linux-kernel - [PATCH 1/3] x86/intel_rdt/cqm: Add fix to clear the default RMID during hotcpu

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Date:   Wed,  9 Aug 2017 11:46:33 -0700
From:   Vikas Shivappa <vikas.shivappa@...ux.intel.com>
To:     vikas.shivappa@...el.com
Cc:     vikas.shivappa@...ux.intel.com, x86@...nel.org,
        linux-kernel@...r.kernel.org, hpa@...or.com, tglx@...utronix.de,
        peterz@...radead.org, ravi.v.shankar@...el.com,
        tony.luck@...el.com, fenghua.yu@...el.com, eranian@...gle.com,
        davidcc@...gle.com, ak@...ux.intel.com,
        sai.praneeth.prakhya@...el.com
Subject: [PATCH 1/3] x86/intel_rdt/cqm: Add fix to clear the default RMID during hotcpu

The user configured per cpu default RMID is not cleared during cpu
hotplug. This may lead to incorrect RMID values after a cpu goes offline
and again comes back online. Clear the per cpu default RMID during cpu
offline and online handling.

Reported-by: Prakyha Sai Praneeth <sai.praneeth.prakhya@...el.com>
Signed-off-by: Vikas Shivappa <vikas.shivappa@...ux.intel.com>
---
 arch/x86/kernel/cpu/intel_rdt.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/x86/kernel/cpu/intel_rdt.c b/arch/x86/kernel/cpu/intel_rdt.c
index da4f389..4b9edb2 100644
--- a/arch/x86/kernel/cpu/intel_rdt.c
+++ b/arch/x86/kernel/cpu/intel_rdt.c
@@ -551,6 +551,7 @@ static void clear_closid_rmid(int cpu)
 	struct intel_pqr_state *state = this_cpu_ptr(&pqr_state);
 
 	per_cpu(rdt_cpu_default.closid, cpu) = 0;
+	per_cpu(rdt_cpu_default.rmid, cpu) = 0;
 	state->closid = 0;
 	state->rmid = 0;
 	wrmsr(IA32_PQR_ASSOC, 0, 0);
-- 
1.9.1