ppc: fix exception model for HV mode

This properly implements LPES0 handling for HV vs. !HV mode and
removes the unsupported LPES1. This has been removed from the specs
since ISA v2.07.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
[clg: AIL implementation was fixed in commit 5c94b2a5e5ef. This patch
      only contains the bits of the original patch related to LPES0
      handling, adapted commit log.
      fixed checkpatch.pl errors. ]
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

1 files changed, 45 insertions, 89 deletions

diff --git a/target-ppc/excp_helper.c b/target-ppc/excp_helper.c
index aa0b63f4b0..7c44c102db 100644
--- a/target-ppc/excp_helper.c
+++ b/target-ppc/excp_helper.c
@@ -77,18 +77,8 @@ static inline void powerpc_excp(PowerPCCPU *cpu, int excp_model, int excp)
     CPUState *cs = CPU(cpu);
     CPUPPCState *env = &cpu->env;
     target_ulong msr, new_msr, vector;
-    int srr0, srr1, asrr0, asrr1;
-    int lpes0, lpes1, lev, ail;
-
-    if (0) {
-        /* XXX: find a suitable condition to enable the hypervisor mode */
-        lpes0 = (env->spr[SPR_LPCR] >> 1) & 1;
-        lpes1 = (env->spr[SPR_LPCR] >> 2) & 1;
-    } else {
-        /* Those values ensure we won't enter the hypervisor mode */
-        lpes0 = 0;
-        lpes1 = 1;
-    }
+    int srr0, srr1, asrr0, asrr1, lev, ail;
+    bool lpes0;
 
     qemu_log_mask(CPU_LOG_INT, "Raise exception at " TARGET_FMT_lx
                   " => %08x (%02x)\n", env->nip, excp, env->error_code);
@@ -100,8 +90,10 @@ static inline void powerpc_excp(PowerPCCPU *cpu, int excp_model, int excp)
         msr = env->msr & ~0x783f0000ULL;
     }
 
-    /* new interrupt handler msr */
-    new_msr = env->msr & ((target_ulong)1 << MSR_ME);
+    /* new interrupt handler msr preserves existing HV and ME unless
+     * explicitly overriden
+     */
+    new_msr = env->msr & (((target_ulong)1 << MSR_ME) | MSR_HVB);
 
     /* target registers */
     srr0 = SPR_SRR0;
@@ -111,12 +103,19 @@ static inline void powerpc_excp(PowerPCCPU *cpu, int excp_model, int excp)
 
     /* Exception targetting modifiers
      *
+     * LPES0 is supported on POWER7/8
+     * LPES1 is not supported (old iSeries mode)
+     *
+     * On anything else, we behave as if LPES0 is 1
+     * (externals don't alter MSR:HV)
+     *
      * AIL is initialized here but can be cleared by
      * selected exceptions
      */
 #if defined(TARGET_PPC64)
     if (excp_model == POWERPC_EXCP_POWER7 ||
         excp_model == POWERPC_EXCP_POWER8) {
+        lpes0 = !!(env->spr[SPR_LPCR] & LPCR_LPES0);
         if (excp_model == POWERPC_EXCP_POWER8) {
             ail = (env->spr[SPR_LPCR] & LPCR_AIL) >> LPCR_AIL_SHIFT;
         } else {
@@ -125,6 +124,7 @@ static inline void powerpc_excp(PowerPCCPU *cpu, int excp_model, int excp)
     } else
 #endif /* defined(TARGET_PPC64) */
     {
+        lpes0 = true;
         ail = 0;
     }
 
@@ -162,10 +162,7 @@ static inline void powerpc_excp(PowerPCCPU *cpu, int excp_model, int excp)
             cs->halted = 1;
             cs->interrupt_request |= CPU_INTERRUPT_EXITTB;
         }
-        if (0) {
-            /* XXX: find a suitable condition to enable the hypervisor mode */
-            new_msr |= (target_ulong)MSR_HVB;
-        }
+        new_msr |= (target_ulong)MSR_HVB;
         ail = 0;
 
         /* machine check exceptions don't have ME set */
@@ -191,23 +188,20 @@ static inline void powerpc_excp(PowerPCCPU *cpu, int excp_model, int excp)
     case POWERPC_EXCP_DSI:       /* Data storage exception                   */
         LOG_EXCP("DSI exception: DSISR=" TARGET_FMT_lx" DAR=" TARGET_FMT_lx
                  "\n", env->spr[SPR_DSISR], env->spr[SPR_DAR]);
-        if (lpes1 == 0) {
-            new_msr |= (target_ulong)MSR_HVB;
-        }
         goto store_next;
     case POWERPC_EXCP_ISI:       /* Instruction storage exception            */
         LOG_EXCP("ISI exception: msr=" TARGET_FMT_lx ", nip=" TARGET_FMT_lx
                  "\n", msr, env->nip);
-        if (lpes1 == 0) {
-            new_msr |= (target_ulong)MSR_HVB;
-        }
         msr |= env->error_code;
         goto store_next;
     case POWERPC_EXCP_EXTERNAL:  /* External input                           */
         cs = CPU(cpu);
 
-        if (lpes0 == 1) {
+        if (!lpes0) {
             new_msr |= (target_ulong)MSR_HVB;
+            new_msr |= env->msr & ((target_ulong)1 << MSR_RI);
+            srr0 = SPR_HSRR0;
+            srr1 = SPR_HSRR1;
         }
         if (env->mpic_proxy) {
             /* IACK the IRQ on delivery */
@@ -215,9 +209,6 @@ static inline void powerpc_excp(PowerPCCPU *cpu, int excp_model, int excp)
         }
         goto store_next;
     case POWERPC_EXCP_ALIGN:     /* Alignment exception                      */
-        if (lpes1 == 0) {
-            new_msr |= (target_ulong)MSR_HVB;
-        }
         /* XXX: this is false */
         /* Get rS/rD and rA from faulting opcode */
         env->spr[SPR_DSISR] |= (cpu_ldl_code(env, (env->nip - 4))
@@ -232,9 +223,6 @@ static inline void powerpc_excp(PowerPCCPU *cpu, int excp_model, int excp)
                 env->error_code = 0;
                 return;
             }
-            if (lpes1 == 0) {
-                new_msr |= (target_ulong)MSR_HVB;
-            }
             msr |= 0x00100000;
             if (msr_fe0 == msr_fe1) {
                 goto store_next;
@@ -243,23 +231,14 @@ static inline void powerpc_excp(PowerPCCPU *cpu, int excp_model, int excp)
             break;
         case POWERPC_EXCP_INVAL:
             LOG_EXCP("Invalid instruction at " TARGET_FMT_lx "\n", env->nip);
-            if (lpes1 == 0) {
-                new_msr |= (target_ulong)MSR_HVB;
-            }
             msr |= 0x00080000;
             env->spr[SPR_BOOKE_ESR] = ESR_PIL;
             break;
         case POWERPC_EXCP_PRIV:
-            if (lpes1 == 0) {
-                new_msr |= (target_ulong)MSR_HVB;
-            }
             msr |= 0x00040000;
             env->spr[SPR_BOOKE_ESR] = ESR_PPR;
             break;
         case POWERPC_EXCP_TRAP:
-            if (lpes1 == 0) {
-                new_msr |= (target_ulong)MSR_HVB;
-            }
             msr |= 0x00020000;
             env->spr[SPR_BOOKE_ESR] = ESR_PTR;
             break;
@@ -271,27 +250,23 @@ static inline void powerpc_excp(PowerPCCPU *cpu, int excp_model, int excp)
         }
         goto store_current;
     case POWERPC_EXCP_FPU:       /* Floating-point unavailable exception     */
-        if (lpes1 == 0) {
-            new_msr |= (target_ulong)MSR_HVB;
-        }
         goto store_current;
     case POWERPC_EXCP_SYSCALL:   /* System call exception                    */
         dump_syscall(env);
         lev = env->error_code;
+
+        /* "PAPR mode" built-in hypercall emulation */
         if ((lev == 1) && cpu_ppc_hypercall) {
             cpu_ppc_hypercall(cpu);
             return;
         }
-        if (lev == 1 || (lpes0 == 0 && lpes1 == 0)) {
+        if (lev == 1) {
             new_msr |= (target_ulong)MSR_HVB;
         }
         goto store_next;
     case POWERPC_EXCP_APU:       /* Auxiliary processor unavailable          */
         goto store_current;
     case POWERPC_EXCP_DECR:      /* Decrementer exception                    */
-        if (lpes1 == 0) {
-            new_msr |= (target_ulong)MSR_HVB;
-        }
         goto store_next;
     case POWERPC_EXCP_FIT:       /* Fixed-interval timer interrupt           */
         /* FIT on 4xx */
@@ -361,21 +336,12 @@ static inline void powerpc_excp(PowerPCCPU *cpu, int excp_model, int excp)
             new_msr &= ~((target_ulong)1 << MSR_ME);
         }
 
-        if (0) {
-            /* XXX: find a suitable condition to enable the hypervisor mode */
-            new_msr |= (target_ulong)MSR_HVB;
-        }
+        new_msr |= (target_ulong)MSR_HVB;
         ail = 0;
         goto store_next;
     case POWERPC_EXCP_DSEG:      /* Data segment exception                   */
-        if (lpes1 == 0) {
-            new_msr |= (target_ulong)MSR_HVB;
-        }
         goto store_next;
     case POWERPC_EXCP_ISEG:      /* Instruction segment exception            */
-        if (lpes1 == 0) {
-            new_msr |= (target_ulong)MSR_HVB;
-        }
         goto store_next;
     case POWERPC_EXCP_HDECR:     /* Hypervisor decrementer exception         */
         srr0 = SPR_HSRR0;
@@ -384,9 +350,6 @@ static inline void powerpc_excp(PowerPCCPU *cpu, int excp_model, int excp)
         new_msr |= env->msr & ((target_ulong)1 << MSR_RI);
         goto store_next;
     case POWERPC_EXCP_TRACE:     /* Trace exception                          */
-        if (lpes1 == 0) {
-            new_msr |= (target_ulong)MSR_HVB;
-        }
         goto store_next;
     case POWERPC_EXCP_HDSI:      /* Hypervisor data storage exception        */
         srr0 = SPR_HSRR0;
@@ -413,19 +376,10 @@ static inline void powerpc_excp(PowerPCCPU *cpu, int excp_model, int excp)
         new_msr |= env->msr & ((target_ulong)1 << MSR_RI);
         goto store_next;
     case POWERPC_EXCP_VPU:       /* Vector unavailable exception             */
-        if (lpes1 == 0) {
-            new_msr |= (target_ulong)MSR_HVB;
-        }
         goto store_current;
     case POWERPC_EXCP_VSXU:       /* VSX unavailable exception               */
-        if (lpes1 == 0) {
-            new_msr |= (target_ulong)MSR_HVB;
-        }
         goto store_current;
     case POWERPC_EXCP_FU:         /* Facility unavailable exception          */
-        if (lpes1 == 0) {
-            new_msr |= (target_ulong)MSR_HVB;
-        }
         goto store_current;
     case POWERPC_EXCP_PIT:       /* Programmable interval timer interrupt    */
         LOG_EXCP("PIT exception\n");
@@ -444,9 +398,6 @@ static inline void powerpc_excp(PowerPCCPU *cpu, int excp_model, int excp)
                   "is not implemented yet !\n");
         goto store_next;
     case POWERPC_EXCP_IFTLB:     /* Instruction fetch TLB error              */
-        if (lpes1 == 0) { /* XXX: check this */
-            new_msr |= (target_ulong)MSR_HVB;
-        }
         switch (excp_model) {
         case POWERPC_EXCP_602:
         case POWERPC_EXCP_603:
@@ -463,9 +414,6 @@ static inline void powerpc_excp(PowerPCCPU *cpu, int excp_model, int excp)
         }
         break;
     case POWERPC_EXCP_DLTLB:     /* Data load TLB miss                       */
-        if (lpes1 == 0) { /* XXX: check this */
-            new_msr |= (target_ulong)MSR_HVB;
-        }
         switch (excp_model) {
         case POWERPC_EXCP_602:
         case POWERPC_EXCP_603:
@@ -482,9 +430,6 @@ static inline void powerpc_excp(PowerPCCPU *cpu, int excp_model, int excp)
         }
         break;
     case POWERPC_EXCP_DSTLB:     /* Data store TLB miss                      */
-        if (lpes1 == 0) { /* XXX: check this */
-            new_msr |= (target_ulong)MSR_HVB;
-        }
         switch (excp_model) {
         case POWERPC_EXCP_602:
         case POWERPC_EXCP_603:
@@ -590,9 +535,6 @@ static inline void powerpc_excp(PowerPCCPU *cpu, int excp_model, int excp)
                   "is not implemented yet !\n");
         goto store_next;
     case POWERPC_EXCP_PERFM:     /* Embedded performance monitor interrupt   */
-        if (lpes1 == 0) {
-            new_msr |= (target_ulong)MSR_HVB;
-        }
         /* XXX: TODO */
         cpu_abort(cs,
                   "Performance counter exception is not implemented yet !\n");
@@ -636,6 +578,13 @@ static inline void powerpc_excp(PowerPCCPU *cpu, int excp_model, int excp)
     }
     /* Save MSR */
     env->spr[srr1] = msr;
+
+    /* Sanity check */
+    if (!(env->msr_mask & MSR_HVB) && (srr0 == SPR_HSRR0)) {
+        cpu_abort(cs, "Trying to deliver HV exception %d with "
+                  "no HV support\n", excp);
+    }
+
     /* If any alternate SRR register are defined, duplicate saved values */
     if (asrr0 != -1) {
         env->spr[asrr0] = env->spr[srr0];
@@ -644,14 +593,20 @@ static inline void powerpc_excp(PowerPCCPU *cpu, int excp_model, int excp)
         env->spr[asrr1] = env->spr[srr1];
     }
 
-    if (env->spr[SPR_LPCR] & LPCR_AIL) {
-        new_msr |= (1 << MSR_IR) | (1 << MSR_DR);
-    }
-
+    /* Sort out endianness of interrupt, this differs depending on the
+     * CPU, the HV mode, etc...
+     */
 #ifdef TARGET_PPC64
-    if (excp_model == POWERPC_EXCP_POWER7 ||
-        excp_model == POWERPC_EXCP_POWER8) {
-        if (env->spr[SPR_LPCR] & LPCR_ILE) {
+    if (excp_model == POWERPC_EXCP_POWER7) {
+        if (!(new_msr & MSR_HVB) && (env->spr[SPR_LPCR] & LPCR_ILE)) {
+            new_msr |= (target_ulong)1 << MSR_LE;
+        }
+    } else if (excp_model == POWERPC_EXCP_POWER8) {
+        if (new_msr & MSR_HVB) {
+            if (env->spr[SPR_HID0] & HID0_HILE) {
+                new_msr |= (target_ulong)1 << MSR_LE;
+            }
+        } else if (env->spr[SPR_LPCR] & LPCR_ILE) {
             new_msr |= (target_ulong)1 << MSR_LE;
         }
     } else if (msr_ile) {
@@ -674,7 +629,8 @@ static inline void powerpc_excp(PowerPCCPU *cpu, int excp_model, int excp)
     /* AIL only works if there is no HV transition and we are running with
      * translations enabled
      */
-    if (!((msr >> MSR_IR) & 1) || !((msr >> MSR_DR) & 1)) {
+    if (!((msr >> MSR_IR) & 1) || !((msr >> MSR_DR) & 1) ||
+        ((new_msr & MSR_HVB) && !(msr & MSR_HVB))) {
         ail = 0;
     }
     /* Handle AIL */