KVM: Don't pre-reserve xarray entries when storing empty/NULL attributesgrafted

Skip the xarray reservation loop when clearing all memory attributes, as
storing NULL only erases the entry and never needs to allocate, so no
reservation (and no cleanup of a failed one) is required in that case.

Suggested-by: Sean Christopherson <seanjc@google.com>
Cc: David Ballesteros <davimaba.v@proton.me>
Signed-off-by: Zeng Chi <zengchi@kylinos.cn>
Link: https://patch.msgid.link/20260921102442.1232375-1-zeng_chi911@163.com
[sean: split to separate patch]
Signed-off-by: Sean Christopherson <seanjc@google.com>

1 files changed, 107 insertions, 0 deletions

diff --git a/Documentation/driver-api/infrastructure.rst b/Documentation/driver-api/infrastructure.rst
new file mode 100644
index 000000000..ac73e60fb
--- /dev/null
+++ b/Documentation/driver-api/infrastructure.rst
@@ -0,0 +1,107 @@
+Device drivers infrastructure
+=============================
+
+The Basic Device Driver-Model Structures
+----------------------------------------
+
+.. kernel-doc:: include/linux/device.h
+   :internal:
+   :no-identifiers: device_link_state
+
+.. kernel-doc:: include/linux/device/bus.h
+   :identifiers: bus_type bus_notifier_event
+
+.. kernel-doc:: include/linux/device/class.h
+   :identifiers: class
+
+.. kernel-doc:: include/linux/device/driver.h
+   :identifiers: probe_type device_driver
+
+.. kernel-doc:: include/linux/property.h
+
+.. kernel-doc:: include/linux/fwnode.h
+
+Device Drivers Base
+-------------------
+
+.. kernel-doc:: drivers/base/init.c
+   :internal:
+
+.. kernel-doc:: include/linux/device/driver.h
+   :no-identifiers: probe_type device_driver
+
+.. kernel-doc:: drivers/base/driver.c
+   :export:
+
+.. kernel-doc:: drivers/base/core.c
+   :export:
+
+.. kernel-doc:: drivers/base/syscore.c
+   :export:
+
+.. kernel-doc:: include/linux/device/class.h
+   :no-identifiers: class
+
+.. kernel-doc:: drivers/base/class.c
+   :export:
+
+.. kernel-doc:: include/linux/device/faux.h
+   :internal:
+
+.. kernel-doc:: drivers/base/faux.c
+   :export:
+
+.. kernel-doc:: drivers/base/node.c
+   :internal:
+
+.. kernel-doc:: drivers/base/transport_class.c
+   :export:
+
+.. kernel-doc:: drivers/base/dd.c
+   :export:
+
+.. kernel-doc:: include/linux/platform_device.h
+   :internal:
+
+.. kernel-doc:: drivers/base/platform.c
+   :export:
+
+.. kernel-doc:: include/linux/device/bus.h
+   :no-identifiers: bus_type bus_notifier_event
+
+.. kernel-doc:: drivers/base/bus.c
+   :export:
+
+Device Drivers DMA Management
+-----------------------------
+
+.. kernel-doc:: kernel/dma/mapping.c
+   :export:
+
+Device drivers PnP support
+--------------------------
+
+.. kernel-doc:: drivers/pnp/core.c
+   :internal:
+
+.. kernel-doc:: drivers/pnp/card.c
+   :export:
+
+.. kernel-doc:: drivers/pnp/driver.c
+   :internal:
+
+.. kernel-doc:: drivers/pnp/manager.c
+   :export:
+
+.. kernel-doc:: drivers/pnp/support.c
+   :export:
+
+Userspace IO devices
+--------------------
+
+.. kernel-doc:: drivers/uio/uio.c
+   :export:
+
+.. kernel-doc:: include/linux/uio_driver.h
+   :internal:
+