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authorZeng Chi <zengchi@kylinos.cn>2026-09-21 18:24:42 +0800
committerSean Christopherson <seanjc@google.com>2026-09-22 08:36:16 -0700
commit119e9db233ad0f4cbd4cfb9f9385a7bca378b37d (patch)
tree660d50d4139cb750fbde1ae3432452c20726c99d /Documentation/ABI/testing/sysfs-driver-pciback
downloadlinux-stable-119e9db233ad0f4cbd4cfb9f9385a7bca378b37d.tar.gz
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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>
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+What: /sys/bus/pci/drivers/pciback/quirks
+Date: Oct 2011
+KernelVersion: 3.1
+Contact: xen-devel@lists.xenproject.org
+Description:
+ If the permissive attribute is set, then writing a string in
+ the format of DDDD:BB:DD.F-REG:SIZE:MASK will allow the guest
+ to write and read from the PCI device. That is Domain:Bus:
+ Device.Function-Register:Size:Mask (Domain is optional).
+ For example::
+
+ #echo 00:19.0-E0:2:FF > /sys/bus/pci/drivers/pciback/quirks
+
+ will allow the guest to read and write to the configuration
+ register 0x0E.
+
+What: /sys/bus/pci/drivers/pciback/allow_interrupt_control
+Date: Jan 2020
+KernelVersion: 5.6
+Contact: xen-devel@lists.xenproject.org
+Description:
+ List of devices which can have interrupt control flag (INTx,
+ MSI, MSI-X) set by a connected guest. It is meant to be set
+ only when the guest is a stubdomain hosting device model (qemu)
+ and the actual device is assigned to a HVM. It is not safe
+ (similar to permissive attribute) to set for a devices assigned
+ to a PV guest. The device is automatically removed from this
+ list when the connected pcifront terminates.