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-ata | 140 ++++++++++++++++++++++++++++++++++++ 1 file changed, 140 insertions(+) create mode 100644 Documentation/ABI/testing/sysfs-ata (limited to 'Documentation/ABI/testing/sysfs-ata') diff --git a/Documentation/ABI/testing/sysfs-ata b/Documentation/ABI/testing/sysfs-ata new file mode 100644 index 000000000..3daecac48 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-ata @@ -0,0 +1,140 @@ +What: /sys/class/ata_* +Description: + Provide a place in sysfs for storing the ATA topology of the + system. This allows retrieving various information about ATA + objects. + +Files under /sys/class/ata_port +------------------------------- + +For each port, a directory ataX is created where X is the ata_port_id of the +port. The device parent is the ata host device. + + +What: /sys/class/ata_port/ataX/nr_pmp_links +What: /sys/class/ata_port/ataX/idle_irq +Date: May, 2010 +KernelVersion: v2.6.37 +Contact: Gwendal Grignou +Description: + nr_pmp_links: (RO) If a SATA Port Multiplier (PM) is + connected, the number of links behind it. + + idle_irq: (RO) Number of IRQ received by the port while + idle [some ata HBA only]. + + +What: /sys/class/ata_port/ataX/port_no +Date: May, 2013 +KernelVersion: v3.11 +Contact: Gwendal Grignou +Description: + (RO) Host local port number. While registering host controller, + port numbers are tracked based upon number of ports available on + the controller. This attribute is needed by udev for composing + persistent links in /dev/disk/by-path. + +Files under /sys/class/ata_link +------------------------------- + +Behind each port, there is a ata_link. If there is a SATA PM in the topology, 15 +ata_link objects are created. + +If a link is behind a port, the directory name is linkX, where X is ata_port_id +of the port. If a link is behind a PM, its name is linkX.Y where X is +ata_port_id of the parent port and Y the PM port. + + +What: /sys/class/ata_link/linkX[.Y]/hw_sata_spd_limit +What: /sys/class/ata_link/linkX[.Y]/sata_spd_limit +What: /sys/class/ata_link/linkX[.Y]/sata_spd +Date: May, 2010 +KernelVersion: v2.6.37 +Contact: Gwendal Grignou +Description: + hw_sata_spd_limit: (RO) Maximum speed supported by the + connected SATA device. + + sata_spd_limit: (RO) Maximum speed imposed by libata. + + sata_spd: (RO) Current speed of the link + eg. 1.5, 3 Gbps etc. + + +Files under /sys/class/ata_device +--------------------------------- + +Behind each link, up to two ata devices are created. +The name of the directory is devX[.Y].Z where: +- X is ata_port_id of the port where the device is connected, +- Y the port of the PM if any, and +- Z the device id: for PATA, there is usually 2 devices [0,1], only 1 for SATA. + + +What: /sys/class/ata_device/devX[.Y].Z/spdn_cnt +What: /sys/class/ata_device/devX[.Y].Z/gscr +What: /sys/class/ata_device/devX[.Y].Z/ering +What: /sys/class/ata_device/devX[.Y].Z/id +What: /sys/class/ata_device/devX[.Y].Z/pio_mode +What: /sys/class/ata_device/devX[.Y].Z/xfer_mode +What: /sys/class/ata_device/devX[.Y].Z/dma_mode +What: /sys/class/ata_device/devX[.Y].Z/class +Date: May, 2010 +KernelVersion: v2.6.37 +Contact: Gwendal Grignou +Description: + spdn_cnt: (RO) Number of times libata decided to lower the + speed of link due to errors. + + gscr: (RO) Cached result of the dump of PM GSCR + register. Valid registers are: + + 0: SATA_PMP_GSCR_PROD_ID, + 1: SATA_PMP_GSCR_REV, + 2: SATA_PMP_GSCR_PORT_INFO, + 32: SATA_PMP_GSCR_ERROR, + 33: SATA_PMP_GSCR_ERROR_EN, + 64: SATA_PMP_GSCR_FEAT, + 96: SATA_PMP_GSCR_FEAT_EN, + 130: SATA_PMP_GSCR_SII_GPIO + + Only valid if the device is a PM. + + ering: (RO) Formatted output of the error ring of the + device. + + id: (RO) Cached result of IDENTIFY command, as + described in ATA8 7.16 and 7.17. Only valid if + the device is not a PM. + + pio_mode: (RO) PIO transfer mode used by the device. + Mostly used by PATA devices. + + xfer_mode: (RO) Current transfer mode. Mostly used by + PATA devices. + + dma_mode: (RO) DMA transfer mode used by the device. + Mostly used by PATA devices. + + class: (RO) Device class. Can be "ata" for disk, + "atapi" for packet device, "pmp" for PM, or + "none" if no device was found behind the link. + + +What: /sys/class/ata_device/devX[.Y].Z/trim +Date: May, 2015 +KernelVersion: v4.10 +Contact: Gwendal Grignou +Description: + (RO) Shows the DSM TRIM mode currently used by the device. Valid + values are: + + unsupported: Drive does not support DSM TRIM + + unqueued: Drive supports unqueued DSM TRIM only + + queued: Drive supports queued DSM TRIM + + forced_unqueued: Drive's queued DSM support is known to + be buggy and only unqueued TRIM commands + are sent -- cgit v1.3.1