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/usb/linux-cdc-acm.inf b/Documentation/usb/linux-cdc-acm.inf
new file mode 100644
index 000000000..f0ffc27d4
--- /dev/null
+++ b/Documentation/usb/linux-cdc-acm.inf
@@ -0,0 +1,107 @@
+; Windows USB CDC ACM Setup File
+
+; Based on INF template which was:
+;     Copyright (c) 2000 Microsoft Corporation
+;     Copyright (c) 2007 Microchip Technology Inc.
+; likely to be covered by the MLPL as found at:
+;    <http://msdn.microsoft.com/en-us/cc300389.aspx#MLPL>.
+; For use only on Windows operating systems.
+
+[Version]
+Signature="$Windows NT$"
+Class=Ports
+ClassGuid={4D36E978-E325-11CE-BFC1-08002BE10318}
+Provider=%Linux%
+DriverVer=11/15/2007,5.1.2600.0
+
+[Manufacturer]
+%Linux%=DeviceList, NTamd64
+
+[DestinationDirs]
+DefaultDestDir=12
+
+
+;------------------------------------------------------------------------------
+;  Windows 2000/XP/Vista-32bit Sections
+;------------------------------------------------------------------------------
+
+[DriverInstall.nt]
+include=mdmcpq.inf
+CopyFiles=DriverCopyFiles.nt
+AddReg=DriverInstall.nt.AddReg
+
+[DriverCopyFiles.nt]
+usbser.sys,,,0x20
+
+[DriverInstall.nt.AddReg]
+HKR,,DevLoader,,*ntkern
+HKR,,NTMPDriver,,USBSER.sys
+HKR,,EnumPropPages32,,"MsPorts.dll,SerialPortPropPageProvider"
+
+[DriverInstall.nt.Services]
+AddService=usbser, 0x00000002, DriverService.nt
+
+[DriverService.nt]
+DisplayName=%SERVICE%
+ServiceType=1
+StartType=3
+ErrorControl=1
+ServiceBinary=%12%\USBSER.sys
+
+;------------------------------------------------------------------------------
+;  Vista-64bit Sections
+;------------------------------------------------------------------------------
+
+[DriverInstall.NTamd64]
+include=mdmcpq.inf
+CopyFiles=DriverCopyFiles.NTamd64
+AddReg=DriverInstall.NTamd64.AddReg
+
+[DriverCopyFiles.NTamd64]
+USBSER.sys,,,0x20
+
+[DriverInstall.NTamd64.AddReg]
+HKR,,DevLoader,,*ntkern
+HKR,,NTMPDriver,,USBSER.sys
+HKR,,EnumPropPages32,,"MsPorts.dll,SerialPortPropPageProvider"
+
+[DriverInstall.NTamd64.Services]
+AddService=usbser, 0x00000002, DriverService.NTamd64
+
+[DriverService.NTamd64]
+DisplayName=%SERVICE%
+ServiceType=1
+StartType=3
+ErrorControl=1
+ServiceBinary=%12%\USBSER.sys
+
+
+;------------------------------------------------------------------------------
+;  Vendor and Product ID Definitions
+;------------------------------------------------------------------------------
+; When developing your USB device, the VID and PID used in the PC side
+; application program and the firmware on the microcontroller must match.
+; Modify the below line to use your VID and PID.  Use the format as shown
+; below.
+; Note: One INF file can be used for multiple devices with different
+;       VID and PIDs.  For each supported device, append
+;       ",USB\VID_xxxx&PID_yyyy" to the end of the line.
+;------------------------------------------------------------------------------
+[SourceDisksFiles]
+[SourceDisksNames]
+[DeviceList]
+%DESCRIPTION%=DriverInstall, USB\VID_0525&PID_A4A7, USB\VID_1D6B&PID_0104&MI_02, USB\VID_1D6B&PID_0106&MI_00
+
+[DeviceList.NTamd64]
+%DESCRIPTION%=DriverInstall, USB\VID_0525&PID_A4A7, USB\VID_1D6B&PID_0104&MI_02, USB\VID_1D6B&PID_0106&MI_00
+
+
+;------------------------------------------------------------------------------
+;  String Definitions
+;------------------------------------------------------------------------------
+;Modify these strings to customize your device
+;------------------------------------------------------------------------------
+[Strings]
+Linux               = "Linux Developer Community"
+DESCRIPTION         = "Gadget Serial"
+SERVICE             = "USB RS-232 Emulation Driver"