Re: [Qemu-ppc] [PATCH v3 09/12] target/ppc: Implement H_REGISTER_PROCESS_TABLE H_CALL

[Sam Bobroff]

On Fri, Mar 03, 2017 at 03:09:05PM +1100, David Gibson wrote:
> On Thu, Mar 02, 2017 at 04:39:04PM +1100, Sam Bobroff wrote:
> > From: Suraj Jitindar Singh <address@hidden>
> > 
> > The H_REGISTER_PROCESS_TABLE H_CALL is used by a guest to indicate to the
> > hypervisor where in memory its process table is and how translation should
> > be performed using this process table.
> > 
> > Provide the implementation of this H_CALL for a guest.
> > 
> > We first check for invalid flags, then parse the flags to determine the
> > operation, and then check the other parameters for valid values based on
> > the operation (register new table/deregister table/maintain registration).
> > The process table is then stored in the appropriate location and registered
> > with the hypervisor (if running under KVM), and the LPCR_[UPRT/GTSE] bits
> > are updated as required.
> > 
> > Signed-off-by: Suraj Jitindar Singh <address@hidden>
> > Signed-off-by: Sam Bobroff <address@hidden>
> > ---
> > Changes in v3:
> > * KVM-only implementation of h_register_process_table() integrated into the 
> > TCG version.
> > 
> >  hw/ppc/spapr.c         |  11 ++++-
> >  hw/ppc/spapr_hcall.c   | 114 
> > +++++++++++++++++++++++++++++++++++++++++++++++--
> >  include/hw/ppc/spapr.h |   1 +
> >  target/ppc/kvm.c       |  18 ++++++++
> >  target/ppc/kvm_ppc.h   |   2 +
> >  5 files changed, 141 insertions(+), 5 deletions(-)
> > 
> > diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> > index 0b266e96f1..8cbab04101 100644
> > --- a/hw/ppc/spapr.c
> > +++ b/hw/ppc/spapr.c
> > @@ -40,6 +40,7 @@
> >  #include "kvm_ppc.h"
> >  #include "migration/migration.h"
> >  #include "mmu-hash64.h"
> > +#include "mmu-book3s-v3.h"
> >  #include "qom/cpu.h"
> >  
> >  #include "hw/boards.h"
> > @@ -1080,7 +1081,7 @@ static int get_htab_fd(sPAPRMachineState *spapr)
> >      return spapr->htab_fd;
> >  }
> >  
> > -static void close_htab_fd(sPAPRMachineState *spapr)
> > +void close_htab_fd(sPAPRMachineState *spapr)
> >  {
> >      if (spapr->htab_fd >= 0) {
> >          close(spapr->htab_fd);
> > @@ -1216,6 +1217,8 @@ void spapr_setup_hpt_and_vrma(sPAPRMachineState 
> > *spapr)
> >          spapr->rma_size = kvmppc_rma_size(spapr_node0_size(),
> >                                            spapr->htab_shift);
> >      }
> > +    /* We're setting up a hash table, so that means we're not radix */
> > +    spapr->patb_entry = 0;
> >  }
> >  
> >  static void find_unknown_sysbus_device(SysBusDevice *sbdev, void *opaque)
> > @@ -1246,7 +1249,11 @@ static void ppc_spapr_reset(void)
> >      /* Check for unknown sysbus devices */
> >      foreach_dynamic_sysbus_device(find_unknown_sysbus_device, NULL);
> >  
> > -    spapr->patb_entry = 0;
> > +    if (kvm_enabled()) { /* We assume Radix under KVM */
> > +        spapr->patb_entry = PATBE1_GR;
> > +    } else {
> > +        spapr->patb_entry = 0;
> > +    }
> >  
> >      /* If using KVM with radix mode available, VCPUs can be started
> >       * without a HPT because KVM will start them in radix mode. */
> > diff --git a/hw/ppc/spapr_hcall.c b/hw/ppc/spapr_hcall.c
> > index cd0d8b068c..2bf794d9cd 100644
> > --- a/hw/ppc/spapr_hcall.c
> > +++ b/hw/ppc/spapr_hcall.c
> > @@ -12,6 +12,8 @@
> >  #include "trace.h"
> >  #include "kvm_ppc.h"
> >  #include "hw/ppc/spapr_ovec.h"
> > +#include "qemu/error-report.h"
> > +#include "mmu-book3s-v3.h"
> >  
> >  struct SPRSyncState {
> >      int spr;
> > @@ -894,14 +896,120 @@ static target_ulong h_invalidate_pid(PowerPCCPU 
> > *cpu, sPAPRMachineState *spapr,
> >      return H_FUNCTION;
> >  }
> >  
> > +static void spapr_check_setup_free_hpt(sPAPRMachineState *spapr,
> > +                                       uint64_t patbe_old, uint64_t 
> > patbe_new)
> > +{
> > +    /*
> > +     * We have 4 Options:
> > +     * HASH->HASH || RADIX->RADIX || NOTHING->RADIX : Do Nothing
> > +     * HASH->RADIX                                  : Free HPT
> > +     * RADIX->HASH                                  : Allocate HPT
> > +     * NOTHING->HASH                                : Allocate HPT
> > +     * Note: NOTHING implies the case where we said the guest could choose
> > +     *       later and so assumed radix and now it's called H_REG_PROC_TBL
> > +     */
> > +
> > +    if ((patbe_old & PATBE1_GR) == (patbe_new & PATBE1_GR)) {
> > +        /* We assume RADIX, so this catches all the "Do Nothing" cases */
> > +    } else if (!(patbe_old & PATBE1_GR)) {
> > +        /* HASH->RADIX : Free HPT */
> > +        g_free(spapr->htab);
> > +        spapr->htab = NULL;
> > +        spapr->htab_shift = 0;
> > +        close_htab_fd(spapr);
> > +    } else if (!(patbe_new & PATBE1_GR)) {
> > +        /* RADIX->HASH || NOTHING->HASH : Allocate HPT */
> > +        spapr_setup_hpt_and_vrma(spapr);
> > +    }
> > +    return;
> > +}
> > +
> > +#define FLAGS_MASK              0x01FULL
> > +#define FLAGS_MAINTAIN(flags)   (!(flags & 0x10))
> > +#define FLAGS_DEREG(flags)      ((flags & 0x10) && !(flags & 0x08))
> > +#define FLAGS_NEW_RADIX(flags)  ((flags & 0x18) && (flags & 0x04))
> > +#define FLAGS_NEW_HASH(flags)   ((flags & 0x18) && !(flags & 0x04))
> > +#define FLAGS_RADIX(flags)      (flags & 0x04)
> > +#define FLAGS_HASH_SLB(flags)   (!(flags & 0x06))
> > +#define FLAGS_HASH_SEG(flags)   (!(flags & 0x04) && (flags & 0x02))
> > +#define FLAGS_GTSE(flags)       (flags & 0x01)
> 
> It's a bit more normal for simple bit tests like this to just #define
> the bitmask values and do the bitwise-& in the code, rather than
> hiding it in the macro.

OK. Will change. In order to keep the "if" statements tidy I've
reordered the clauses as well (to avoid "if (!x) else ...").

> > +
> >  static target_ulong h_register_process_table(PowerPCCPU *cpu,
> >                                               sPAPRMachineState *spapr,
> >                                               target_ulong opcode,
> >                                               target_ulong *args)
> >  {
> > -    qemu_log_mask(LOG_UNIMP, "Unimplemented SPAPR hcall 0x" TARGET_FMT_lx 
> > "%s\n",
> > -                  opcode, " (H_REGISTER_PROC_TBL)");
> > -    return H_FUNCTION;
> > +    CPUPPCState *env = &cpu->env;
> > +    target_ulong flags = args[0];
> > +    target_ulong proc_tbl = args[1];
> > +    target_ulong page_size = args[2];
> > +    target_ulong table_size = args[3];
> > +    uint64_t cproc;
> > +
> > +    if (flags & ~FLAGS_MASK) { /* Check no reserved bits are set */
> > +        return H_PARAMETER;
> > +    } else if (FLAGS_MAINTAIN(flags)) { /* Maintain current registration */
> > +        if (!!(flags & 0x4) ^ !!(spapr->patb_entry & PATBE1_GR)) {
> > +            return H_PARAMETER; /* Existing Process Table Mismatch */
> > +        }
> > +        cproc = spapr->patb_entry;
> > +    } else if (FLAGS_DEREG(flags)) { /* Deregister current process table */
> > +        /* Set to benign value: (current GR) | 0. This allows
> > +         * deregistration in KVM to succeed even if the radix bit in flags
> > +         * doesn't match the radix bit in the old PATB. */
> > +        cproc = spapr->patb_entry & PATBE1_GR;
> > +    } else if (FLAGS_NEW_RADIX(flags)) { /* Register new RADIX process 
> > table */
> > +        if (proc_tbl & 0xfff || proc_tbl >> 60) {
> > +            return H_P2;
> > +        } else if (page_size) {
> > +            return H_P3;
> > +        } else if (table_size > 24) {
> > +            return H_P4;
> > +        }
> > +        cproc = PATBE1_GR | proc_tbl | table_size;
> > +    } else { /* Register new HPT process table */
> > +        if (FLAGS_HASH_SLB(flags)) { /* SLB */
> > +            if (proc_tbl >> 38) {
> > +                return H_P2;
> > +            } else if (page_size & ~0x7) {
> > +                return H_P3;
> > +            } else if (table_size > 24) {
> > +                return H_P4;
> > +            }
> > +        } else if (FLAGS_HASH_SEG(flags)) { /* Segment Tables */
> > +            /* TODO - Not Supported */
> > +            return H_PARAMETER;
> 
> Is H_PARAMETER correct?  Usually that indicates the guest has supplied
> an invalid parameter rather than merely one the hypervisor doesn't
> support.  I'd expect H_NOT_AVAILABLE or maybe H_HARDWARE here.

The documentation says to return H_PARAMETER if any bits in "flags"
aren't supported, so I think this is correct (if a bit odd). Does that
seem OK?

> > +        }
> > +        cproc = (proc_tbl << 25) | page_size << 5 | table_size;
> > +    }
> > +
> > +    /* Check if we need to setup OR free the hpt */
> > +    spapr_check_setup_free_hpt(spapr, spapr->patb_entry, cproc);
> > +
> > +    spapr->patb_entry = cproc; /* Save new process table */
> > +    if (FLAGS_RADIX(flags) || FLAGS_HASH_SEG(flags)) { /* Use Process TBL 
> > */
> > +        env->spr[SPR_LPCR] |= LPCR_UPRT;
> > +    } else {
> > +        env->spr[SPR_LPCR] &= ~LPCR_UPRT;
> > +    }
> > +    if (FLAGS_GTSE(flags)) { /* Partition Uses Guest Translation Shootdwn 
> > */
> > +        env->spr[SPR_LPCR] |= LPCR_GTSE;
> > +    } else {
> > +        env->spr[SPR_LPCR] &= ~LPCR_GTSE;
> > +    }
> > +
> > +    if (kvm_enabled()) {
> > +        uint64_t cflags = 0;
> > +
> > +        if (FLAGS_RADIX(flags)) {
> > +            cflags |= KVM_PPC_MMUV3_RADIX;
> > +        }
> > +        if (FLAGS_GTSE(flags)) {
> > +            cflags |= KVM_PPC_MMUV3_GTSE;
> > +        }
> > +        return kvmppc_configure_v3_mmu(cpu, cflags, cproc);
> > +    }
> > +    return H_SUCCESS;
> >  }
> >  
> >  #define H_SIGNAL_SYS_RESET_ALL         -1
> > diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
> > index 08cdb83953..a964a50693 100644
> > --- a/include/hw/ppc/spapr.h
> > +++ b/include/hw/ppc/spapr.h
> > @@ -594,6 +594,7 @@ void spapr_dt_events(sPAPRMachineState *sm, void *fdt);
> >  int spapr_h_cas_compose_response(sPAPRMachineState *sm,
> >                                   target_ulong addr, target_ulong size,
> >                                   sPAPROptionVector *ov5_updates);
> > +void close_htab_fd(sPAPRMachineState *spapr);
> >  void spapr_setup_hpt_and_vrma(sPAPRMachineState *spapr);
> >  sPAPRTCETable *spapr_tce_new_table(DeviceState *owner, uint32_t liobn);
> >  void spapr_tce_table_enable(sPAPRTCETable *tcet,
> > diff --git a/target/ppc/kvm.c b/target/ppc/kvm.c
> > index adf12da1aa..a264eeacdb 100644
> > --- a/target/ppc/kvm.c
> > +++ b/target/ppc/kvm.c
> > @@ -358,6 +358,24 @@ struct ppc_radix_page_info 
> > *kvm_get_radix_page_info(void)
> >      return radix_page_info;
> >  }
> >  
> > +target_ulong kvmppc_configure_v3_mmu(PowerPCCPU *cpu, uint64_t flags,
> > +                                     uint64_t proc_tbl)
> > +{
> > +    CPUState *cs = CPU(cpu);
> > +    int ret;
> > +    struct kvm_ppc_mmuv3_cfg cfg;
> > +
> > +    cfg.flags = flags;
> > +    cfg.process_table = proc_tbl;
> 
> You can use a C99 structure initializer for this.

OK.

> > +    ret = kvm_vm_ioctl(cs->kvm_state, KVM_PPC_CONFIGURE_V3_MMU, &cfg);
> > +    switch (ret) {
> > +    case 0: return H_SUCCESS;
> > +    case -EINVAL: return H_PARAMETER;
> > +    case -ENODEV: return H_FUNCTION;
> 
> Should probably be H_NOT_AVAILABLE, AIUI PAPR only uses H_FUNCTION
> when it doesn't know about the hypercall at all.

Ah thanks, I wasn't sure of this. I'll change it to H_NOT_AVAILABLE (the
return value doesn't matter to Linux guests but I think it's good to
differentiate these cases for debugging).

> > +    default: return H_HARDWARE;
> > +    }
> > +}
> > +
> >  static long gethugepagesize(const char *mem_path)
> >  {
> >      struct statfs fs;
> > diff --git a/target/ppc/kvm_ppc.h b/target/ppc/kvm_ppc.h
> > index 0cdbe9ea0b..d1462913e3 100644
> > --- a/target/ppc/kvm_ppc.h
> > +++ b/target/ppc/kvm_ppc.h
> > @@ -33,6 +33,8 @@ int kvmppc_clear_tsr_bits(PowerPCCPU *cpu, uint32_t 
> > tsr_bits);
> >  int kvmppc_or_tsr_bits(PowerPCCPU *cpu, uint32_t tsr_bits);
> >  int kvmppc_set_tcr(PowerPCCPU *cpu);
> >  int kvmppc_booke_watchdog_enable(PowerPCCPU *cpu);
> > +target_ulong kvmppc_configure_v3_mmu(PowerPCCPU *cpu, uint64_t flags,
> > +                                     uint64_t proctbl);
> >  #ifndef CONFIG_USER_ONLY
> >  off_t kvmppc_alloc_rma(void **rma);
> >  bool kvmppc_spapr_use_multitce(void);
> 
> -- 
> David Gibson                  | I'll have my music baroque, and my code
> david AT gibson.dropbear.id.au        | minimalist, thank you.  NOT _the_ 
> _other_
>                               | _way_ _around_!
> http://www.ozlabs.org/~dgibson