From 50b5e30e8111f88029dd0f6e922251f1839a1044 Mon Sep 17 00:00:00 2001 From: Thomas Huth Date: Wed, 21 Sep 2016 15:06:45 +0200 Subject: [PATCH] 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 Signed-off-by: Paul Mackerras Signed-off-by: Jiri Slaby --- arch/powerpc/include/asm/reg.h | 1 + arch/powerpc/kvm/book3s_emulate.c | 2 ++ 2 files changed, 3 insertions(+) diff --git a/arch/powerpc/include/asm/reg.h b/arch/powerpc/include/asm/reg.h index 53762dbf547c1..3c612f658988d 100644 --- a/arch/powerpc/include/asm/reg.h +++ b/arch/powerpc/include/asm/reg.h @@ -648,6 +648,7 @@ #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 cda2cba569156..5d509ee394651 100644 --- a/arch/powerpc/kvm/book3s_emulate.c +++ b/arch/powerpc/kvm/book3s_emulate.c @@ -465,6 +465,7 @@ int kvmppc_core_emulate_mtspr(struct kvm_vcpu *vcpu, int sprn, ulong spr_val) case SPRN_MMCR0: case SPRN_MMCR1: case SPRN_MMCR2: + case SPRN_UMMCR2: #endif break; unprivileged: @@ -570,6 +571,7 @@ int kvmppc_core_emulate_mfspr(struct kvm_vcpu *vcpu, int sprn, ulong *spr_val) case SPRN_MMCR0: case SPRN_MMCR1: case SPRN_MMCR2: + case SPRN_UMMCR2: case SPRN_TIR: #endif *spr_val = 0;