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authorAckerley Tng <ackerleytng@google.com>2025-10-16 10:28:44 -0700
committerSean Christopherson <seanjc@google.com>2025-10-20 06:30:40 -0700
commita63ca4236e6799cf4343f9aec9d92afdfa582446 (patch)
treeec964e86b5dc2b1901ab0b64904819bf29a3f8e2 /include
parent392dd9d9488a8a81c2d58f9f4eee99c5b7b8e1c7 (diff)
KVM: guest_memfd: Use guest mem inodes instead of anonymous inodes
guest_memfd's inode represents memory the guest_memfd is providing. guest_memfd's file represents a struct kvm's view of that memory. Using a custom inode allows customization of the inode teardown process via callbacks. For example, ->evict_inode() allows customization of the truncation process on file close, and ->destroy_inode() and ->free_inode() allow customization of the inode freeing process. Customizing the truncation process allows flexibility in management of guest_memfd memory and customization of the inode freeing process allows proper cleanup of memory metadata stored on the inode. Memory metadata is more appropriately stored on the inode (as opposed to the file), since the metadata is for the memory and is not unique to a specific binding and struct kvm. Acked-by: David Hildenbrand <david@redhat.com> Co-developed-by: Fuad Tabba <tabba@google.com> Signed-off-by: Fuad Tabba <tabba@google.com> Signed-off-by: Ackerley Tng <ackerleytng@google.com> Signed-off-by: Shivank Garg <shivankg@amd.com> Tested-by: Ashish Kalra <ashish.kalra@amd.com> [sean: drop helpers, open code logic in __kvm_gmem_create()] Link: https://lore.kernel.org/r/20251016172853.52451-4-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
Diffstat (limited to 'include')
-rw-r--r--include/uapi/linux/magic.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/include/uapi/linux/magic.h b/include/uapi/linux/magic.h
index bb575f3ab45e..638ca21b7a90 100644
--- a/include/uapi/linux/magic.h
+++ b/include/uapi/linux/magic.h
@@ -103,5 +103,6 @@
#define DEVMEM_MAGIC 0x454d444d /* "DMEM" */
#define SECRETMEM_MAGIC 0x5345434d /* "SECM" */
#define PID_FS_MAGIC 0x50494446 /* "PIDF" */
+#define GUEST_MEMFD_MAGIC 0x474d454d /* "GMEM" */
#endif /* __LINUX_MAGIC_H__ */