[tip: x86/urgent] x86/resctrl: Preserve CDP enable over CPU hotplug

From: tip-bot2 for James Morse
Date: Fri Apr 17 2020 - 13:46:01 EST


The following commit has been merged into the x86/urgent branch of tip:

Commit-ID: 9fe0450785abbc04b0ed5d3cf61fcdb8ab656b4b
Gitweb: https://git.kernel.org/tip/9fe0450785abbc04b0ed5d3cf61fcdb8ab656b4b
Author: James Morse <james.morse@xxxxxxx>
AuthorDate: Fri, 21 Feb 2020 16:21:05
Committer: Borislav Petkov <bp@xxxxxxx>
CommitterDate: Fri, 17 Apr 2020 19:35:01 +02:00

x86/resctrl: Preserve CDP enable over CPU hotplug

Resctrl assumes that all CPUs are online when the filesystem is mounted,
and that CPUs remember their CDP-enabled state over CPU hotplug.

This goes wrong when resctrl's CDP-enabled state changes while all the
CPUs in a domain are offline.

When a domain comes online, enable (or disable!) CDP to match resctrl's
current setting.

Fixes: 5ff193fbde20 ("x86/intel_rdt: Add basic resctrl filesystem support")
Suggested-by: Reinette Chatre <reinette.chatre@xxxxxxxxx>
Signed-off-by: James Morse <james.morse@xxxxxxx>
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Link: https://lkml.kernel.org/r/20200221162105.154163-1-james.morse@xxxxxxx
---
arch/x86/kernel/cpu/resctrl/core.c | 2 ++
arch/x86/kernel/cpu/resctrl/internal.h | 1 +
arch/x86/kernel/cpu/resctrl/rdtgroup.c | 13 +++++++++++++
3 files changed, 16 insertions(+)

diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c
index 89049b3..d8cc522 100644
--- a/arch/x86/kernel/cpu/resctrl/core.c
+++ b/arch/x86/kernel/cpu/resctrl/core.c
@@ -578,6 +578,8 @@ static void domain_add_cpu(int cpu, struct rdt_resource *r)
d->id = id;
cpumask_set_cpu(cpu, &d->cpu_mask);

+ rdt_domain_reconfigure_cdp(r);
+
if (r->alloc_capable && domain_setup_ctrlval(r, d)) {
kfree(d);
return;
diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
index 181c992..3dd13f3 100644
--- a/arch/x86/kernel/cpu/resctrl/internal.h
+++ b/arch/x86/kernel/cpu/resctrl/internal.h
@@ -601,5 +601,6 @@ bool has_busy_rmid(struct rdt_resource *r, struct rdt_domain *d);
void __check_limbo(struct rdt_domain *d, bool force_free);
bool cbm_validate_intel(char *buf, u32 *data, struct rdt_resource *r);
bool cbm_validate_amd(char *buf, u32 *data, struct rdt_resource *r);
+void rdt_domain_reconfigure_cdp(struct rdt_resource *r);

#endif /* _ASM_X86_RESCTRL_INTERNAL_H */
diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index 9d4e73a..5a359d9 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -1859,6 +1859,19 @@ static int set_cache_qos_cfg(int level, bool enable)
return 0;
}

+/* Restore the qos cfg state when a domain comes online */
+void rdt_domain_reconfigure_cdp(struct rdt_resource *r)
+{
+ if (!r->alloc_capable)
+ return;
+
+ if (r == &rdt_resources_all[RDT_RESOURCE_L2DATA])
+ l2_qos_cfg_update(&r->alloc_enabled);
+
+ if (r == &rdt_resources_all[RDT_RESOURCE_L3DATA])
+ l3_qos_cfg_update(&r->alloc_enabled);
+}
+
/*
* Enable or disable the MBA software controller
* which helps user specify bandwidth in MBps.