Re: [PATCH v2] hw/arm/smmuv3: Simplify range invalidation

[Eric Auger]

Hi Liu,

On 8/23/21 9:50 AM, Liu, Renwei wrote:
> Simplify range invalidation which can avoid to iterate over all
> iotlb entries multi-times. For instance invalidations patterns like
> "invalidate 32 4kB pages starting from 0xffacd000" need to iterate over
> all iotlb entries 6 times (num_pages: 1, 2, 16, 8, 4, 1). It only needs
> to iterate over all iotlb entries once with new implementation.

This wouldn't work. This reverts commit
6d9cd115b9df ("hw/arm/smmuv3: Enforce invalidation on a power of two range")
which is mandated for VFIO and virtio to work. IOTLB invalidations must
be naturally aligned and with a power of 2 range, hence this iteration.

Thanks

Eric
>
> Signed-off-by: Renwei Liu <renwei.liu@verisilicon.com>
> ---
> v2:
>  - Remove file mode change.
>
>  hw/arm/smmu-common.c   |  6 +++---
>  hw/arm/smmu-internal.h |  2 +-
>  hw/arm/smmuv3.c        | 22 ++++------------------
>  3 files changed, 8 insertions(+), 22 deletions(-)
>
> diff --git a/hw/arm/smmu-common.c b/hw/arm/smmu-common.c
> index 0459850a93..ccb085f83c 100644
> --- a/hw/arm/smmu-common.c
> +++ b/hw/arm/smmu-common.c
> @@ -142,8 +142,8 @@ static gboolean smmu_hash_remove_by_asid_iova(gpointer 
> key, gpointer value,
>      if (info->asid >= 0 && info->asid != SMMU_IOTLB_ASID(iotlb_key)) {
>          return false;
>      }
> -    return ((info->iova & ~entry->addr_mask) == entry->iova) ||
> -           ((entry->iova & ~info->mask) == info->iova);
> +    return (entry->iova >= info->iova) &&
> +           ((entry->iova + entry->addr_mask) < (info->iova + info->range));
>  }
>  
>  inline void
> @@ -167,7 +167,7 @@ smmu_iotlb_inv_iova(SMMUState *s, int asid, dma_addr_t 
> iova,
>  
>      SMMUIOTLBPageInvInfo info = {
>          .asid = asid, .iova = iova,
> -        .mask = (num_pages * 1 << granule) - 1};
> +        .range = num_pages * 1 << granule};
>  
>      g_hash_table_foreach_remove(s->iotlb,
>                                  smmu_hash_remove_by_asid_iova,
> diff --git a/hw/arm/smmu-internal.h b/hw/arm/smmu-internal.h
> index 2d75b31953..f0e3a777af 100644
> --- a/hw/arm/smmu-internal.h
> +++ b/hw/arm/smmu-internal.h
> @@ -101,7 +101,7 @@ uint64_t iova_level_offset(uint64_t iova, int inputsize,
>  typedef struct SMMUIOTLBPageInvInfo {
>      int asid;
>      uint64_t iova;
> -    uint64_t mask;
> +    uint64_t range;
>  } SMMUIOTLBPageInvInfo;
>  
>  typedef struct SMMUSIDRange {
> diff --git a/hw/arm/smmuv3.c b/hw/arm/smmuv3.c
> index 01b60bee49..0b009107d1 100644
> --- a/hw/arm/smmuv3.c
> +++ b/hw/arm/smmuv3.c
> @@ -857,7 +857,7 @@ static void smmuv3_inv_notifiers_iova(SMMUState *s, int 
> asid, dma_addr_t iova,
>  
>  static void smmuv3_s1_range_inval(SMMUState *s, Cmd *cmd)
>  {
> -    dma_addr_t end, addr = CMD_ADDR(cmd);
> +    dma_addr_t addr = CMD_ADDR(cmd);
>      uint8_t type = CMD_TYPE(cmd);
>      uint16_t vmid = CMD_VMID(cmd);
>      uint8_t scale = CMD_SCALE(cmd);
> @@ -866,7 +866,6 @@ static void smmuv3_s1_range_inval(SMMUState *s, Cmd *cmd)
>      bool leaf = CMD_LEAF(cmd);
>      uint8_t tg = CMD_TG(cmd);
>      uint64_t num_pages;
> -    uint8_t granule;
>      int asid = -1;
>  
>      if (type == SMMU_CMD_TLBI_NH_VA) {
> @@ -880,23 +879,10 @@ static void smmuv3_s1_range_inval(SMMUState *s, Cmd 
> *cmd)
>          return;
>      }
>  
> -    /* RIL in use */
> -
>      num_pages = (num + 1) * BIT_ULL(scale);
> -    granule = tg * 2 + 10;
> -
> -    /* Split invalidations into ^2 range invalidations */
> -    end = addr + (num_pages << granule) - 1;
> -
> -    while (addr != end + 1) {
> -        uint64_t mask = dma_aligned_pow2_mask(addr, end, 64);
> -
> -        num_pages = (mask + 1) >> granule;
> -        trace_smmuv3_s1_range_inval(vmid, asid, addr, tg, num_pages, ttl, 
> leaf);
> -        smmuv3_inv_notifiers_iova(s, asid, addr, tg, num_pages);
> -        smmu_iotlb_inv_iova(s, asid, addr, tg, num_pages, ttl);
> -        addr += mask + 1;
> -    }
> +    trace_smmuv3_s1_range_inval(vmid, asid, addr, tg, num_pages, ttl, leaf);
> +    smmuv3_inv_notifiers_iova(s, asid, addr, tg, num_pages);
> +    smmu_iotlb_inv_iova(s, asid, addr, tg, num_pages, ttl);
>  }
>  
>  static gboolean