linux-kernel - [PATCH 5.1 121/121] x86/resctrl: Dont stop walking closids when a locksetup group is found

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Date:   Mon, 24 Jun 2019 17:57:33 +0800
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, James Morse <james.morse@....com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Reinette Chatre <reinette.chatre@...el.com>,
        Fenghua Yu <fenghua.yu@...el.com>,
        Borislav Petkov <bp@...en8.de>, H Peter Avin <hpa@...or.com>
Subject: [PATCH 5.1 121/121] x86/resctrl: Dont stop walking closids when a locksetup group is found

From: James Morse <james.morse@....com>

commit 87d3aa28f345bea77c396855fa5d5fec4c24461f upstream.

When a new control group is created __init_one_rdt_domain() walks all
the other closids to calculate the sets of used and unused bits.

If it discovers a pseudo_locksetup group, it breaks out of the loop.  This
means any later closid doesn't get its used bits added to used_b.  These
bits will then get set in unused_b, and added to the new control group's
configuration, even if they were marked as exclusive for a later closid.

When encountering a pseudo_locksetup group, we should continue. This is
because "a resource group enters 'pseudo-locked' mode after the schemata is
written while the resource group is in 'pseudo-locksetup' mode." When we
find a pseudo_locksetup group, its configuration is expected to be
overwritten, we can skip it.

Fixes: dfe9674b04ff6 ("x86/intel_rdt: Enable entering of pseudo-locksetup mode")
Signed-off-by: James Morse <james.morse@....com>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Acked-by: Reinette Chatre <reinette.chatre@...el.com>
Cc: Fenghua Yu <fenghua.yu@...el.com>
Cc: Borislav Petkov <bp@...en8.de>
Cc: H Peter Avin <hpa@...or.com>
Cc: <stable@...r.kernel.org>
Link: https://lkml.kernel.org/r/20190603172531.178830-1-james.morse@arm.com
[Dropped comment due to lack of space]
Signed-off-by: James Morse <james.morse@....com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 arch/x86/kernel/cpu/resctrl/rdtgroup.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -2556,7 +2556,7 @@ static int rdtgroup_init_alloc(struct rd
 				if (closid_allocated(i) && i != closid) {
 					mode = rdtgroup_mode_by_closid(i);
 					if (mode == RDT_MODE_PSEUDO_LOCKSETUP)
-						break;
+						continue;
 					/*
 					 * If CDP is active include peer
 					 * domain's usage to ensure there