Re: [PATCH v5 07/14] spapr: nested: Introduce H_GUEST_[CREATE|DELETE] hcalls.

[Nicholas Piggin]

On Fri Mar 8, 2024 at 9:19 PM AEST, Harsh Prateek Bora wrote:
> Introduce the nested PAPR hcalls:
>     - H_GUEST_CREATE which is used to create and allocate resources for
> nested guest being created.
>     - H_GUEST_DELETE which is used to delete and deallocate resources
> for the nested guest being deleted. It also supports deleting all nested
> guests at once using a deleteAll flag.
>
> Signed-off-by: Michael Neuling <mikey@neuling.org>
> Signed-off-by: Harsh Prateek Bora <harshpb@linux.ibm.com>

Reviewed-by: Nicholas Piggin <npiggin@gmail.com>

> ---
>  include/hw/ppc/spapr.h        |   4 +-
>  include/hw/ppc/spapr_nested.h |   7 +++
>  hw/ppc/spapr_nested.c         | 103 ++++++++++++++++++++++++++++++++++
>  3 files changed, 113 insertions(+), 1 deletion(-)
>
> diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
> index 2906d59137..13416fc3d7 100644
> --- a/include/hw/ppc/spapr.h
> +++ b/include/hw/ppc/spapr.h
> @@ -586,8 +586,10 @@ struct SpaprMachineState {
>  #define H_WATCHDOG              0x45C
>  #define H_GUEST_GET_CAPABILITIES 0x460
>  #define H_GUEST_SET_CAPABILITIES 0x464
> +#define H_GUEST_CREATE           0x470
> +#define H_GUEST_DELETE           0x488
>  
> -#define MAX_HCALL_OPCODE         H_GUEST_SET_CAPABILITIES
> +#define MAX_HCALL_OPCODE         H_GUEST_DELETE
>  
>  /* The hcalls above are standardized in PAPR and implemented by pHyp
>   * as well.
> diff --git a/include/hw/ppc/spapr_nested.h b/include/hw/ppc/spapr_nested.h
> index 73687e03e4..56d43e540b 100644
> --- a/include/hw/ppc/spapr_nested.h
> +++ b/include/hw/ppc/spapr_nested.h
> @@ -9,8 +9,13 @@ typedef struct SpaprMachineStateNested {
>  #define NESTED_API_KVM_HV  1
>      bool capabilities_set;
>      uint32_t pvr_base;
> +    GHashTable *guests;
>  } SpaprMachineStateNested;
>  
> +typedef struct SpaprMachineStateNestedGuest {
> +    uint32_t pvr_logical;
> +} SpaprMachineStateNestedGuest;
> +
>  /* Nested PAPR API related macros */
>  #define H_GUEST_CAPABILITIES_COPY_MEM 0x8000000000000000
>  #define H_GUEST_CAPABILITIES_P9_MODE  0x4000000000000000
> @@ -20,6 +25,8 @@ typedef struct SpaprMachineStateNested {
>  #define H_GUEST_CAP_COPY_MEM_BMAP     0
>  #define H_GUEST_CAP_P9_MODE_BMAP      1
>  #define H_GUEST_CAP_P10_MODE_BMAP     2
> +#define PAPR_NESTED_GUEST_MAX         4096
> +#define H_GUEST_DELETE_ALL_FLAG       0x8000000000000000ULL
>  
>  /*
>   * Register state for entering a nested guest with H_ENTER_NESTED.
> diff --git a/hw/ppc/spapr_nested.c b/hw/ppc/spapr_nested.c
> index 601f669060..13674c0857 100644
> --- a/hw/ppc/spapr_nested.c
> +++ b/hw/ppc/spapr_nested.c
> @@ -520,6 +520,105 @@ static target_ulong h_guest_set_capabilities(PowerPCCPU 
> *cpu,
>      }
>  }
>  
> +static void
> +destroy_guest_helper(gpointer value)
> +{
> +    struct SpaprMachineStateNestedGuest *guest = value;
> +    g_free(guest);
> +}
> +
> +static target_ulong h_guest_create(PowerPCCPU *cpu,
> +                                   SpaprMachineState *spapr,
> +                                   target_ulong opcode,
> +                                   target_ulong *args)
> +{
> +    CPUPPCState *env = &cpu->env;
> +    target_ulong flags = args[0];
> +    target_ulong continue_token = args[1];
> +    uint64_t guestid;
> +    int nguests = 0;
> +    struct SpaprMachineStateNestedGuest *guest;
> +
> +    if (flags) { /* don't handle any flags for now */
> +        return H_UNSUPPORTED_FLAG;
> +    }
> +
> +    if (continue_token != -1) {
> +        return H_P2;
> +    }
> +
> +    if (!spapr->nested.capabilities_set) {
> +        return H_STATE;
> +    }
> +
> +    if (!spapr->nested.guests) {
> +        spapr->nested.guests = g_hash_table_new_full(NULL,
> +                                                     NULL,
> +                                                     NULL,
> +                                                     destroy_guest_helper);
> +    }
> +
> +    nguests = g_hash_table_size(spapr->nested.guests);
> +
> +    if (nguests == PAPR_NESTED_GUEST_MAX) {
> +        return H_NO_MEM;
> +    }
> +
> +    /* Lookup for available guestid */
> +    for (guestid = 1; guestid < PAPR_NESTED_GUEST_MAX; guestid++) {
> +        if (!(g_hash_table_lookup(spapr->nested.guests,
> +                                  GINT_TO_POINTER(guestid)))) {
> +            break;
> +        }
> +    }
> +
> +    if (guestid == PAPR_NESTED_GUEST_MAX) {
> +        return H_NO_MEM;
> +    }
> +
> +    guest = g_try_new0(struct SpaprMachineStateNestedGuest, 1);
> +    if (!guest) {
> +        return H_NO_MEM;
> +    }
> +
> +    guest->pvr_logical = spapr->nested.pvr_base;
> +    g_hash_table_insert(spapr->nested.guests, GINT_TO_POINTER(guestid), 
> guest);
> +    env->gpr[4] = guestid;
> +
> +    return H_SUCCESS;
> +}
> +
> +static target_ulong h_guest_delete(PowerPCCPU *cpu,
> +                                   SpaprMachineState *spapr,
> +                                   target_ulong opcode,
> +                                   target_ulong *args)
> +{
> +    target_ulong flags = args[0];
> +    target_ulong guestid = args[1];
> +    struct SpaprMachineStateNestedGuest *guest;
> +
> +    /*
> +     * handle flag deleteAllGuests, if set:
> +     * guestid is ignored and all guests are deleted
> +     *
> +     */
> +    if (flags & ~H_GUEST_DELETE_ALL_FLAG) {
> +        return H_UNSUPPORTED_FLAG; /* other flag bits reserved */
> +    } else if (flags & H_GUEST_DELETE_ALL_FLAG) {
> +        g_hash_table_destroy(spapr->nested.guests);
> +        return H_SUCCESS;
> +    }
> +
> +    guest = g_hash_table_lookup(spapr->nested.guests, 
> GINT_TO_POINTER(guestid));
> +    if (!guest) {
> +        return H_P2;
> +    }
> +
> +    g_hash_table_remove(spapr->nested.guests, GINT_TO_POINTER(guestid));
> +
> +    return H_SUCCESS;
> +}
> +
>  void spapr_register_nested_hv(void)
>  {
>      spapr_register_hypercall(KVMPPC_H_SET_PARTITION_TABLE, h_set_ptbl);
> @@ -540,12 +639,16 @@ void spapr_register_nested_papr(void)
>  {
>      spapr_register_hypercall(H_GUEST_GET_CAPABILITIES, 
> h_guest_get_capabilities);
>      spapr_register_hypercall(H_GUEST_SET_CAPABILITIES, 
> h_guest_set_capabilities);
> +    spapr_register_hypercall(H_GUEST_CREATE          , h_guest_create);
> +    spapr_register_hypercall(H_GUEST_DELETE          , h_guest_delete);
>  }
>  
>  void spapr_unregister_nested_papr(void)
>  {
>      spapr_unregister_hypercall(H_GUEST_GET_CAPABILITIES);
>      spapr_unregister_hypercall(H_GUEST_SET_CAPABILITIES);
> +    spapr_unregister_hypercall(H_GUEST_CREATE);
> +    spapr_unregister_hypercall(H_GUEST_DELETE);
>  }
>  
>  #else