Commit b045c215 authored Sep 02, 2022 by James Morse Committed by Borislav Petkov Sep 22, 2022

x86/resctrl: Abstract and use supports_mba_mbps()



To determine whether the mba_MBps option to resctrl should be supported,
resctrl tests the boot CPUs' x86_vendor.

This isn't portable, and needs abstracting behind a helper so this check
can be part of the filesystem code that moves to /fs/.

Re-use the tests set_mba_sc() does to determine if the mba_sc is supported
on this system. An 'alloc_capable' test is added so that support for the
controls isn't implied by the 'delay_linear' property, which is always
true for MPAM. Because mbm_update() only update mba_sc if the mbm_local
counters are enabled, supports_mba_mbps() checks is_mbm_local_enabled().
(instead of using is_mbm_enabled(), which checks both).

Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Jamie Iles <quic_jiles@quicinc.com>
Reviewed-by: Shaopeng Tan <tan.shaopeng@fujitsu.com>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Tested-by: Xin Hao <xhao@linux.alibaba.com>
Tested-by: Shaopeng Tan <tan.shaopeng@fujitsu.com>
Tested-by: Cristian Marussi <cristian.marussi@arm.com>
Link: https://lore.kernel.org/r/20220902154829.30399-8-james.morse@arm.com

parent 1644dfe7

arch/x86/kernel/cpu/resctrl/rdtgroup.c

+14 −5

Original line number	Diff line number	Diff line
		@@ -1890,17 +1890,26 @@ void rdt_domain_reconfigure_cdp(struct rdt_resource *r)
		}

		/*
		* Enable or disable the MBA software controller
		* which helps user specify bandwidth in MBps.
		* MBA software controller is supported only if
		* MBM is supported and MBA is in linear scale.
		*/
		static bool supports_mba_mbps(void)
		{
		struct rdt_resource *r = &rdt_resources_all[RDT_RESOURCE_MBA].r_resctrl;

		return (is_mbm_local_enabled() &&
		r->alloc_capable && is_mba_linear());
		}

		/*
		* Enable or disable the MBA software controller
		* which helps user specify bandwidth in MBps.
		*/
		static int set_mba_sc(bool mba_sc)
		{
		struct rdt_resource *r = &rdt_resources_all[RDT_RESOURCE_MBA].r_resctrl;

		if (!is_mbm_enabled() \|\| !is_mba_linear() \|\|
		mba_sc == is_mba_sc(r))
		if (!supports_mba_mbps() \|\| mba_sc == is_mba_sc(r))
		return -EINVAL;

		r->membw.mba_sc = mba_sc;
		@@ -2255,7 +2264,7 @@ static int rdt_parse_param(struct fs_context fc, struct fs_parameter param)
		ctx->enable_cdpl2 = true;
		return 0;
		case Opt_mba_mbps:
		if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL)
		if (!supports_mba_mbps())
		return -EINVAL;
		ctx->enable_mba_mbps = true;
		return 0;