Add the KVM capability KVM_CAP_GMEM_SHARED_MEM, which indicates
that the VM supports shared memory in guest_memfd, or that the
host can create VMs that support shared memory. Supporting shared
memory implies that memory can be mapped when shared with the
host.
Signed-off-by: Fuad Tabba <tabba@xxxxxxxxxx>
---
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 45e6d8fca9b9..117937a895da 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -929,6 +929,7 @@ 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_GMEM_SHARED_MEM 239
struct kvm_irq_routing_irqchip {
__u32 irqchip;
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index ba0327e2d0d3..38f0f402ea46 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -4830,6 +4830,10 @@ 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_KVM_GMEM_SHARED_MEM
+ case KVM_CAP_GMEM_SHARED_MEM:
+ return !kvm || kvm_arch_gmem_supports_shared_mem(kvm);
#endif
default:
break;
--
2.48.1.502.g6dc24dfdaf-goog
