Re: [Qemu-devel] [QEMU-PPC] [RFC 2/3] hw/spapr/spapr_caps: Add new caps safe_[cache/bounds_check/indirect_branch]

[Suraj Jitindar Singh <sjitindarsingh@gmail.com>]

On Tue, 2018-01-09 at 10:02 -0200, joserz@linux.vnet.ibm.com wrote:
> On Tue, Jan 09, 2018 at 08:21:02PM +1100, Suraj Jitindar Singh wrote:
> > This patch adds three new capabilities:
> > cap-cfpc -> safe_cache
> > cap-sbbc -> safe_bounds_check
> > cap-ibs  -> safe_indirect_branch
> > 
> > Each capability is tristate with the possible values "broken",
> > "workaround" or "fixed". Add generic getter and setter functions
> > for
> > this new capability type. Add these new capabilities to the
> > capabilities
> > list. The maximum value for the capabilities is queried from kvm
> > through
> > new kvm capabilities. The requested values are considered to be
> > compatible if kvm can support an equal or higher value for each
> > capability.
> > 
> > Discussion:
> > Currently these new capabilities default to broken to allow for
> > backwards compatibility, is this the best option?
> > ---
> >  hw/ppc/spapr.c            |   6 ++
> >  hw/ppc/spapr_caps.c       | 224
> > ++++++++++++++++++++++++++++++++++++++++++++++
> >  include/hw/ppc/spapr.h    |  15 +++-
> >  linux-headers/linux/kvm.h |   3 +
> >  target/ppc/kvm.c          |  28 ++++++
> >  target/ppc/kvm_ppc.h      |  18 ++++
> >  6 files changed, 293 insertions(+), 1 deletion(-)
> > 
> > diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> > index 7fa45729ba..d9700b0254 100644
> > --- a/hw/ppc/spapr.c
> > +++ b/hw/ppc/spapr.c
> > @@ -1765,6 +1765,9 @@ static const VMStateDescription vmstate_spapr
> > = {
> >          &vmstate_spapr_cap_htm,
> >          &vmstate_spapr_cap_vsx,
> >          &vmstate_spapr_cap_dfp,
> > +        &vmstate_spapr_cap_cfpc,
> > +        &vmstate_spapr_cap_sbbc,
> > +        &vmstate_spapr_cap_ibs,
> >          NULL
> >      }
> >  };
> > @@ -3837,6 +3840,9 @@ static void
> > spapr_machine_class_init(ObjectClass *oc, void *data)
> >      smc->default_caps.caps[SPAPR_CAP_HTM] = SPAPR_CAP_OFF;
> >      smc->default_caps.caps[SPAPR_CAP_VSX] = SPAPR_CAP_ON;
> >      smc->default_caps.caps[SPAPR_CAP_DFP] = SPAPR_CAP_ON;
> > +    smc->default_caps.caps[SPAPR_CAP_CFPC] = SPAPR_CAP_BROKEN;
> > +    smc->default_caps.caps[SPAPR_CAP_SBBC] = SPAPR_CAP_BROKEN;
> > +    smc->default_caps.caps[SPAPR_CAP_IBS] = SPAPR_CAP_BROKEN;
> >      spapr_caps_add_properties(smc, &error_abort);
> >  }
> > 
> > diff --git a/hw/ppc/spapr_caps.c b/hw/ppc/spapr_caps.c
> > index af40f2e469..e6910aa191 100644
> > --- a/hw/ppc/spapr_caps.c
> > +++ b/hw/ppc/spapr_caps.c
> > @@ -75,6 +75,64 @@ static void spapr_cap_set_bool(Object *obj,
> > Visitor *v, const char *name,
> >                                               SPAPR_CAP_CMD_LINE;
> >  }
> > 
> > +static void spapr_cap_get_tristate(Object *obj, Visitor *v, const
> > char *name,
> > +                                   void *opaque, Error **errp)
> > +{
> > +    sPAPRCapabilityInfo *cap = opaque;
> > +    sPAPRMachineState *spapr = SPAPR_MACHINE(obj);
> > +    char *val = NULL;
> > +    uint8_t value = spapr_get_cap(spapr, cap->index);
> > +
> > +    switch (value) {
> > +    case SPAPR_CAP_BROKEN:
> > +        val = g_strdup("broken");
> > +        break;
> > +    case SPAPR_CAP_WORKAROUND:
> > +        val = g_strdup("workaround");
> > +        break;
> > +    case SPAPR_CAP_FIXED:
> > +        val = g_strdup("fixed");
> > +        break;
> > +    default:
> > +        break;
> 
> Hello Suraj
> 
> Is default a possible case? If so, will val be handled correctly by
> visit_type_str and g_free?

The default case would represent an internal error somehow and should
throw an error. Will change that.

Thanks :)

> 
> if not, maybe a throwing an error like you did in
> spapr_cap_set_tristate could be better.
> 
> > +    }
> > +
> > +    visit_type_str(v, name, &val, errp);
> > +    g_free(val);
> > +}
> > +
> > +static void spapr_cap_set_tristate(Object *obj, Visitor *v, const
> > char *name,
> > +                                   void *opaque, Error **errp)
> > +{
> > +    sPAPRCapabilityInfo *cap = opaque;
> > +    sPAPRMachineState *spapr = SPAPR_MACHINE(obj);
> > +    char *val;
> > +    Error *local_err = NULL;
> > +    uint8_t value;
> > +
> > +    visit_type_str(v, name, &val, &local_err);
> > +    if (local_err) {
> > +        error_propagate(errp, local_err);
> > +        return;
> > +    }
> > +
> > +    if (!strcasecmp(val, "broken")) {
> > +        value = SPAPR_CAP_BROKEN;
> > +    } else if (!strcasecmp(val, "workaround")) {
> > +        value = SPAPR_CAP_WORKAROUND;
> > +    } else if (!strcasecmp(val, "fixed")) {
> > +        value = SPAPR_CAP_FIXED;
> > +    } else {
> > +        error_setg(errp, "Invalid capability mode \"%s\" for cap-
> > %s", val,
> > +                   cap->name);
> > +        goto out;
> > +    }
> > +
> > +    spapr->cmd_line_caps.caps[cap->index] = value |
> > SPAPR_CAP_CMD_LINE;
> > +out:
> > +    g_free(val);
> > +}
> > +
> >  static void cap_htm_allow(sPAPRMachineState *spapr, uint8_t val,
> > Error **errp)
> >  {
> >      if (!val) {
> > @@ -122,6 +180,31 @@ static void cap_dfp_allow(sPAPRMachineState
> > *spapr, uint8_t val, Error **errp)
> >      }
> >  }
> > 
> > +static void cap_safe_cache_allow(sPAPRMachineState *spapr, uint8_t
> > val,
> > +                                 Error **errp)
> > +{
> > +    if (kvm_enabled() && (val > kvmppc_get_cap_safe_cache())) {
> > +        error_setg(errp, "Requested safe cache capability level
> > not supported by kvm, try a different value for cap-cfpc");
> > +    }
> > +}
> > +
> > +static void cap_safe_bounds_check_allow(sPAPRMachineState *spapr,
> > uint8_t val,
> > +                                        Error **errp)
> > +{
> > +    if (kvm_enabled() && (val >
> > kvmppc_get_cap_safe_bounds_check())) {
> > +        error_setg(errp, "Requested safe bounds check capability
> > level not supported by kvm, try a different value for cap-sbbc");
> > +    }
> > +}
> > +
> > +static void cap_safe_indirect_branch_allow(sPAPRMachineState
> > *spapr,
> > +                                           uint8_t val, Error
> > **errp)
> > +{
> > +    if (kvm_enabled() && (val >
> > kvmppc_get_cap_safe_indirect_branch())) {
> > +        error_setg(errp, "Requested safe indirect branch
> > capability level not supported by kvm, try a different value for
> > cap-ibs");
> > +    }
> > +}
> > +
> > +#define VALUE_DESC_TRISTATE     " (broken, workaround, fixed)"
> > 
> >  sPAPRCapabilityInfo capability_table[SPAPR_CAP_NUM] = {
> >      [SPAPR_CAP_HTM] = {
> > @@ -154,6 +237,36 @@ sPAPRCapabilityInfo
> > capability_table[SPAPR_CAP_NUM] = {
> >          .type = "bool",
> >          .allow = cap_dfp_allow,
> >      },
> > +    [SPAPR_CAP_CFPC] = {
> > +        .name = "cfpc",
> > +        .description = "Cache Flush on Privilege Change",
> > +        .options = VALUE_DESC_TRISTATE,
> > +        .index = SPAPR_CAP_CFPC,
> > +        .get = spapr_cap_get_tristate,
> > +        .set = spapr_cap_set_tristate,
> > +        .type = "string",
> > +        .allow = cap_safe_cache_allow,
> > +    },
> > +    [SPAPR_CAP_SBBC] = {
> > +        .name = "sbbc",
> > +        .description = "Speculation Barrier Bounds Checking",
> > +        .options = VALUE_DESC_TRISTATE,
> > +        .index = SPAPR_CAP_SBBC,
> > +        .get = spapr_cap_get_tristate,
> > +        .set = spapr_cap_set_tristate,
> > +        .type = "string",
> > +        .allow = cap_safe_bounds_check_allow,
> > +    },
> > +    [SPAPR_CAP_IBS] = {
> > +        .name = "ibs",
> > +        .description = "Indirect Branch Serialisation",
> > +        .options = VALUE_DESC_TRISTATE,
> > +        .index = SPAPR_CAP_IBS,
> > +        .get = spapr_cap_get_tristate,
> > +        .set = spapr_cap_set_tristate,
> > +        .type = "string",
> > +        .allow = cap_safe_indirect_branch_allow,
> > +    },
> >  };
> > 
> >  static sPAPRCapabilities default_caps_with_cpu(sPAPRMachineState
> > *spapr,
> > @@ -326,6 +439,117 @@ const VMStateDescription
> > vmstate_spapr_cap_dfp = {
> >      },
> >  };
> > 
> > +static bool spapr_cap_safe_cache_needed(void *opaque)
> > +{
> > +    sPAPRMachineState *spapr = opaque;
> > +
> > +    return !!(spapr->cmd_line_caps.caps[SPAPR_CAP_CFPC] &
> > SPAPR_CAP_CMD_LINE);
> > +}
> > +
> > +static int spapr_cap_safe_cache_pre_save(void *opaque)
> > +{
> > +    sPAPRMachineState *spapr = opaque;
> > +
> > +    spapr->mig_caps.caps[SPAPR_CAP_CFPC] =
> > +        spapr->cmd_line_caps.caps[SPAPR_CAP_CFPC];
> > +    return 0;
> > +}
> > +
> > +static int spapr_cap_safe_cache_pre_load(void *opaque)
> > +{
> > +    sPAPRMachineState *spapr = opaque;
> > +
> > +    spapr->mig_caps.caps[SPAPR_CAP_CFPC] = 0;
> > +    return 0;
> > +}
> > +
> > +const VMStateDescription vmstate_spapr_cap_cfpc = {
> > +    .name = "spapr/cap_cfpc",
> > +    .version_id = 1,
> > +    .minimum_version_id = 1,
> > +    .needed = spapr_cap_safe_cache_needed,
> > +    .pre_save = spapr_cap_safe_cache_pre_save,
> > +    .pre_load = spapr_cap_safe_cache_pre_load,
> > +    .fields = (VMStateField[]) {
> > +        VMSTATE_UINT8(mig_caps.caps[SPAPR_CAP_CFPC],
> > sPAPRMachineState),
> > +        VMSTATE_END_OF_LIST()
> > +    },
> > +};
> > +
> > +static bool spapr_cap_safe_bounds_check_needed(void *opaque)
> > +{
> > +    sPAPRMachineState *spapr = opaque;
> > +
> > +    return !!(spapr->cmd_line_caps.caps[SPAPR_CAP_SBBC] &
> > SPAPR_CAP_CMD_LINE);
> > +}
> > +
> > +static int spapr_cap_safe_bounds_check_pre_save(void *opaque)
> > +{
> > +    sPAPRMachineState *spapr = opaque;
> > +
> > +    spapr->mig_caps.caps[SPAPR_CAP_SBBC] =
> > +        spapr->cmd_line_caps.caps[SPAPR_CAP_SBBC];
> > +    return 0;
> > +}
> > +
> > +static int spapr_cap_safe_bounds_check_pre_load(void *opaque)
> > +{
> > +    sPAPRMachineState *spapr = opaque;
> > +
> > +    spapr->mig_caps.caps[SPAPR_CAP_SBBC] = 0;
> > +    return 0;
> > +}
> > +
> > +const VMStateDescription vmstate_spapr_cap_sbbc = {
> > +    .name = "spapr/cap_sbbc",
> > +    .version_id = 1,
> > +    .minimum_version_id = 1,
> > +    .needed = spapr_cap_safe_bounds_check_needed,
> > +    .pre_save = spapr_cap_safe_bounds_check_pre_save,
> > +    .pre_load = spapr_cap_safe_bounds_check_pre_load,
> > +    .fields = (VMStateField[]) {
> > +        VMSTATE_UINT8(mig_caps.caps[SPAPR_CAP_SBBC],
> > sPAPRMachineState),
> > +        VMSTATE_END_OF_LIST()
> > +    },
> > +};
> > +
> > +static bool spapr_cap_safe_indirect_branch_needed(void *opaque)
> > +{
> > +    sPAPRMachineState *spapr = opaque;
> > +
> > +    return !!(spapr->cmd_line_caps.caps[SPAPR_CAP_IBS] &
> > SPAPR_CAP_CMD_LINE);
> > +}
> > +
> > +static int spapr_cap_safe_indirect_branch_pre_save(void *opaque)
> > +{
> > +    sPAPRMachineState *spapr = opaque;
> > +
> > +    spapr->mig_caps.caps[SPAPR_CAP_IBS] =
> > +        spapr->cmd_line_caps.caps[SPAPR_CAP_IBS];
> > +    return 0;
> > +}
> > +
> > +static int spapr_cap_safe_indirect_branch_pre_load(void *opaque)
> > +{
> > +    sPAPRMachineState *spapr = opaque;
> > +
> > +    spapr->mig_caps.caps[SPAPR_CAP_IBS] = 0;
> > +    return 0;
> > +}
> > +
> > +const VMStateDescription vmstate_spapr_cap_ibs = {
> > +    .name = "spapr/cap_ibs",
> > +    .version_id = 1,
> > +    .minimum_version_id = 1,
> > +    .needed = spapr_cap_safe_indirect_branch_needed,
> > +    .pre_save = spapr_cap_safe_indirect_branch_pre_save,
> > +    .pre_load = spapr_cap_safe_indirect_branch_pre_load,
> > +    .fields = (VMStateField[]) {
> > +        VMSTATE_UINT8(mig_caps.caps[SPAPR_CAP_IBS],
> > sPAPRMachineState),
> > +        VMSTATE_END_OF_LIST()
> > +    },
> > +};
> > +
> >  void spapr_caps_reset(sPAPRMachineState *spapr)
> >  {
> >      sPAPRCapabilities caps;
> > diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
> > index 2804fbbf12..2db2f3e2e2 100644
> > --- a/include/hw/ppc/spapr.h
> > +++ b/include/hw/ppc/spapr.h
> > @@ -62,8 +62,14 @@ typedef enum {
> >  #define SPAPR_CAP_VSX                   0x01
> >  /* Decimal Floating Point */
> >  #define SPAPR_CAP_DFP                   0x02
> > +/* Cache Flush on Privilege Change */
> > +#define SPAPR_CAP_CFPC                  0x03
> > +/* Speculation Barrier Bounds Checking */
> > +#define SPAPR_CAP_SBBC                  0x04
> > +/* Indirect Branch Serialisation */
> > +#define SPAPR_CAP_IBS                   0x05
> >  /* Num Caps */
> > -#define SPAPR_CAP_NUM                   (SPAPR_CAP_DFP + 1)
> > +#define SPAPR_CAP_NUM                   (SPAPR_CAP_IBS + 1)
> > 
> >  /*
> >   * Capability Values
> > @@ -73,6 +79,10 @@ typedef enum {
> >  /* Bool Caps */
> >  #define SPAPR_CAP_OFF                   0x00
> >  #define SPAPR_CAP_ON                    0x01
> > +/* Broken | Workaround | Fixed Caps */
> > +#define SPAPR_CAP_BROKEN                0x00
> > +#define SPAPR_CAP_WORKAROUND            0x01
> > +#define SPAPR_CAP_FIXED                 0x02
> > 
> >  typedef struct sPAPRCapabilities sPAPRCapabilities;
> >  struct sPAPRCapabilities {
> > @@ -763,6 +773,9 @@ qemu_irq spapr_qirq(sPAPRMachineState *spapr,
> > int irq);
> >  extern const VMStateDescription vmstate_spapr_cap_htm;
> >  extern const VMStateDescription vmstate_spapr_cap_vsx;
> >  extern const VMStateDescription vmstate_spapr_cap_dfp;
> > +extern const VMStateDescription vmstate_spapr_cap_cfpc;
> > +extern const VMStateDescription vmstate_spapr_cap_sbbc;
> > +extern const VMStateDescription vmstate_spapr_cap_ibs;
> > 
> >  static inline uint8_t spapr_get_cap(sPAPRMachineState *spapr, int
> > cap)
> >  {
> > diff --git a/linux-headers/linux/kvm.h b/linux-headers/linux/kvm.h
> > index ce6c2f11f4..0abe0a0abb 100644
> > --- a/linux-headers/linux/kvm.h
> > +++ b/linux-headers/linux/kvm.h
> > @@ -932,6 +932,9 @@ struct kvm_ppc_resize_hpt {
> >  #define KVM_CAP_HYPERV_SYNIC2 148
> >  #define KVM_CAP_HYPERV_VP_INDEX 149
> >  #define KVM_CAP_S390_AIS_MIGRATION 150
> > +#define KVM_CAP_PPC_SAFE_CACHE 151
> > +#define KVM_CAP_PPC_SAFE_BOUNDS_CHECK 152
> > +#define KVM_CAP_PPC_SAFE_INDIRECT_BRANCH 153
> > 
> >  #ifdef KVM_CAP_IRQ_ROUTING
> > 
> > diff --git a/target/ppc/kvm.c b/target/ppc/kvm.c
> > index 518dd06e98..818499237c 100644
> > --- a/target/ppc/kvm.c
> > +++ b/target/ppc/kvm.c
> > @@ -89,6 +89,9 @@ static int cap_mmu_radix;
> >  static int cap_mmu_hash_v3;
> >  static int cap_resize_hpt;
> >  static int cap_ppc_pvr_compat;
> > +static int cap_ppc_safe_cache;
> > +static int cap_ppc_safe_bounds_check;
> > +static int cap_ppc_safe_indirect_branch;
> > 
> >  static uint32_t debug_inst_opcode;
> > 
> > @@ -147,6 +150,16 @@ int kvm_arch_init(MachineState *ms, KVMState
> > *s)
> >      cap_mmu_radix = kvm_vm_check_extension(s,
> > KVM_CAP_PPC_MMU_RADIX);
> >      cap_mmu_hash_v3 = kvm_vm_check_extension(s,
> > KVM_CAP_PPC_MMU_HASH_V3);
> >      cap_resize_hpt = kvm_vm_check_extension(s,
> > KVM_CAP_SPAPR_RESIZE_HPT);
> > +    cap_ppc_safe_cache = kvm_vm_check_extension(s,
> > KVM_CAP_PPC_SAFE_CACHE);
> > +    cap_ppc_safe_cache = cap_ppc_safe_cache > 0 ?
> > cap_ppc_safe_cache : 0;
> > +    cap_ppc_safe_bounds_check = kvm_vm_check_extension(s,
> > +                                KVM_CAP_PPC_SAFE_BOUNDS_CHECK);
> > +    cap_ppc_safe_bounds_check = cap_ppc_safe_bounds_check > 0 ?
> > +                                cap_ppc_safe_bounds_check : 0;
> > +    cap_ppc_safe_indirect_branch = kvm_vm_check_extension(s,
> > +                                   KVM_CAP_PPC_SAFE_INDIRECT_BRANC
> > H);
> > +    cap_ppc_safe_indirect_branch = cap_ppc_safe_indirect_branch >
> > 0 ?
> > +                                   cap_ppc_safe_indirect_branch :
> > 0;
> >      /*
> >       * Note: setting it to false because there is not such
> > capability
> >       * in KVM at this moment.
> > @@ -2456,6 +2469,21 @@ bool kvmppc_has_cap_mmu_hash_v3(void)
> >      return cap_mmu_hash_v3;
> >  }
> > 
> > +int kvmppc_get_cap_safe_cache(void)
> > +{
> > +    return cap_ppc_safe_cache;
> > +}
> > +
> > +int kvmppc_get_cap_safe_bounds_check(void)
> > +{
> > +    return cap_ppc_safe_bounds_check;
> > +}
> > +
> > +int kvmppc_get_cap_safe_indirect_branch(void)
> > +{
> > +    return cap_ppc_safe_indirect_branch;
> > +}
> > +
> >  PowerPCCPUClass *kvm_ppc_get_host_cpu_class(void)
> >  {
> >      uint32_t host_pvr = mfpvr();
> > diff --git a/target/ppc/kvm_ppc.h b/target/ppc/kvm_ppc.h
> > index ecb55493cc..39830baa77 100644
> > --- a/target/ppc/kvm_ppc.h
> > +++ b/target/ppc/kvm_ppc.h
> > @@ -59,6 +59,9 @@ bool kvmppc_has_cap_fixup_hcalls(void);
> >  bool kvmppc_has_cap_htm(void);
> >  bool kvmppc_has_cap_mmu_radix(void);
> >  bool kvmppc_has_cap_mmu_hash_v3(void);
> > +int kvmppc_get_cap_safe_cache(void);
> > +int kvmppc_get_cap_safe_bounds_check(void);
> > +int kvmppc_get_cap_safe_indirect_branch(void);
> >  int kvmppc_enable_hwrng(void);
> >  int kvmppc_put_books_sregs(PowerPCCPU *cpu);
> >  PowerPCCPUClass *kvm_ppc_get_host_cpu_class(void);
> > @@ -290,6 +293,21 @@ static inline bool
> > kvmppc_has_cap_mmu_hash_v3(void)
> >      return false;
> >  }
> > 
> > +static inline int kvmppc_get_cap_safe_cache(void)
> > +{
> > +    return 0;
> > +}
> > +
> > +static inline int kvmppc_get_cap_safe_bounds_check(void)
> > +{
> > +    return 0;
> > +}
> > +
> > +static inline int kvmppc_get_cap_safe_indirect_branch(void)
> > +{
> > +    return 0;
> > +}
> > +
> >  static inline int kvmppc_enable_hwrng(void)
> >  {
> >      return -1;
> > -- 
> > 2.13.6
> > 
> > 
> 
>