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authorThomas Huth <thuth@redhat.com>2016-09-21 15:06:45 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2016-10-16 17:36:14 +0200
commit418fdccd410e34e358368b5439a20dd08d75c3c2 (patch)
parent5a4a45686a87f29aadf462c605df5f9361b56310 (diff)
KVM: PPC: Book3s PR: Allow access to unprivileged MMCR2 register
commit fa73c3b25bd8d0d393dc6109a1dba3c2aef0451e upstream. The MMCR2 register is available twice, one time with number 785 (privileged access), and one time with number 769 (unprivileged, but it can be disabled completely). In former times, the Linux kernel was using the unprivileged register 769 only, but since commit 8dd75ccb571f3c92c ("powerpc: Use privileged SPR number for MMCR2"), it uses the privileged register 785 instead. The KVM-PR code then of course also switched to use the SPR 785, but this is causing older guest kernels to crash, since these kernels still access 769 instead. So to support older kernels with KVM-PR again, we have to support register 769 in KVM-PR, too. Fixes: 8dd75ccb571f3c92c48014b3dabd3d51a115ab41 Signed-off-by: Thomas Huth <thuth@redhat.com> Signed-off-by: Paul Mackerras <paulus@ozlabs.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2 files changed, 3 insertions, 0 deletions
diff --git a/arch/powerpc/include/asm/reg.h b/arch/powerpc/include/asm/reg.h
index 070fa8552051..627d129d7fcb 100644
--- a/arch/powerpc/include/asm/reg.h
+++ b/arch/powerpc/include/asm/reg.h
@@ -708,6 +708,7 @@
#define MMCR0_FCHV 0x00000001UL /* freeze conditions in hypervisor mode */
#define SPRN_MMCR1 798
#define SPRN_MMCR2 785
+#define SPRN_UMMCR2 769
#define SPRN_MMCRA 0x312
#define MMCRA_SDSYNC 0x80000000UL /* SDAR synced with SIAR */
#define MMCRA_SDAR_DCACHE_MISS 0x40000000UL
diff --git a/arch/powerpc/kvm/book3s_emulate.c b/arch/powerpc/kvm/book3s_emulate.c
index 2afdb9c0937d..729f8faa95c5 100644
--- a/arch/powerpc/kvm/book3s_emulate.c
+++ b/arch/powerpc/kvm/book3s_emulate.c
@@ -498,6 +498,7 @@ int kvmppc_core_emulate_mtspr_pr(struct kvm_vcpu *vcpu, int sprn, ulong spr_val)
case SPRN_MMCR0:
case SPRN_MMCR1:
case SPRN_MMCR2:
+ case SPRN_UMMCR2:
@@ -640,6 +641,7 @@ int kvmppc_core_emulate_mfspr_pr(struct kvm_vcpu *vcpu, int sprn, ulong *spr_val
case SPRN_MMCR0:
case SPRN_MMCR1:
case SPRN_MMCR2:
+ case SPRN_UMMCR2:
case SPRN_TIR:
*spr_val = 0;