From 119e9db233ad0f4cbd4cfb9f9385a7bca378b37d Mon Sep 17 00:00:00 2001 From: Zeng Chi Date: Mon, 21 Sep 2026 18:24:42 +0800 Subject: KVM: Don't pre-reserve xarray entries when storing empty/NULL attributes 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 Cc: David Ballesteros Signed-off-by: Zeng Chi Link: https://patch.msgid.link/20260921102442.1232375-1-zeng_chi911@163.com [sean: split to separate patch] Signed-off-by: Sean Christopherson --- Documentation/ABI/testing/sysfs-driver-ppi | 75 ++++++++++++++++++++++++++++++ 1 file changed, 75 insertions(+) create mode 100644 Documentation/ABI/testing/sysfs-driver-ppi (limited to 'Documentation/ABI/testing/sysfs-driver-ppi') diff --git a/Documentation/ABI/testing/sysfs-driver-ppi b/Documentation/ABI/testing/sysfs-driver-ppi new file mode 100644 index 000000000..1a56fc507 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-driver-ppi @@ -0,0 +1,75 @@ +What: /sys/class/tpm/tpmX/ppi/ +Date: August 2012 +KernelVersion: 3.6 +Contact: xiaoyan.zhang@intel.com +Description: + This folder includes the attributes related with PPI (Physical + Presence Interface). Only if TPM is supported by BIOS, this + folder makes sense. The folder path can be got by command + 'find /sys/ -name 'pcrs''. For the detail information of PPI, + please refer to the PPI specification from + + http://www.trustedcomputinggroup.org/ + + In Linux 4.2 ppi was moved to the character device directory. + A symlink from tpmX/device/ppi to tpmX/ppi to provide backwards + compatibility. + +What: /sys/class/tpm/tpmX/ppi/version +Date: August 2012 +Contact: xiaoyan.zhang@intel.com +Description: + This attribute shows the version of the PPI supported by the + platform. + This file is readonly. + +What: /sys/class/tpm/tpmX/ppi/request +Date: August 2012 +Contact: xiaoyan.zhang@intel.com +Description: + This attribute shows the request for an operation to be + executed in the pre-OS environment. It is the only input from + the OS to the pre-OS environment. The request should be an + integer value range from 1 to 160, and 0 means no request. + This file can be read and written. + +What: /sys/class/tpm/tpmX/ppi/response +Date: August 2012 +Contact: xiaoyan.zhang@intel.com +Description: + This attribute shows the response to the most recent operation + request it acted upon. The format is " + : ". + This file is readonly. + +What: /sys/class/tpm/tpmX/ppi/transition_action +Date: August 2012 +Contact: xiaoyan.zhang@intel.com +Description: + This attribute shows the platform-specific action that should + take place in order to transition to the BIOS for execution of + a requested operation. The format is ": ". + This file is readonly. + +What: /sys/class/tpm/tpmX/ppi/tcg_operations +Date: August 2012 +Contact: xiaoyan.zhang@intel.com +Description: + This attribute shows whether it is allowed to request an + operation to be executed in the pre-OS environment by the BIOS + for the requests defined by TCG, i.e. requests from 1 to 22. + The format is " : ". + This attribute is only supported by PPI version 1.2+. + This file is readonly. + +What: /sys/class/tpm/tpmX/ppi/vs_operations +Date: August 2012 +Contact: xiaoyan.zhang@intel.com +Description: + This attribute shows whether it is allowed to request an + operation to be executed in the pre-OS environment by the BIOS + for the verdor specific requests, i.e. requests from 128 to + 255. The format is same with tcg_operations. This attribute + is also only supported by PPI version 1.2+. + This file is readonly. -- cgit v1.3.1