[v2,03/10] ppc: fix exception model for HV mode

From: Benjamin Herrenschmidt <benh@kernel.crashing.org>

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>
---
 target-ppc/excp_helper.c | 134 ++++++++++++++++-------------------------------
 1 file changed, 45 insertions(+), 89 deletions(-)

On Tue, Jun 21, 2016 at 11:48:48PM +0200, Cédric Le Goater wrote:
> From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> 
> 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>

Reviewed-by: David Gibson <david@gibson.dropbear.id.au>

> ---
>  target-ppc/excp_helper.c | 134 ++++++++++++++++-------------------------------
>  1 file changed, 45 insertions(+), 89 deletions(-)
> 
> diff --git a/target-ppc/excp_helper.c b/target-ppc/excp_helper.c
> index aa0b63f4b0de..7c44c102db39 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 */