KVM: PPC: Book3S HV: Implement architecture compatibility modes for POWER8

This allows us to select architecture 2.05 (POWER6) or 2.06 (POWER7)
compatibility modes on a POWER8 processor.  (Note that transactional
memory is disabled for usermode if either or both of the PCR_TM_DIS
and PCR_ARCH_206 bits are set.)

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>

2 files changed, 17 insertions, 1 deletions

diff --git a/arch/powerpc/include/asm/reg.h b/arch/powerpc/include/asm/reg.h
index 2f41e6475648..5a9983147683 100644
--- a/arch/powerpc/include/asm/reg.h
+++ b/arch/powerpc/include/asm/reg.h
@@ -329,6 +329,8 @@
 #define SPRN_PCR        0x152   /* Processor compatibility register */
 #define   PCR_VEC_DIS   (1ul << (63-0)) /* Vec. disable (bit NA since POWER8) */
 #define   PCR_VSX_DIS   (1ul << (63-1)) /* VSX disable (bit NA since POWER8) */
+#define   PCR_TM_DIS    (1ul << (63-2)) /* Trans. memory disable (POWER8) */
+#define   PCR_ARCH_206  0x4             /* Architecture 2.06 */
 #define   PCR_ARCH_205  0x2             /* Architecture 2.05 */
 #define SPRN_HEIR       0x153   /* Hypervisor Emulated Instruction Register */
 #define SPRN_TLBINDEXR  0x154   /* P7 TLB control register */
diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 1bf681e8a05f..1e9f4b45432b 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -184,14 +184,28 @@ int kvmppc_set_arch_compat(struct kvm_vcpu *vcpu, u32 arch_compat)
 
                 switch (arch_compat) {
                 case PVR_ARCH_205:
-                        pcr = PCR_ARCH_205;
+                        /*
+                         * If an arch bit is set in PCR, all the defined
+                         * higher-order arch bits also have to be set.
+                         */
+                        pcr = PCR_ARCH_206 | PCR_ARCH_205;
                         break;
                 case PVR_ARCH_206:
                 case PVR_ARCH_206p:
+                        pcr = PCR_ARCH_206;
+                        break;
+                case PVR_ARCH_207:
                         break;
                 default:
                         return -EINVAL;
                 }
+
+                if (!cpu_has_feature(CPU_FTR_ARCH_207S)) {
+                        /* POWER7 can't emulate POWER8 */
+                        if (!(pcr & PCR_ARCH_206))
+                                return -EINVAL;
+                        pcr &= ~PCR_ARCH_206;
+                }
         }
 
         spin_lock(&vc->lock);