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alistair23-linux/Documentation/ABI/testing/sysfs-class-cxl

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Please note that attributes that are shared between devices are stored in
the directory pointed to by the symlink device/.
For example, the real path of the attribute /sys/class/cxl/afu0.0s/irqs_max is
/sys/class/cxl/afu0.0s/device/irqs_max, i.e. /sys/class/cxl/afu0.0/irqs_max.
Slave contexts (eg. /sys/class/cxl/afu0.0s):
What: /sys/class/cxl/<afu>/afu_err_buf
Date: September 2014
Contact: linuxppc-dev@lists.ozlabs.org
Description: read only
AFU Error Buffer contents. The contents of this file are
application specific and depends on the AFU being used.
Applications interacting with the AFU can use this attribute
to know about the current error condition and take appropriate
action like logging the event etc.
What: /sys/class/cxl/<afu>/irqs_max
Date: September 2014
Contact: linuxppc-dev@lists.ozlabs.org
Description: read/write
Decimal value of maximum number of interrupts that can be
requested by userspace. The default on probe is the maximum
that hardware can support (eg. 2037). Write values will limit
userspace applications to that many userspace interrupts. Must
be >= irqs_min.
Users: https://github.com/ibm-capi/libcxl
What: /sys/class/cxl/<afu>/irqs_min
Date: September 2014
Contact: linuxppc-dev@lists.ozlabs.org
Description: read only
Decimal value of the minimum number of interrupts that
userspace must request on a CXL_START_WORK ioctl. Userspace may
omit the num_interrupts field in the START_WORK IOCTL to get
this minimum automatically.
Users: https://github.com/ibm-capi/libcxl
What: /sys/class/cxl/<afu>/mmio_size
Date: September 2014
Contact: linuxppc-dev@lists.ozlabs.org
Description: read only
Decimal value of the size of the MMIO space that may be mmaped
by userspace.
Users: https://github.com/ibm-capi/libcxl
What: /sys/class/cxl/<afu>/modes_supported
Date: September 2014
Contact: linuxppc-dev@lists.ozlabs.org
Description: read only
List of the modes this AFU supports. One per line.
Valid entries are: "dedicated_process" and "afu_directed"
Users: https://github.com/ibm-capi/libcxl
What: /sys/class/cxl/<afu>/mode
Date: September 2014
Contact: linuxppc-dev@lists.ozlabs.org
Description: read/write
The current mode the AFU is using. Will be one of the modes
given in modes_supported. Writing will change the mode
provided that no user contexts are attached.
Users: https://github.com/ibm-capi/libcxl
What: /sys/class/cxl/<afu>/prefault_mode
Date: September 2014
Contact: linuxppc-dev@lists.ozlabs.org
Description: read/write
Set the mode for prefaulting in segments into the segment table
cxl: Disable prefault_mode in Radix mode Currently we see a kernel-oops reported on Power-9 while attaching a context to an AFU, with radix-mode and sysfs attr 'prefault_mode' set to anything other than 'none'. The backtrace of the oops is of this form: Unable to handle kernel paging request for data at address 0x00000080 Faulting instruction address: 0xc00800000bcf3b20 cpu 0x1: Vector: 300 (Data Access) at [c00000037f003800] pc: c00800000bcf3b20: cxl_load_segment+0x178/0x290 [cxl] lr: c00800000bcf39f0: cxl_load_segment+0x48/0x290 [cxl] sp: c00000037f003a80 msr: 9000000000009033 dar: 80 dsisr: 40000000 current = 0xc00000037f280000 paca = 0xc0000003ffffe600 softe: 3 irq_happened: 0x01 pid = 3529, comm = afp_no_int <snip> cxl_prefault+0xfc/0x248 [cxl] process_element_entry_psl9+0xd8/0x1a0 [cxl] cxl_attach_dedicated_process_psl9+0x44/0x130 [cxl] native_attach_process+0xc0/0x130 [cxl] afu_ioctl+0x3f4/0x5e0 [cxl] do_vfs_ioctl+0xdc/0x890 ksys_ioctl+0x68/0xf0 sys_ioctl+0x40/0xa0 system_call+0x58/0x6c The issue is caused as on Power-8 the AFU attr 'prefault_mode' was used to improve initial storage fault performance by prefaulting process segments. However on Power-9 with radix mode we don't have Storage-Segments that we can prefault. Also prefaulting process Pages will be too costly and fine-grained. Hence, since the prefaulting mechanism doesn't makes sense of radix-mode, this patch updates prefault_mode_store() to not allow any other value apart from CXL_PREFAULT_NONE when radix mode is enabled. Fixes: f24be42aab37 ("cxl: Add psl9 specific code") Cc: stable@vger.kernel.org # v4.12+ Signed-off-by: Vaibhav Jain <vaibhav@linux.ibm.com> Acked-by: Frederic Barrat <fbarrat@linux.vnet.ibm.com> Acked-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-05-18 03:42:23 -06:00
when performing the START_WORK ioctl. Only applicable when
running under hashed page table mmu.
Possible values:
none: No prefaulting (default)
work_element_descriptor: Treat the work element
descriptor as an effective address and
prefault what it points to.
all: all segments process calling START_WORK maps.
Users: https://github.com/ibm-capi/libcxl
What: /sys/class/cxl/<afu>/reset
Date: September 2014
Contact: linuxppc-dev@lists.ozlabs.org
Description: write only
Writing 1 here will reset the AFU provided there are not
contexts active on the AFU.
Users: https://github.com/ibm-capi/libcxl
What: /sys/class/cxl/<afu>/api_version
Date: September 2014
Contact: linuxppc-dev@lists.ozlabs.org
Description: read only
Decimal value of the current version of the kernel/user API.
Users: https://github.com/ibm-capi/libcxl
What: /sys/class/cxl/<afu>/api_version_compatible
Date: September 2014
Contact: linuxppc-dev@lists.ozlabs.org
Description: read only
Decimal value of the the lowest version of the userspace API
this this kernel supports.
Users: https://github.com/ibm-capi/libcxl
AFU configuration records (eg. /sys/class/cxl/afu0.0/cr0):
An AFU may optionally export one or more PCIe like configuration records, known
as AFU configuration records, which will show up here (if present).
What: /sys/class/cxl/<afu>/cr<config num>/vendor
Date: February 2015
Contact: linuxppc-dev@lists.ozlabs.org
Description: read only
Hexadecimal value of the vendor ID found in this AFU
configuration record.
Users: https://github.com/ibm-capi/libcxl
What: /sys/class/cxl/<afu>/cr<config num>/device
Date: February 2015
Contact: linuxppc-dev@lists.ozlabs.org
Description: read only
Hexadecimal value of the device ID found in this AFU
configuration record.
Users: https://github.com/ibm-capi/libcxl
What: /sys/class/cxl/<afu>/cr<config num>/class
Date: February 2015
Contact: linuxppc-dev@lists.ozlabs.org
Description: read only
Hexadecimal value of the class code found in this AFU
configuration record.
Users: https://github.com/ibm-capi/libcxl
What: /sys/class/cxl/<afu>/cr<config num>/config
Date: February 2015
Contact: linuxppc-dev@lists.ozlabs.org
Description: read only
This binary file provides raw access to the AFU configuration
record. The format is expected to match the either the standard
or extended configuration space defined by the PCIe
specification.
Users: https://github.com/ibm-capi/libcxl
Master contexts (eg. /sys/class/cxl/afu0.0m)
What: /sys/class/cxl/<afu>m/mmio_size
Date: September 2014
Contact: linuxppc-dev@lists.ozlabs.org
Description: read only
Decimal value of the size of the MMIO space that may be mmaped
by userspace. This includes all slave contexts space also.
Users: https://github.com/ibm-capi/libcxl
What: /sys/class/cxl/<afu>m/pp_mmio_len
Date: September 2014
Contact: linuxppc-dev@lists.ozlabs.org
Description: read only
Decimal value of the Per Process MMIO space length.
Users: https://github.com/ibm-capi/libcxl
What: /sys/class/cxl/<afu>m/pp_mmio_off (not in a guest)
Date: September 2014
Contact: linuxppc-dev@lists.ozlabs.org
Description: read only
Decimal value of the Per Process MMIO space offset.
Users: https://github.com/ibm-capi/libcxl
Card info (eg. /sys/class/cxl/card0)
What: /sys/class/cxl/<card>/caia_version
Date: September 2014
Contact: linuxppc-dev@lists.ozlabs.org
Description: read only
Identifies the CAIA Version the card implements.
Users: https://github.com/ibm-capi/libcxl
What: /sys/class/cxl/<card>/psl_revision
Date: September 2014
Contact: linuxppc-dev@lists.ozlabs.org
Description: read only
Identifies the revision level of the PSL.
Users: https://github.com/ibm-capi/libcxl
What: /sys/class/cxl/<card>/base_image (not in a guest)
Date: September 2014
Contact: linuxppc-dev@lists.ozlabs.org
Description: read only
Identifies the revision level of the base image for devices
that support loadable PSLs. For FPGAs this field identifies
the image contained in the on-adapter flash which is loaded
during the initial program load.
Users: https://github.com/ibm-capi/libcxl
What: /sys/class/cxl/<card>/image_loaded (not in a guest)
Date: September 2014
Contact: linuxppc-dev@lists.ozlabs.org
Description: read only
Will return "user" or "factory" depending on the image loaded
onto the card.
Users: https://github.com/ibm-capi/libcxl
What: /sys/class/cxl/<card>/load_image_on_perst (not in a guest)
Date: December 2014
Contact: linuxppc-dev@lists.ozlabs.org
Description: read/write
Valid entries are "none", "user", and "factory".
"none" means PERST will not cause image to be loaded to the
card. A power cycle is required to load the image.
"none" could be useful for debugging because the trace arrays
are preserved.
"user" and "factory" means PERST will cause either the user or
user or factory image to be loaded.
Default is to reload on PERST whichever image the card has
loaded.
Users: https://github.com/ibm-capi/libcxl
What: /sys/class/cxl/<card>/reset
Date: October 2014
Contact: linuxppc-dev@lists.ozlabs.org
Description: write only
cxl: Prevent adapter reset if an active context exists This patch prevents resetting the cxl adapter via sysfs in presence of one or more active cxl_context on it. This protects against an unrecoverable error caused by PSL owning a dirty cache line even after reset and host tries to touch the same cache line. In case a force reset of the card is required irrespective of any active contexts, the int value -1 can be stored in the 'reset' sysfs attribute of the card. The patch introduces a new atomic_t member named contexts_num inside struct cxl that holds the number of active context attached to the card , which is checked against '0' before proceeding with the reset. To prevent against a race condition where a context is activated just after reset check is performed, the contexts_num is atomically set to '-1' after reset-check to indicate that no more contexts can be activated on the card anymore. Before activating a context we atomically test if contexts_num is non-negative and if so, increment its value by one. In case the value of contexts_num is negative then it indicates that the card is about to be reset and context activation is error-ed out at that point. Fixes: 62fa19d4b4fd ("cxl: Add ability to reset the card") Cc: stable@vger.kernel.org # v4.0+ Acked-by: Frederic Barrat <fbarrat@linux.vnet.ibm.com> Reviewed-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com> Signed-off-by: Vaibhav Jain <vaibhav@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-10-14 03:38:36 -06:00
Writing 1 will issue a PERST to card provided there are no
contexts active on any one of the card AFUs. This may cause
the card to reload the FPGA depending on load_image_on_perst.
Writing -1 will do a force PERST irrespective of any active
contexts on the card AFUs.
Users: https://github.com/ibm-capi/libcxl
What: /sys/class/cxl/<card>/perst_reloads_same_image (not in a guest)
Date: July 2015
Contact: linuxppc-dev@lists.ozlabs.org
Description: read/write
Trust that when an image is reloaded via PERST, it will not
have changed.
0 = don't trust, the image may be different (default)
1 = trust that the image will not change.
Users: https://github.com/ibm-capi/libcxl
What: /sys/class/cxl/<card>/psl_timebase_synced
Date: March 2016
Contact: linuxppc-dev@lists.ozlabs.org
Description: read only
Returns 1 if the psl timebase register is synchronized
with the core timebase register, 0 otherwise.
Users: https://github.com/ibm-capi/libcxl
What: /sys/class/cxl/<card>/tunneled_ops_supported
Date: May 2018
Contact: linuxppc-dev@lists.ozlabs.org
Description: read only
Returns 1 if tunneled operations are supported in capi mode,
0 otherwise.
Users: https://github.com/ibm-capi/libcxl