Re: [PATCH v4 4/8] hw/intc: GICv3 ITS Command processing

[Peter Maydell <peter.maydell@linaro.org>]

On Wed, 2 Jun 2021 at 19:00, Shashi Mallela <shashi.mallela@linaro.org> wrote:
>
> Added ITS command queue handling for MAPTI,MAPI commands,handled ITS
> translation which triggers an LPI via INT command as well as write
> to GITS_TRANSLATER register,defined enum to differentiate between ITS
> command interrupt trigger and GITS_TRANSLATER based interrupt trigger.
> Each of these commands make use of other functionalities implemented to
> get device table entry,collection table entry or interrupt translation
> table entry required for their processing.
>
> Signed-off-by: Shashi Mallela <shashi.mallela@linaro.org>
> ---
>  hw/intc/arm_gicv3_its.c            | 334 +++++++++++++++++++++++++++++
>  hw/intc/gicv3_internal.h           |  12 ++
>  include/hw/intc/arm_gicv3_common.h |   2 +
>  3 files changed, 348 insertions(+)
>
> diff --git a/hw/intc/arm_gicv3_its.c b/hw/intc/arm_gicv3_its.c
> index 6551c577b3..82bb5b84ef 100644
> --- a/hw/intc/arm_gicv3_its.c
> +++ b/hw/intc/arm_gicv3_its.c
> @@ -28,6 +28,13 @@ struct GICv3ITSClass {
>      void (*parent_reset)(DeviceState *dev);
>  };
>
> +typedef enum ItsCmdType {
> +    NONE = 0, /* internal indication for GITS_TRANSLATER write */
> +    CLEAR = 1,
> +    DISCARD = 2,
> +    INT = 3,
> +} ItsCmdType;
> +
>  static uint64_t baser_base_addr(uint64_t value, uint32_t page_sz)
>  {
>      uint64_t result = 0;
> @@ -49,6 +56,315 @@ static uint64_t baser_base_addr(uint64_t value, uint32_t page_sz)
>      return result;
>  }
>
> +static bool get_cte(GICv3ITSState *s, uint16_t icid, uint64_t *cte,
> +                    MemTxResult *res)
> +{
> +    AddressSpace *as = &s->gicv3->dma_as;
> +    uint64_t l2t_addr;
> +    uint64_t value;
> +    bool valid_l2t;
> +    uint32_t l2t_id;
> +    uint32_t max_l2_entries;
> +    bool status = false;
> +
> +    if (s->ct.indirect) {
> +        l2t_id = icid / (s->ct.page_sz / L1TABLE_ENTRY_SIZE);
> +
> +        value = address_space_ldq_le(as,
> +                                     s->ct.base_addr +
> +                                     (l2t_id * L1TABLE_ENTRY_SIZE),
> +                                     MEMTXATTRS_UNSPECIFIED, res);
> +
> +        if (*res == MEMTX_OK) {
> +            valid_l2t = (value >> VALID_SHIFT) & VALID_MASK;

VALID_MASK should be the mask in its shifted location
(for consistency with how the FIELD macros do it). Then
this is just
   valid_l2t = (value & VALID_MASK) != 0;

> +
> +            if (valid_l2t) {
> +                max_l2_entries = s->ct.page_sz / s->ct.entry_sz;
> +
> +                l2t_addr = value & ((1ULL << 51) - 1);
> +
> +                *cte =  address_space_ldq_le(as, l2t_addr +
> +                                    ((icid % max_l2_entries) * GITS_CTE_SIZE),
> +                                    MEMTXATTRS_UNSPECIFIED, res);
> +           }
> +       }
> +    } else {
> +        /* Flat level table */
> +        *cte =  address_space_ldq_le(as, s->ct.base_addr +
> +                                     (icid * GITS_CTE_SIZE),
> +                                      MEMTXATTRS_UNSPECIFIED, res);
> +    }
> +
> +    if (*cte & VALID_MASK) {
> +        status = true;
> +    }
> +
> +    return status;

You don't need the 'status' variable, you can just
     return (*cte & VALID_MASK) != 0;

(Looks like this code is already assuming VALID_MASK is the mask
in its shifted location, and so inconsistent with your current definition ?)

> +static bool get_ite(GICv3ITSState *s, uint32_t eventid, uint64_t dte,
> +                    uint16_t *icid, uint32_t *pIntid, MemTxResult *res)
> +{
> +    AddressSpace *as = &s->gicv3->dma_as;
> +    uint64_t itt_addr;
> +    bool status = false;
> +    uint64_t itel = 0;
> +    uint32_t iteh = 0;
> +
> +    itt_addr = (dte >> 6ULL) & ITTADDR_MASK;
> +    itt_addr <<= ITTADDR_SHIFT; /* 256 byte aligned */
> +
> +    itel = address_space_ldq_le(as, itt_addr + (eventid * sizeof(uint64_t)),
> +                                MEMTXATTRS_UNSPECIFIED, res);
> +
> +    if (*res == MEMTX_OK) {
> +        iteh = address_space_ldl_le(as, itt_addr + ((eventid +
> +                                    sizeof(uint64_t)) * sizeof(uint32_t)),
> +                                    MEMTXATTRS_UNSPECIFIED, res);
> +
> +        if (*res == MEMTX_OK) {
> +            if (itel & VALID_MASK) {
> +                if ((itel >> ITE_ENTRY_INTTYPE_SHIFT) & GITS_TYPE_PHYSICAL) {
> +                    *pIntid = (itel >> ITE_ENTRY_INTID_SHIFT) &
> +                               ITE_ENTRY_INTID_MASK;

More _MASK constants that don't have the same semantics as the
registerfields versions. Please can you change all of these ?

> +                    *icid = iteh & ITE_ENTRY_ICID_MASK;
> +                    status = true;
> +                }
> +            }
> +        }
> +    }
> +    return status;
> +}
> +
> +    if ((devid > s->dt.max_devids) || !dte_valid || !ite_valid ||
> +            !cte_valid || (eventid > max_eventid)) {
> +        qemu_log_mask(LOG_GUEST_ERROR,
> +                      "%s: invalid interrupt translation table attributes "
> +                      "devid %d or eventid %d\n",
> +                      __func__, devid, eventid);
> +        /*
> +         * in this implementation,in case of error

Another missing space after comma.

> +        /*
> +         * in this implementation,in case of error

And again.

> +         * we ignore this command and move onto the next
> +         * command in the queue
> +         */

thanks
-- PMM