Commit 556d2892 authored by Babu Moger's avatar Babu Moger Committed by Borislav Petkov (AMD)
Browse files

x86,fs/resctrl: Implement "io_alloc" enable/disable handlers 



"io_alloc" is the generic name of the new resctrl feature that enables system
software to configure the portion of cache allocated for I/O traffic. On AMD
systems, "io_alloc" resctrl feature is backed by AMD's L3 Smart Data Cache
Injection Allocation Enforcement (SDCIAE).

Introduce the architecture-specific functions that resctrl fs should call to
enable, disable, or check status of the "io_alloc" feature. Change SDCIAE state
by setting (to enable) or clearing (to disable) bit 1 of
MSR_IA32_L3_QOS_EXT_CFG on all logical processors within the cache domain.

Signed-off-by: default avatarBabu Moger <babu.moger@amd.com>
Signed-off-by: default avatarBorislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: default avatarReinette Chatre <reinette.chatre@intel.com>
Link: https://patch.msgid.link/9e9070100c320eab5368e088a3642443dee95ed7.1762995456.git.babu.moger@amd.com
parent 7923ae76

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

+40 −0
Original line number Diff line number Diff line
@@ -91,3 +91,43 @@ u32 resctrl_arch_get_config(struct rdt_resource *r, struct rdt_ctrl_domain *d, 


	return hw_dom->ctrl_val[idx];

}



bool resctrl_arch_get_io_alloc_enabled(struct rdt_resource *r)

{

	return resctrl_to_arch_res(r)->sdciae_enabled;

}



static void resctrl_sdciae_set_one_amd(void *arg)

{

	bool *enable = arg;



	if (*enable)

		msr_set_bit(MSR_IA32_L3_QOS_EXT_CFG, SDCIAE_ENABLE_BIT);

	else

		msr_clear_bit(MSR_IA32_L3_QOS_EXT_CFG, SDCIAE_ENABLE_BIT);

}



static void _resctrl_sdciae_enable(struct rdt_resource *r, bool enable)

{

	struct rdt_ctrl_domain *d;



	/* Walking r->ctrl_domains, ensure it can't race with cpuhp */

	lockdep_assert_cpus_held();



	/* Update MSR_IA32_L3_QOS_EXT_CFG MSR on all the CPUs in all domains */

	list_for_each_entry(d, &r->ctrl_domains, hdr.list)

		on_each_cpu_mask(&d->hdr.cpu_mask, resctrl_sdciae_set_one_amd, &enable, 1);

}



int resctrl_arch_io_alloc_enable(struct rdt_resource *r, bool enable)

{

	struct rdt_hw_resource *hw_res = resctrl_to_arch_res(r);



	if (hw_res->r_resctrl.cache.io_alloc_capable &&

	    hw_res->sdciae_enabled != enable) {

		_resctrl_sdciae_enable(r, enable);

		hw_res->sdciae_enabled = enable;

	}



	return 0;

}

arch/x86/kernel/cpu/resctrl/internal.h

+5 −0
Original line number Diff line number Diff line
@@ -46,6 +46,9 @@ struct arch_mbm_state { 
#define ABMC_EXTENDED_EVT_ID		BIT(31)

#define ABMC_EVT_ID			BIT(0)



/* Setting bit 1 in MSR_IA32_L3_QOS_EXT_CFG enables the SDCIAE feature. */

#define SDCIAE_ENABLE_BIT		1



/**

 * struct rdt_hw_ctrl_domain - Arch private attributes of a set of CPUs that share

 *			       a resource for a control function
@@ -112,6 +115,7 @@ struct msr_param { 
 * @mbm_width:		Monitor width, to detect and correct for overflow.

 * @cdp_enabled:	CDP state of this resource

 * @mbm_cntr_assign_enabled:	ABMC feature is enabled

 * @sdciae_enabled:	SDCIAE feature (backing "io_alloc") is enabled.

 *

 * Members of this structure are either private to the architecture

 * e.g. mbm_width, or accessed via helpers that provide abstraction. e.g.
@@ -126,6 +130,7 @@ struct rdt_hw_resource { 
	unsigned int		mbm_width;

	bool			cdp_enabled;

	bool			mbm_cntr_assign_enabled;

	bool			sdciae_enabled;

};



static inline struct rdt_hw_resource *resctrl_to_arch_res(struct rdt_resource *r)

include/linux/resctrl.h

+21 −0
Original line number Diff line number Diff line
@@ -657,6 +657,27 @@ void resctrl_arch_reset_cntr(struct rdt_resource *r, struct rdt_mon_domain *d, 
			     u32 closid, u32 rmid, int cntr_id,

			     enum resctrl_event_id eventid);



/**

 * resctrl_arch_io_alloc_enable() - Enable/disable io_alloc feature.

 * @r:		The resctrl resource.

 * @enable:	Enable (true) or disable (false) io_alloc on resource @r.

 *

 * This can be called from any CPU.

 *

 * Return:

 * 0 on success, <0 on error.

 */

int resctrl_arch_io_alloc_enable(struct rdt_resource *r, bool enable);



/**

 * resctrl_arch_get_io_alloc_enabled() - Get io_alloc feature state.

 * @r:		The resctrl resource.

 *

 * Return:

 * true if io_alloc is enabled or false if disabled.

 */

bool resctrl_arch_get_io_alloc_enabled(struct rdt_resource *r);



extern unsigned int resctrl_rmid_realloc_threshold;

extern unsigned int resctrl_rmid_realloc_limit;