Hi Fuad,
On 5/14/25 2:34 AM, Fuad Tabba wrote:
This patch enables support for shared memory in guest_memfd, including
mapping that memory at the host userspace. This support is gated by the
configuration option KVM_GMEM_SHARED_MEM, and toggled by the guest_memfd
flag GUEST_MEMFD_FLAG_SUPPORT_SHARED, which can be set when creating a
guest_memfd instance.
Co-developed-by: Ackerley Tng <ackerleytng@xxxxxxxxxx>
Signed-off-by: Ackerley Tng <ackerleytng@xxxxxxxxxx>
Signed-off-by: Fuad Tabba <tabba@xxxxxxxxxx>
---
arch/x86/include/asm/kvm_host.h | 10 ++++
include/linux/kvm_host.h | 13 +++++
include/uapi/linux/kvm.h | 1 +
virt/kvm/Kconfig | 5 ++
virt/kvm/guest_memfd.c | 88 +++++++++++++++++++++++++++++++++
5 files changed, 117 insertions(+)
[...]
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index b6ae8ad8934b..9857022a0f0c 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -1566,6 +1566,7 @@ struct kvm_memory_attributes {
#define KVM_MEMORY_ATTRIBUTE_PRIVATE (1ULL << 3)
#define KVM_CREATE_GUEST_MEMFD _IOWR(KVMIO, 0xd4, struct kvm_create_guest_memfd)
+#define GUEST_MEMFD_FLAG_SUPPORT_SHARED (1UL << 0)
This would be (1ULL << 0) to be consistent with '__u64 struct kvm_create_guest_memfd::flags'
Thanks,
Gavin
