Re: [PATCH 3/3] hw/riscv/riscv_iommu: Remove the "bus" property

[Alistair Francis <alistair23@gmail.com>]

On Sun, Mar 2, 2025 at 7:13 PM Jason Chien <jason.chien@sifive.com> wrote:
>
> This property was originally intended to set the bus number for non-root
> endpoints. However, since the PCIe bus number is assigned and modified
> at runtime, setting this property before software execution is incorrect.
> Additionally, the property incorrectly assumes that all endpoints share
> the same bus, whereas no such restriction exists.
>
> With the IOMMU now retrieving the latest device IDs from memory attributes,
> there is no longer a need to set or update device IDs.
>
> Signed-off-by: Jason Chien <jason.chien@sifive.com>

Acked-by: Alistair Francis <alistair.francis@wdc.com>

Alistair

> ---
>  hw/riscv/riscv-iommu.c | 7 -------
>  hw/riscv/riscv-iommu.h | 1 -
>  2 files changed, 8 deletions(-)
>
> diff --git a/hw/riscv/riscv-iommu.c b/hw/riscv/riscv-iommu.c
> index b72ce8e6d0..1ca85b95ac 100644
> --- a/hw/riscv/riscv-iommu.c
> +++ b/hw/riscv/riscv-iommu.c
> @@ -1197,9 +1197,6 @@ static AddressSpace *riscv_iommu_space(RISCVIOMMUState *s, uint32_t devid)
>  {
>      RISCVIOMMUSpace *as;
>
> -    /* FIXME: PCIe bus remapping for attached endpoints. */
> -    devid |= s->bus << 8;
> -
>      QLIST_FOREACH(as, &s->spaces, list) {
>          if (as->devid == devid) {
>              break;
> @@ -2261,9 +2258,6 @@ static MemTxResult riscv_iommu_trap_write(void *opaque, hwaddr addr,
>          return MEMTX_ACCESS_ERROR;
>      }
>
> -    /* FIXME: PCIe bus remapping for attached endpoints. */
> -    devid |= s->bus << 8;
> -
>      ctx = riscv_iommu_ctx(s, devid, 0, &ref);
>      if (ctx == NULL) {
>          res = MEMTX_ACCESS_ERROR;
> @@ -2498,7 +2492,6 @@ void riscv_iommu_reset(RISCVIOMMUState *s)
>  static const Property riscv_iommu_properties[] = {
>      DEFINE_PROP_UINT32("version", RISCVIOMMUState, version,
>          RISCV_IOMMU_SPEC_DOT_VER),
> -    DEFINE_PROP_UINT32("bus", RISCVIOMMUState, bus, 0x0),
>      DEFINE_PROP_UINT32("ioatc-limit", RISCVIOMMUState, iot_limit,
>          LIMIT_CACHE_IOT),
>      DEFINE_PROP_BOOL("intremap", RISCVIOMMUState, enable_msi, TRUE),
> diff --git a/hw/riscv/riscv-iommu.h b/hw/riscv/riscv-iommu.h
> index a31aa62144..655c0e71a8 100644
> --- a/hw/riscv/riscv-iommu.h
> +++ b/hw/riscv/riscv-iommu.h
> @@ -34,7 +34,6 @@ struct RISCVIOMMUState {
>      /*< public >*/
>      uint32_t version;     /* Reported interface version number */
>      uint32_t pid_bits;    /* process identifier width */
> -    uint32_t bus;         /* PCI bus mapping for non-root endpoints */
>
>      uint64_t cap;         /* IOMMU supported capabilities */
>      uint64_t fctl;        /* IOMMU enabled features */
> --
> 2.43.2
>
>