVM_PRIVATE_MEM
case KVM_CAP_GUEST_MEMFD:
return !kvm || kvm_arch_has_private_mem(kvm);
+#endif
+#ifdef CONFIG_HAVE_KVM_USERFAULT
+ case KVM_CAP_USERFAULT:
+ return kvm_has_userfault(kvm);
#endif
default:
break;
--
2.47.0.338.g60cca15819-goog