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authorReinette Chatre <reinette.chatre@intel.com>2018-09-15 14:58:20 -0700
committerThomas Gleixner <tglx@linutronix.de>2018-09-18 23:38:05 +0200
commitf968dc119a159a95628a20de2a2dcc913d0a82d7 (patch)
treece739143e31e50b2ac03f46d9b535e86e9e24dfb /arch
parent753694a8df318f204a0ac1303de136def16f2e9c (diff)
downloadlinux-f968dc119a159a95628a20de2a2dcc913d0a82d7.tar.bz2
x86/intel_rdt: Fix size reporting of MBA resource
Chen Yu reported a divide-by-zero error when accessing the 'size' resctrl file when a MBA resource is enabled. divide error: 0000 [#1] SMP PTI CPU: 93 PID: 1929 Comm: cat Not tainted 4.19.0-rc2-debug-rdt+ #25 RIP: 0010:rdtgroup_cbm_to_size+0x7e/0xa0 Call Trace: rdtgroup_size_show+0x11a/0x1d0 seq_read+0xd8/0x3b0 Quoting Chen Yu's report: This is because for MB resource, the r->cache.cbm_len is zero, thus calculating size in rdtgroup_cbm_to_size() will trigger the exception. Fix this issue in the 'size' file by getting correct memory bandwidth value which is in MBps when MBA software controller is enabled or in percentage when MBA software controller is disabled. Fixes: d9b48c86eb38 ("x86/intel_rdt: Display resource groups' allocations in bytes") Reported-by: Chen Yu <yu.c.chen@intel.com> Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Fenghua Yu <fenghua.yu@intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Chen Yu <yu.c.chen@intel.com> Cc: "H Peter Anvin" <hpa@zytor.com> Cc: "Tony Luck" <tony.luck@intel.com> Cc: "Xiaochen Shen" <xiaochen.shen@intel.com> Link: https://lkml.kernel.org/r/20180904174614.26682-1-yu.c.chen@intel.com Link: https://lkml.kernel.org/r/1537048707-76280-3-git-send-email-fenghua.yu@intel.com
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/kernel/cpu/intel_rdt_rdtgroup.c14
1 files changed, 10 insertions, 4 deletions
diff --git a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
index b799c00bef09..32e8bbdf2400 100644
--- a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
+++ b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
@@ -1155,8 +1155,8 @@ static int rdtgroup_size_show(struct kernfs_open_file *of,
struct rdt_resource *r;
struct rdt_domain *d;
unsigned int size;
- bool sep = false;
- u32 cbm;
+ bool sep;
+ u32 ctrl;
rdtgrp = rdtgroup_kn_lock_live(of->kn);
if (!rdtgrp) {
@@ -1174,6 +1174,7 @@ static int rdtgroup_size_show(struct kernfs_open_file *of,
}
for_each_alloc_enabled_rdt_resource(r) {
+ sep = false;
seq_printf(s, "%*s:", max_name_width, r->name);
list_for_each_entry(d, &r->domains, list) {
if (sep)
@@ -1181,8 +1182,13 @@ static int rdtgroup_size_show(struct kernfs_open_file *of,
if (rdtgrp->mode == RDT_MODE_PSEUDO_LOCKSETUP) {
size = 0;
} else {
- cbm = d->ctrl_val[rdtgrp->closid];
- size = rdtgroup_cbm_to_size(r, d, cbm);
+ ctrl = (!is_mba_sc(r) ?
+ d->ctrl_val[rdtgrp->closid] :
+ d->mbps_val[rdtgrp->closid]);
+ if (r->rid == RDT_RESOURCE_MBA)
+ size = ctrl;
+ else
+ size = rdtgroup_cbm_to_size(r, d, ctrl);
}
seq_printf(s, "%d=%u", d->id, size);
sep = true;