If this CAP returns true, then guestmem_hugetlb can be used as a
custom allocator for guest_memfd.

Change-Id: I4edef395b5bd5814b70c81788d87aa94823c35d5
Signed-off-by: Ackerley Tng <ackerleytng@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 af486b2e4862..5012343dc2c5 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -932,6 +932,7 @@ struct kvm_enable_cap {
 #define KVM_CAP_ARM_WRITABLE_IMP_ID_REGS 239
 #define KVM_CAP_GMEM_SHARED_MEM 240
 #define KVM_CAP_GMEM_CONVERSION 241
+#define KVM_CAP_GMEM_HUGETLB 242
 
 struct kvm_irq_routing_irqchip {
 	__u32 irqchip;
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 92054b1bbd3f..230bcb853712 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -4845,6 +4845,10 @@ static int kvm_vm_ioctl_check_extension_generic(struct kvm *kvm, long arg)
 	case KVM_CAP_GMEM_SHARED_MEM:
 	case KVM_CAP_GMEM_CONVERSION:
 		return true;
+#endif
+#ifdef CONFIG_KVM_GMEM_HUGETLB
+	case KVM_CAP_GMEM_HUGETLB:
+		return true;
 #endif
 	default:
 		break;
-- 
2.49.0.1045.g170613ef41-goog