Re: [PATCH v4 6/8] hw/intc: GICv3 redistributor ITS processing

[Eric Auger <eauger@redhat.com>]

Hi Shashi,

On 6/2/21 8:00 PM, Shashi Mallela wrote:
> Implemented lpi processing at redistributor to get lpi config info
s/Implemented/Implement here are elsewhere.
> from lpi configuration table,determine priority,set pending state in
> lpi pending table and forward the lpi to cpuif.Added logic to invoke
> redistributor lpi processing with translated LPI which set/clear LPI
> from ITS device as part of ITS INT,CLEAR,DISCARD command and
> GITS_TRANSLATER processing.
> 
> Signed-off-by: Shashi Mallela <shashi.mallela@linaro.org>
> ---
>  hw/intc/arm_gicv3.c                |   9 ++
>  hw/intc/arm_gicv3_common.c         |   1 +
>  hw/intc/arm_gicv3_cpuif.c          |   7 +-
>  hw/intc/arm_gicv3_its.c            |  14 ++-
>  hw/intc/arm_gicv3_redist.c         | 145 +++++++++++++++++++++++++++++
>  hw/intc/gicv3_internal.h           |  10 ++
>  include/hw/intc/arm_gicv3_common.h |  10 ++
>  7 files changed, 190 insertions(+), 6 deletions(-)
> 
> diff --git a/hw/intc/arm_gicv3.c b/hw/intc/arm_gicv3.c
> index d63f8af604..4d19190b9c 100644
> --- a/hw/intc/arm_gicv3.c
> +++ b/hw/intc/arm_gicv3.c
> @@ -165,6 +165,15 @@ static void gicv3_redist_update_noirqset(GICv3CPUState *cs)
>          cs->hppi.grp = gicv3_irq_group(cs->gic, cs, cs->hppi.irq);
>      }
>  
> +    if (cs->gic->lpi_enable && cs->lpivalid) {
> +        if (irqbetter(cs, cs->hpplpi.irq, cs->hpplpi.prio)) {
> +            cs->hppi.irq = cs->hpplpi.irq;
> +            cs->hppi.prio = cs->hpplpi.prio;
> +            cs->hppi.grp = cs->hpplpi.grp;
> +            seenbetter = true;
> +        }
> +    }
> +
>      /* If the best interrupt we just found would preempt whatever
>       * was the previous best interrupt before this update, then
>       * we know it's definitely the best one now.
> diff --git a/hw/intc/arm_gicv3_common.c b/hw/intc/arm_gicv3_common.c
> index 53dea2a775..223db16fec 100644
> --- a/hw/intc/arm_gicv3_common.c
> +++ b/hw/intc/arm_gicv3_common.c
> @@ -435,6 +435,7 @@ static void arm_gicv3_common_reset(DeviceState *dev)
>          memset(cs->gicr_ipriorityr, 0, sizeof(cs->gicr_ipriorityr));
>  
>          cs->hppi.prio = 0xff;
> +        cs->hpplpi.prio = 0xff;
>  
>          /* State in the CPU interface must *not* be reset here, because it
>           * is part of the CPU's reset domain, not the GIC device's.
> diff --git a/hw/intc/arm_gicv3_cpuif.c b/hw/intc/arm_gicv3_cpuif.c
> index 81f94c7f4a..5be3efaa3f 100644
> --- a/hw/intc/arm_gicv3_cpuif.c
> +++ b/hw/intc/arm_gicv3_cpuif.c
> @@ -898,10 +898,12 @@ static void icc_activate_irq(GICv3CPUState *cs, int irq)
>          cs->gicr_iactiver0 = deposit32(cs->gicr_iactiver0, irq, 1, 1);
>          cs->gicr_ipendr0 = deposit32(cs->gicr_ipendr0, irq, 1, 0);
>          gicv3_redist_update(cs);
> -    } else {
> +    } else if (irq < GICV3_LPI_INTID_START) {
>          gicv3_gicd_active_set(cs->gic, irq);
>          gicv3_gicd_pending_clear(cs->gic, irq);
>          gicv3_update(cs->gic, irq, 1);
> +    } else {
> +        gicv3_redist_lpi_pending(cs, irq, 0);
>      }
>  }
>  
> @@ -1317,7 +1319,8 @@ static void icc_eoir_write(CPUARMState *env, const ARMCPRegInfo *ri,
>      trace_gicv3_icc_eoir_write(is_eoir0 ? 0 : 1,
>                                 gicv3_redist_affid(cs), value);
>  
> -    if (irq >= cs->gic->num_irq) {
> +    if ((irq >= cs->gic->num_irq) &&  (!(cs->gic->lpi_enable &&
> +        (irq >= GICV3_LPI_INTID_START)))) {
>          /* This handles two cases:
>           * 1. If software writes the ID of a spurious interrupt [ie 1020-1023]
>           * to the GICC_EOIR, the GIC ignores that write.
> diff --git a/hw/intc/arm_gicv3_its.c b/hw/intc/arm_gicv3_its.c
> index 0a978cf55b..e0fbd4041f 100644
> --- a/hw/intc/arm_gicv3_its.c
> +++ b/hw/intc/arm_gicv3_its.c
> @@ -211,6 +211,7 @@ static MemTxResult process_int(GICv3ITSState *s, uint64_t value,
>      bool ite_valid = false;
>      uint64_t cte = 0;
>      bool cte_valid = false;
> +    uint64_t rdbase;
>      uint64_t itel = 0;
>      uint32_t iteh = 0;
>  
> @@ -267,10 +268,15 @@ static MemTxResult process_int(GICv3ITSState *s, uint64_t value,
>           * command in the queue
>           */
>      } else {
> -        /*
> -         * Current implementation only supports rdbase == procnum
> -         * Hence rdbase physical address is ignored
> -         */
> +        rdbase = (cte >> 1U) & RDBASE_PROCNUM_MASK;
> +        assert(rdbase <= s->gicv3->num_cpu);
> +
> +        if ((cmd == CLEAR) || (cmd == DISCARD)) {
> +            gicv3_redist_process_lpi(&s->gicv3->cpu[rdbase], pIntid, 0);
> +        } else {
> +            gicv3_redist_process_lpi(&s->gicv3->cpu[rdbase], pIntid, 1);
> +        }
> +
>          if (cmd == DISCARD) {
>              /* remove mapping from interrupt translation table */
>              res = update_ite(s, eventid, dte, itel, iteh);
> diff --git a/hw/intc/arm_gicv3_redist.c b/hw/intc/arm_gicv3_redist.c
> index fb9a4ee3cc..bfc6e4e9b9 100644
> --- a/hw/intc/arm_gicv3_redist.c
> +++ b/hw/intc/arm_gicv3_redist.c
> @@ -255,6 +255,11 @@ static MemTxResult gicr_writel(GICv3CPUState *cs, hwaddr offset,
>          if (cs->gicr_typer & GICR_TYPER_PLPIS) {
>              if (value & GICR_CTLR_ENABLE_LPIS) {
>                  cs->gicr_ctlr |= GICR_CTLR_ENABLE_LPIS;
> +                /* Check for any pending interr in pending table */
> +                cs->lpivalid = false;
> +                cs->hpplpi.prio = 0xff;
> +                gicv3_redist_update_lpi(cs);
> +                gicv3_redist_update(cs);
>              } else {
>                  cs->gicr_ctlr &= ~GICR_CTLR_ENABLE_LPIS;
>              }
> @@ -534,6 +539,146 @@ MemTxResult gicv3_redist_write(void *opaque, hwaddr offset, uint64_t data,
>      return r;
>  }
>  
> +void gicv3_redist_update_lpi(GICv3CPUState *cs)
> +{
> +    /*
> +     * This function scans the LPI pending table and for each pending
> +     * LPI, reads the corresponding entry from LPI configuration table
> +     * to extract the priority info and determine if the LPI priority
> +     * is lower than the current high priority interrupt.If yes, update> +     * high priority pending interrupt to that of LPI.

"update high priority pending interrupt to that of LPI" may need some
rewording
> +     */
> +    AddressSpace *as = &cs->gic->dma_as;
> +    uint64_t lpict_baddr, lpipt_baddr;
> +    uint32_t pendt_size = 0;
> +    uint8_t lpite;
> +    uint8_t prio, pend;
> +    int i;
> +    uint64_t idbits;
> +
> +    idbits = MIN(FIELD_EX64(cs->gicr_propbaser, GICR_PROPBASER, IDBITS),
> +                 GICD_TYPER_IDBITS);
> +
> +    if ((!cs->gicr_ctlr & GICR_CTLR_ENABLE_LPIS) || !cs->gicr_propbaser ||
> +        !cs->gicr_pendbaser || (idbits < GICR_PROPBASER_IDBITS_THRESHOLD)) {
> +        return;
> +    }
> +
> +    lpict_baddr = cs->gicr_propbaser & R_GICR_PROPBASER_PHYADDR_MASK;
> +
> +    lpipt_baddr = cs->gicr_pendbaser & R_GICR_PENDBASER_PHYADDR_MASK;
> +
> +    /* Determine the highest priority pending interrupt among LPIs */
> +    pendt_size = (1ULL << (idbits + 1));
> +
> +    for (i = 0; i < pendt_size / 8; i++) {
> +        address_space_read(as, lpipt_baddr +
> +                (((GICV3_LPI_INTID_START + i) / 8) * sizeof(pend)),
> +                MEMTXATTRS_UNSPECIFIED, &pend, sizeof(pend));
> +
> +        if ((1 << ((GICV3_LPI_INTID_START + i) % 8)) & pend) {
> +            address_space_read(as, lpict_baddr + (i * sizeof(lpite)),
> +                      MEMTXATTRS_UNSPECIFIED, &lpite, sizeof(lpite));
> +
> +            if (!(lpite & LPI_CTE_ENABLED)) {
> +                continue;
> +            }
> +
> +            if (cs->gic->gicd_ctlr & GICD_CTLR_DS) {
> +                prio = lpite & LPI_PRIORITY_MASK;
> +            } else {
> +                prio = lpite & LPI_SPRIORITY_MASK;
> +            }
> +
> +            if (prio <= cs->hpplpi.prio) {
> +                cs->hpplpi.irq = GICV3_LPI_INTID_START + i;
> +                cs->hpplpi.prio = prio;
> +                /* LPIs are always non-secure Grp1 interrupts */
> +                cs->hpplpi.grp = GICV3_G1NS;
> +                cs->lpivalid = true;
> +            }
> +        }
> +    }
> +}
> +
nit: add a comment to explain what the function does, that's not
straightforward gievn its name.
> +void gicv3_redist_lpi_pending(GICv3CPUState *cs, int irq, int level)
> +{
> +    AddressSpace *as = &cs->gic->dma_as;
> +    uint64_t lpipt_baddr;
> +    bool ispend = false;
> +    uint8_t pend;
> +
> +    /*
> +     * get the bit value corresponding to this irq in the
> +     * lpi pending table
> +     */
> +    lpipt_baddr = cs->gicr_pendbaser & R_GICR_PENDBASER_PHYADDR_MASK;
> +
> +    address_space_read(as, lpipt_baddr + ((irq / 8) * sizeof(pend)),
> +                         MEMTXATTRS_UNSPECIFIED, &pend, sizeof(pend));
> +    ispend = ((pend >> (irq % 8)) & 0x1);
> +
> +    if (ispend) {
> +        if (!level) {
> +            /*
> +             * clear the pending bit and update the lpi pending table
> +             */
> +            pend &= ~(1 << (irq % 8));
> +
> +            address_space_write(as, lpipt_baddr + ((irq / 8) * sizeof(pend)),
> +                                 MEMTXATTRS_UNSPECIFIED, &pend, sizeof(pend));
> +        }
> +    } else {
> +        if (level) {
> +            /*
> +             * if pending bit is not already set for this irq,turn-on the
> +             * pending bit and update the lpi pending table
> +             */
> +            pend |= (1 << (irq % 8));
> +
> +            address_space_write(as, lpipt_baddr + ((irq / 8) * sizeof(pend)),
> +                                 MEMTXATTRS_UNSPECIFIED, &pend, sizeof(pend));
> +        }
> +    }
> +    cs->lpivalid = false;
> +    cs->hpplpi.prio = 0xff;
> +    gicv3_redist_update_lpi(cs);
> +}
> +
> +void gicv3_redist_process_lpi(GICv3CPUState *cs, int irq, int level)
> +{
> +    AddressSpace *as = &cs->gic->dma_as;
> +    uint64_t lpict_baddr;
> +    uint8_t lpite;
> +    uint64_t idbits;
> +
> +    idbits = MIN(FIELD_EX64(cs->gicr_propbaser, GICR_PROPBASER, IDBITS),
> +                 GICD_TYPER_IDBITS);
> +
> +    if ((!cs->gicr_ctlr & GICR_CTLR_ENABLE_LPIS) || !cs->gicr_propbaser ||
> +         !cs->gicr_pendbaser || (idbits < GICR_PROPBASER_IDBITS_THRESHOLD) ||
> +         (irq > (1ULL << (idbits + 1)))) {
> +        return;
> +    }
> +
> +    lpict_baddr = cs->gicr_propbaser & R_GICR_PROPBASER_PHYADDR_MASK;
> +
> +    /* get the lpi config table entry corresponding to this irq */
> +    address_space_read(as, lpict_baddr + ((irq - GICV3_LPI_INTID_START) *
> +                        sizeof(lpite)), MEMTXATTRS_UNSPECIFIED,
> +                        &lpite, sizeof(lpite));
> +
> +    /* check if this irq is enabled before proceeding further */
> +    if (!(lpite & LPI_CTE_ENABLED)) {
> +        return;
> +    }
> +
> +    /* set/clear the pending bit for this irq */
> +    gicv3_redist_lpi_pending(cs, irq, level);
> +
> +    gicv3_redist_update(cs);
> +}
> +
>  void gicv3_redist_set_irq(GICv3CPUState *cs, int irq, int level)
>  {
>      /* Update redistributor state for a change in an external PPI input line */
> diff --git a/hw/intc/gicv3_internal.h b/hw/intc/gicv3_internal.h
> index 91dbe01176..bcbccba573 100644
> --- a/hw/intc/gicv3_internal.h
> +++ b/hw/intc/gicv3_internal.h
> @@ -308,6 +308,13 @@ FIELD(GITS_TYPER, CIL, 36, 1)
>  
>  #define L1TABLE_ENTRY_SIZE         8
>  
> +#define LPI_CTE_ENABLE_OFFSET      0
> +#define LPI_CTE_ENABLED          VALID_MASK
> +#define LPI_CTE_PRIORITY_OFFSET    2
> +#define LPI_CTE_PRIORITY_MASK     ((1U << 6) - 1)
> +#define LPI_PRIORITY_MASK         0xfc
> +#define LPI_SPRIORITY_MASK        0x7e
> +
>  #define GITS_CMDQ_ENTRY_SIZE               32
>  #define NUM_BYTES_IN_DW                     8
>  
> @@ -452,6 +459,9 @@ MemTxResult gicv3_redist_write(void *opaque, hwaddr offset, uint64_t data,
>                                 unsigned size, MemTxAttrs attrs);
>  void gicv3_dist_set_irq(GICv3State *s, int irq, int level);
>  void gicv3_redist_set_irq(GICv3CPUState *cs, int irq, int level);
> +void gicv3_redist_process_lpi(GICv3CPUState *cs, int irq, int level);
> +void gicv3_redist_lpi_pending(GICv3CPUState *cs, int irq, int level);
> +void gicv3_redist_update_lpi(GICv3CPUState *cs);
>  void gicv3_redist_send_sgi(GICv3CPUState *cs, int grp, int irq, bool ns);
>  void gicv3_init_cpuif(GICv3State *s);
>  
> diff --git a/include/hw/intc/arm_gicv3_common.h b/include/hw/intc/arm_gicv3_common.h
> index c1348cc60a..5d839da9c9 100644
> --- a/include/hw/intc/arm_gicv3_common.h
> +++ b/include/hw/intc/arm_gicv3_common.h
> @@ -204,6 +204,16 @@ struct GICv3CPUState {
>       * real state above; it doesn't need to be migrated.
>       */
>      PendingIrq hppi;
> +
> +    /*
> +     * Current highest priority pending lpi for this CPU.
> +     * This is cached information that can be recalculated from the
> +     * real state above; it doesn't need to be migrated.
> +     */
> +    PendingIrq hpplpi;
> +
> +    bool lpivalid; /* current highest priority lpi validity status */
> +
>      /* This is temporary working state, to avoid a malloc in gicv3_update() */
>      bool seenbetter;
>  };>

Thanks

Eric