linux-kernel - [PATCH v2 22/23] x86/resctrl: Add resctrl_rmid_realloc_limit to abstract x86's boot_cpu

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20211001160302.31189-23-james.morse@arm.com>
Date:   Fri,  1 Oct 2021 16:03:01 +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,
        tan.shaopeng@...itsu.com
Subject: [PATCH v2 22/23] x86/resctrl: Add resctrl_rmid_realloc_limit to abstract x86's boot_cpu_data

resctrl_rmid_realloc_threshold can be set by user-space. The maximum
value is specified by the architecture.

Currently max_threshold_occ_write() reads the maximum value from
boot_cpu_data.x86_cache_size, which is not portable to another
architecture.

Add resctrl_rmid_realloc_limit to describe the maximum size in bytes
that user-space can set the threshold to.

Signed-off-by: James Morse <james.morse@....com>
---
 arch/x86/kernel/cpu/resctrl/monitor.c  | 9 +++++++--
 arch/x86/kernel/cpu/resctrl/rdtgroup.c | 2 +-
 include/linux/resctrl.h                | 1 +
 3 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/cpu/resctrl/monitor.c b/arch/x86/kernel/cpu/resctrl/monitor.c
index d0c3a3db5f2a..becc7eb0cb7e 100644
--- a/arch/x86/kernel/cpu/resctrl/monitor.c
+++ b/arch/x86/kernel/cpu/resctrl/monitor.c
@@ -64,6 +64,11 @@ unsigned int rdt_mon_features;
  */
 unsigned int resctrl_rmid_realloc_threshold;
 
+/*
+ * This is the maximum value for the reallocation threshold, in bytes.
+ */
+unsigned int resctrl_rmid_realloc_limit;
+
 #define CF(cf)	((unsigned long)(1048576 * (cf) + 0.5))
 
 /*
@@ -739,9 +744,9 @@ int rdt_get_mon_l3_config(struct rdt_resource *r)
 {
 	unsigned int mbm_offset = boot_cpu_data.x86_cache_mbm_width_offset;
 	struct rdt_hw_resource *hw_res = resctrl_to_arch_res(r);
-	unsigned int cl_size = boot_cpu_data.x86_cache_size;
 	int ret;
 
+	resctrl_rmid_realloc_limit = boot_cpu_data.x86_cache_size * 1024;
 	hw_res->mon_scale = boot_cpu_data.x86_cache_occ_scale;
 	r->num_rmid = boot_cpu_data.x86_cache_max_rmid + 1;
 	hw_res->mbm_width = MBM_CNTR_WIDTH_BASE;
@@ -758,7 +763,7 @@ int rdt_get_mon_l3_config(struct rdt_resource *r)
 	 *
 	 * For a 35MB LLC and 56 RMIDs, this is ~1.8% of the LLC.
 	 */
-	resctrl_rmid_realloc_threshold = cl_size * 1024 / r->num_rmid;
+	resctrl_rmid_realloc_threshold = resctrl_rmid_realloc_limit / r->num_rmid;
 
 	ret = dom_data_init(r);
 	if (ret)
diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index bf0d13a5ce1f..f93b52ab6580 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -1059,7 +1059,7 @@ static ssize_t max_threshold_occ_write(struct kernfs_open_file *of,
 	if (ret)
 		return ret;
 
-	if (bytes > (boot_cpu_data.x86_cache_size * 1024))
+	if (bytes > resctrl_rmid_realloc_limit)
 		return -EINVAL;
 
 	resctrl_rmid_realloc_threshold = bytes;
diff --git a/include/linux/resctrl.h b/include/linux/resctrl.h
index 8d297d014a16..5b1452bdbd7e 100644
--- a/include/linux/resctrl.h
+++ b/include/linux/resctrl.h
@@ -247,5 +247,6 @@ void resctrl_arch_reset_rmid(struct rdt_resource *r, struct rdt_domain *d,
 			     u32 rmid, enum resctrl_event_id eventid);
 
 extern unsigned int resctrl_rmid_realloc_threshold;
+extern unsigned int resctrl_rmid_realloc_limit;
 
 #endif /* _RESCTRL_H */
-- 
2.30.2