From: Marc Zyngier <marc.zyngier@arm.com>
Date: Mon, 23 Mar 2015 07:03:28 +0000 (+0800)
Subject: ARM: KVM: Fix MPIDR computing to support virtual clusters
X-Git-Tag: v3.12.42~60
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=3925ae28c4489b87dc4a515716172c1a3a1d2363;p=thirdparty%2Fkernel%2Fstable.git

ARM: KVM: Fix MPIDR computing to support virtual clusters

commit 2d1d841bd44e24b58a3d3cc4fa793670aaa38fbf upstream.

In order to be able to support more than 4 A7 or A15 CPUs,
we need to fix the MPIDR computing to reflect the fact that
both A15 and A7 can only exist in clusters of at most 4 CPUs.

Fix the MPIDR computing to allow virtual clusters to be exposed
to the guest.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---

diff --git a/arch/arm/kvm/coproc_a15.c b/arch/arm/kvm/coproc_a15.c
index bbd4b888dbf3a..8611c5c45d938 100644
--- a/arch/arm/kvm/coproc_a15.c
+++ b/arch/arm/kvm/coproc_a15.c
@@ -27,11 +27,13 @@
 static void reset_mpidr(struct kvm_vcpu *vcpu, const struct coproc_reg *r)
 {
 	/*
-	 * Compute guest MPIDR. No need to mess around with different clusters
-	 * but we read the 'U' bit from the underlying hardware directly.
+	 * Compute guest MPIDR. We build a virtual cluster out of the
+	 * vcpu_id, but we read the 'U' bit from the underlying
+	 * hardware directly.
 	 */
-	vcpu->arch.cp15[c0_MPIDR] = (read_cpuid_mpidr() & MPIDR_SMP_BITMASK)
-					| vcpu->vcpu_id;
+	vcpu->arch.cp15[c0_MPIDR] = ((read_cpuid_mpidr() & MPIDR_SMP_BITMASK) |
+				   ((vcpu->vcpu_id >> 2) << MPIDR_LEVEL_BITS) |
+				   (vcpu->vcpu_id & 3));
 }
 
 #include "coproc.h"