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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/debugfs-pcie-ptm
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/kernel/debug/pcie_ptm_*/local_clock
+Date: May 2025
+Contact: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
+Description:
+ (RO) PTM local clock in nanoseconds. Applicable for both Root
+ Complex and Endpoint controllers.
+
+What: /sys/kernel/debug/pcie_ptm_*/master_clock
+Date: May 2025
+Contact: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
+Description:
+ (RO) PTM master clock in nanoseconds. Applicable only for
+ Endpoint controllers.
+
+What: /sys/kernel/debug/pcie_ptm_*/t1
+Date: May 2025
+Contact: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
+Description:
+ (RO) PTM T1 timestamp in nanoseconds. Applicable only for
+ Endpoint controllers.
+
+What: /sys/kernel/debug/pcie_ptm_*/t2
+Date: May 2025
+Contact: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
+Description:
+ (RO) PTM T2 timestamp in nanoseconds. Applicable only for
+ Root Complex controllers.
+
+What: /sys/kernel/debug/pcie_ptm_*/t3
+Date: May 2025
+Contact: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
+Description:
+ (RO) PTM T3 timestamp in nanoseconds. Applicable only for
+ Root Complex controllers.
+
+What: /sys/kernel/debug/pcie_ptm_*/t4
+Date: May 2025
+Contact: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
+Description:
+ (RO) PTM T4 timestamp in nanoseconds. Applicable only for
+ Endpoint controllers.
+
+What: /sys/kernel/debug/pcie_ptm_*/context_update
+Date: May 2025
+Contact: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
+Description:
+ (RW) Control the PTM context update mode. Applicable only for
+ Endpoint controllers.
+
+ Following values are supported:
+
+ * auto = PTM context auto update trigger for every 10ms
+
+ * manual = PTM context manual update. Writing 'manual' to this
+ file triggers PTM context update (default)
+
+What: /sys/kernel/debug/pcie_ptm_*/context_valid
+Date: May 2025
+Contact: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
+Description:
+ (RW) Control the PTM context validity (local clock timing).
+ Applicable only for Root Complex controllers. PTM context is
+ invalidated by hardware if the Root Complex enters low power
+ mode or changes link frequency.
+
+ Following values are supported:
+
+ * 0 = PTM context invalid (default)
+
+ * 1 = PTM context valid