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, 19 insertions, 0 deletions

diff --git a/Documentation/accel/rocket/index.rst b/Documentation/accel/rocket/index.rst
new file mode 100644
index 000000000..70f97bccf
--- /dev/null
+++ b/Documentation/accel/rocket/index.rst
@@ -0,0 +1,19 @@
+.. SPDX-License-Identifier: GPL-2.0-only
+
+=====================================
+ accel/rocket Rockchip NPU driver
+=====================================
+
+The accel/rocket driver supports the Neural Processing Units (NPUs) inside some
+Rockchip SoCs such as the RK3588. Rockchip calls it RKNN and sometimes RKNPU.
+
+The hardware is described in chapter 36 in the RK3588 TRM.
+
+This driver just powers the hardware on and off, allocates and maps buffers to
+the device and submits jobs to the frontend unit. Everything else is done in
+userspace, as a Gallium driver (also called rocket) that is part of the Mesa3D
+project.
+
+Hardware currently supported:
+
+* RK3588