Babu Moger
e5572e66d2
commit67bf649344upstream. AMD systems support zero CBM (capacity bit mask) for cache allocation. That is reflected in rdt_init_res_defs_amd() by: r->cache.arch_has_empty_bitmaps = true; However given the unified code in cbm_validate(), checking for: val == 0 && !arch_has_empty_bitmaps is not enough because of another check in cbm_validate(): if ((zero_bit - first_bit) < r->cache.min_cbm_bits) The default value of r->cache.min_cbm_bits = 1. Leading to: $ cd /sys/fs/resctrl $ mkdir foo $ cd foo $ echo L3:0=0 > schemata -bash: echo: write error: Invalid argument $ cat /sys/fs/resctrl/info/last_cmd_status Need at least 1 bits in the mask Initialize the min_cbm_bits to 0 for AMD. Also, remove the default setting of min_cbm_bits and initialize it separately. After the fix: $ cd /sys/fs/resctrl $ mkdir foo $ cd foo $ echo L3:0=0 > schemata $ cat /sys/fs/resctrl/info/last_cmd_status ok Fixes:316e7f901f("x86/resctrl: Add struct rdt_cache::arch_has_{sparse, empty}_bitmaps") Co-developed-by: Stephane Eranian <eranian@google.com> Signed-off-by: Stephane Eranian <eranian@google.com> Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Ingo Molnar <mingo@kernel.org> Reviewed-by: James Morse <james.morse@arm.com> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghua.yu@intel.com> Cc: <stable@vger.kernel.org> Link: https://lore.kernel.org/lkml/20220517001234.3137157-1-eranian@google.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.