[tip:x86/urgent] x86/intel_rdt: Do not allow pseudo-locking of MBA resource

[tip-bot for Reinette Chatre]

Commit-ID:  32d736abed4febff4b6bf85d5d240ee24d254322
Gitweb:     https://git.kernel.org/tip/32d736abed4febff4b6bf85d5d240ee24d254322
Author:     Reinette Chatre <reinette.chatre@xxxxxxxxx>
AuthorDate: Sat, 15 Sep 2018 14:58:24 -0700
Committer:  Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitDate: Tue, 18 Sep 2018 23:38:06 +0200

x86/intel_rdt: Do not allow pseudo-locking of MBA resource

A system supporting pseudo-locking may have MBA as well as CAT
resources of which only the CAT resources could support cache
pseudo-locking. When the schemata to be pseudo-locked is provided it
should be checked that that schemata does not attempt to pseudo-lock a
MBA resource.

Fixes: e0bdfe8e3 ("x86/intel_rdt: Support creation/removal of pseudo-locked region")
Signed-off-by: Reinette Chatre <reinette.chatre@xxxxxxxxx>
Signed-off-by: Fenghua Yu <fenghua.yu@xxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: "H Peter Anvin" <hpa@xxxxxxxxx>
Cc: "Tony Luck" <tony.luck@xxxxxxxxx>
Cc: "Xiaochen Shen" <xiaochen.shen@xxxxxxxxx>
Cc: "Chen Yu" <yu.c.chen@xxxxxxxxx>
Link: https://lkml.kernel.org/r/1537048707-76280-7-git-send-email-fenghua.yu@xxxxxxxxx

---
 arch/x86/kernel/cpu/intel_rdt_ctrlmondata.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/arch/x86/kernel/cpu/intel_rdt_ctrlmondata.c b/arch/x86/kernel/cpu/intel_rdt_ctrlmondata.c
index edd5761f7336..0f53049719cd 100644
--- a/arch/x86/kernel/cpu/intel_rdt_ctrlmondata.c
+++ b/arch/x86/kernel/cpu/intel_rdt_ctrlmondata.c
@@ -195,6 +195,12 @@ static int parse_line(char *line, struct rdt_resource *r,
 	struct rdt_domain *d;
 	unsigned long dom_id;
 
+	if (rdtgrp->mode == RDT_MODE_PSEUDO_LOCKSETUP &&
+	    r->rid == RDT_RESOURCE_MBA) {
+		rdt_last_cmd_puts("Cannot pseudo-lock MBA resource\n");
+		return -EINVAL;
+	}
+
 next:
 	if (!line || line[0] == '\0')
 		return 0;