linux-kernel - [PATCH v6 18/24] x86/resctrl: Make ctrlval arrays the same size

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Message-Id: <20210715173043.14222-19-james.morse@arm.com>
Date:   Thu, 15 Jul 2021 17:30:37 +0000
From:   James Morse <james.morse@....com>
To:     x86@...nel.org, linux-kernel@...r.kernel.org
Cc:     Fenghua Yu <fenghua.yu@...el.com>,
        Reinette Chatre <reinette.chatre@...el.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        H Peter Anvin <hpa@...or.com>,
        Babu Moger <Babu.Moger@....com>,
        James Morse <james.morse@....com>,
        shameerali.kolothum.thodi@...wei.com,
        Jamie Iles <jamie@...iainc.com>,
        D Scott Phillips OS <scott@...amperecomputing.com>,
        lcherian@...vell.com, bobo.shaobowang@...wei.com
Subject: [PATCH v6 18/24] x86/resctrl: Make ctrlval arrays the same size

The CODE and DATA resources report a num_closid that is half the
actual size supported by the hardware. This behaviour is visible
to user-space when CDP is enabled.
The CODE and DATA resources have their own ctrlval arrays which are half
the size of the underlying hardware because num_closid was already
adjusted. One holds the odd configurations values, the other even.

Before the CDP resources can be merged, the 'half the closids'
behaviour needs to be implemented by schemata_list_create(), but
this causes the ctrl_val[] array to be full sized.

Remove the logic from the architecture specific rdt_get_cdp_config()
setup, and add it to schemata_list_create(). Functions that
walk all the configurations, such as domain_setup_ctrlval() and
reset_all_ctrls(), take num_closid directly from struct rdt_hw_resource
also have to halve num_closid as only the lower half of each array is
in use. domain_setup_ctrlval() and reset_all_ctrls() both copy
struct rdt_hw_resource's num_closid to a struct msr_param. Correct
the value here. This is temporary as a subsequent patch will merge
all three ctrl_val[] arrays such that when CDP is in use, the
CODA/DATA layout in the array matches the hardware. reset_all_ctrls()'s
loop over the whole of ctrl_val[] is not touched as this is harmless,
and will be required as it is once the resources are merged.

Reviewed-by: Jamie Iles <jamie@...iainc.com>
Reviewed-by: Reinette Chatre <reinette.chatre@...el.com>
Tested-by: Babu Moger <babu.moger@....com>
Signed-off-by: James Morse <james.morse@....com>
---
Changes since v4:
 * Added missing words to the commit message, fixed a typo.

No changes since v3.

Changes since v2:
 * Shuffled commit message,
---
 arch/x86/kernel/cpu/resctrl/core.c     | 10 +++++++++-
 arch/x86/kernel/cpu/resctrl/rdtgroup.c |  9 +++++++++
 2 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c
index 755118a9ef38..9f8be5ee5e8a 100644
--- a/arch/x86/kernel/cpu/resctrl/core.c
+++ b/arch/x86/kernel/cpu/resctrl/core.c
@@ -363,7 +363,7 @@ static void rdt_get_cdp_config(int level, int type)
 	struct rdt_resource *r = &rdt_resources_all[type].r_resctrl;
 	struct rdt_hw_resource *hw_res = resctrl_to_arch_res(r);
 
-	hw_res->num_closid = hw_res_l->num_closid / 2;
+	hw_res->num_closid = hw_res_l->num_closid;
 	r->cache.cbm_len = r_l->cache.cbm_len;
 	r->default_ctrl = r_l->default_ctrl;
 	r->cache.shareable_bits = r_l->cache.shareable_bits;
@@ -549,6 +549,14 @@ static int domain_setup_ctrlval(struct rdt_resource *r, struct rdt_domain *d)
 
 	m.low = 0;
 	m.high = hw_res->num_closid;
+
+	/*
+	 * temporary: the array is full-size, but cat_wrmsr() still re-maps
+	 * the index.
+	 */
+	if (hw_res->conf_type != CDP_NONE)
+		m.high /= 2;
+
 	hw_res->msr_update(d, &m, r);
 	return 0;
 }
diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index 61037b239327..299af12c9fe4 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -2154,6 +2154,8 @@ static int schemata_list_create(void)
 		s->res = r;
 		s->conf_type = resctrl_to_arch_res(r)->conf_type;
 		s->num_closid = resctrl_arch_get_num_closid(r);
+		if (resctrl_arch_get_cdp_enabled(r->rid))
+			s->num_closid /= 2;
 
 		ret = snprintf(s->name, sizeof(s->name), r->name);
 		if (ret >= sizeof(s->name)) {
@@ -2376,6 +2378,13 @@ static int reset_all_ctrls(struct rdt_resource *r)
 	msr_param.low = 0;
 	msr_param.high = hw_res->num_closid;
 
+	/*
+	 * temporary: the array is full-sized, but cat_wrmsr() still re-maps
+	 * the index.
+	 */
+	if (hw_res->cdp_enabled)
+		msr_param.high /= 2;
+
 	/*
 	 * Disable resource control for this resource by setting all
 	 * CBMs in all domains to the maximum mask value. Pick one CPU
-- 
2.30.2