This series adds the support for L3 Smart Data Cache Injection Allocation Enforcement (SDCIAE) to resctrl infrastructure. It is refered to as "io_alloc" in resctrl subsystem. Upcoming AMD hardware implements Smart Data Cache Injection (SDCI). Smart Data Cache Injection (SDCI) is a mechanism that enables direct insertion of data from I/O devices into the L3 cache. By directly caching data from I/O devices rather than first storing the I/O data in DRAM, SDCI reduces demands on DRAM bandwidth and reduces latency to the processor consuming the I/O data. The SDCIAE (SDCI Allocation Enforcement) PQE feature allows system software to control the portion of the L3 cache used for SDCI devices. When enabled, SDCIAE forces all SDCI lines to be placed into the L3 cache partitions identified by the highest-supported L3_MASK_n register, where n is the maximum supported CLOSID. The feature details are documented in the APM listed below [1]. [1] AMD64 Architecture Programmer's Manual Volume 2: System Programming Publication # 24593 Revision 3.41 section 19.4.7 L3 Smart Data Cache Injection Allocation Enforcement (SDCIAE) Link: https://bugzilla.kernel.org/show_bug.cgi?id=206537 The feature requires linux support of TPH (TLP Processing Hints). The support is available in linux kernel after the commit 48d0fd2b903e3 ("PCI/TPH: Add TPH documentation") The patches are based on top of commit 84c319145cbad6 Merge branch into ("tip/master: 'x86/nmi'") # Linux Implementation Feature adds following interface files when the resctrl "io_alloc" feature is supported on L3 resource: /sys/fs/resctrl/info/L3/io_alloc: Report the feature status. Enable/disable the feature by writing to the interface. /sys/fs/resctrl/info/L3/io_alloc_cbm: List the Capacity Bit Masks (CBMs) available for I/O devices when io_alloc feature is enabled. Configure the CBM by writing to the interface. # Examples: a. Check if io_alloc feature is available #mount -t resctrl resctrl /sys/fs/resctrl/ # cat /sys/fs/resctrl/info/L3/io_alloc disabled b. Enable the io_alloc feature. # echo 1 > /sys/fs/resctrl/info/L3/io_alloc # cat /sys/fs/resctrl/info/L3/io_alloc enabled c. Check the CBM values for the io_alloc feature. # cat /sys/fs/resctrl/info/L3/io_alloc_cbm L3:0=ffff;1=ffff d. Change the CBM value for the domain 1: # echo L3:1=FF > /sys/fs/resctrl/info/L3/io_alloc_cbm # cat /sys/fs/resctrl/info/L3/io_alloc_cbm L3:0=ffff;1=00ff d. Disable io_alloc feature and exit. # echo 0 > /sys/fs/resctrl/info/L3/io_alloc # cat /sys/fs/resctrl/info/L3/io_alloc disabled #umount /sys/fs/resctrl/ --- v4: The "io_alloc" interface will report "enabled/disabled/not supported" instead of 0 or 1.. Updated resctrl_io_alloc_closid_get() to verify the max closid availability using closids_supported(). Updated the documentation for "shareable_bits" and "bit_usage". NOTE: io_alloc is about specific CLOS. rdt_bit_usage_show() is not designed handle bit_usage for specific CLOS. Its about overall system. So, we cannot really tell the user which CLOS is shared across both hardware and software. This is something we need to discuss. Introduced io_alloc_init() to initialize fflags. Printed the group name when io_alloc enablement fails to help user. Added rdtgroup_mutex before rdt_last_cmd_puts() in resctrl_io_alloc_cbm_show(). Returned -ENODEV when resource type is CDP_DATA. Kept the resource name while printing the CBM (L3:0=ffff) that way we dont have to change show_doms() just for this feature and it is consistant across all the schemata display. Added new patch to call parse_cbm() directly to avoid code duplication. Checked all the series(v1-v3) again to verify if I missed any comment. v3: Rewrote commit log for the last 3 patches. Changed the text to bit more generic than the AMD specific feature. Added AMD feature specifics in the end. Renamed the rdt_get_sdciae_alloc_cfg() to rdt_set_io_alloc_capable(). Renamed the _resctrl_io_alloc_enable() to _resctrl_sdciae_enable() as it is arch specific. Changed the return to void in _resctrl_sdciae_enable() instead of int. The number of CLOSIDs is determined based on the minimum supported across all resources (in closid_init). It needs to match the max supported on the resource. Added the check to verify if MAX CLOSID availability on the system. Added CDP check to make sure io_alloc is configured in CDP_CODE. Highest CLOSID corresponds to CDP_CODE. Added resctrl_io_alloc_closid_free() to free the io_alloc CLOSID. Added errors in few cases when CLOSID allocation fails. Fixes splat reported when info/L3/bit_usage is accesed when io_alloc is enabled. https://lore.kernel.org/lkml/SJ1PR11MB60837B532254E7B23BC27E84FC052@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/ v2: Added dependancy on X86_FEATURE_CAT_L3 Removed the "" in CPU feature definition. Changed sdciae_capable to io_alloc_capable to make it as generic feature. Moved io_alloc_capable field in struct resctrl_cache. Changed the name of few arch functions similar to ABMC series. resctrl_arch_get_io_alloc_enabled() resctrl_arch_io_alloc_enable() Renamed the feature to "io_alloc". Added generic texts for the feature in commit log and resctrl.rst doc. Added resctrl_io_alloc_init_cat() to initialize io_alloc to default values when enabled. Fixed io_alloc interface to show only on L3 resource. Added the locks while processing io_alloc CBMs. Previous versions: v3: https://lore.kernel.org/lkml/cover.1738272037.git.babu.moger@xxxxxxx/ v2: https://lore.kernel.org/lkml/cover.1734556832.git.babu.moger@xxxxxxx/ v1: https://lore.kernel.org/lkml/cover.1723824984.git.babu.moger@xxxxxxx/ Babu Moger (8): x86/cpufeatures: Add support for L3 Smart Data Cache Injection Allocation Enforcement x86/resctrl: Add SDCIAE feature in the command line options x86/resctrl: Detect io_alloc feature x86/resctrl: Implement "io_alloc" enable/disable handlers x86/resctrl: Add user interface to enable/disable io_alloc feature x86/resctrl: Introduce interface to display io_alloc CBMs x86/resctrl: Modify rdt_parse_data to pass mode and CLOSID x86/resctrl: Introduce interface to modify io_alloc Capacity Bit Masks .../admin-guide/kernel-parameters.txt | 2 +- Documentation/arch/x86/resctrl.rst | 55 +++ arch/x86/include/asm/cpufeatures.h | 1 + arch/x86/include/asm/msr-index.h | 1 + arch/x86/kernel/cpu/cpuid-deps.c | 1 + arch/x86/kernel/cpu/resctrl/core.c | 9 + arch/x86/kernel/cpu/resctrl/ctrlmondata.c | 35 +- arch/x86/kernel/cpu/resctrl/internal.h | 19 + arch/x86/kernel/cpu/resctrl/rdtgroup.c | 372 +++++++++++++++++- arch/x86/kernel/cpu/scattered.c | 1 + include/linux/resctrl.h | 12 + 11 files changed, 487 insertions(+), 21 deletions(-) -- 2.34.1
