Hi Mostafa,
On 4/29/24 05:23, Mostafa Saleh wrote:
> In the previous patch, comine_tlb() was added which combines 2 TLB
> entries into one, which chooses the granule and level from the
> smallest entry.
>
> This means that a nested translation, an entry can be cached with the
> granule of stage-2 and not stage-1.
>
> However, the lookup for an IOVA in nested configuration is done with
> stage-1 granule, this patch reworks lookup in that case, so it falls
> back to stage-2 granule if no entry is found using stage-1 granule.
>
> Signed-off-by: Mostafa Saleh <smost...@google.com>
> ---
> hw/arm/smmu-common.c | 24 ++++++++++++++++++++++--
> 1 file changed, 22 insertions(+), 2 deletions(-)
>
> diff --git a/hw/arm/smmu-common.c b/hw/arm/smmu-common.c
> index 0d6945fa54..c67af3bc6d 100644
> --- a/hw/arm/smmu-common.c
> +++ b/hw/arm/smmu-common.c
> @@ -66,8 +66,10 @@ SMMUIOTLBKey smmu_get_iotlb_key(int asid, int vmid,
> uint64_t iova,
> return key;
> }
>
> -SMMUTLBEntry *smmu_iotlb_lookup(SMMUState *bs, SMMUTransCfg *cfg,
> - SMMUTransTableInfo *tt, hwaddr iova)
> +static SMMUTLBEntry *smmu_iotlb_lookup_all_levels(SMMUState *bs,
> + SMMUTransCfg *cfg,
> + SMMUTransTableInfo *tt,
> + hwaddr iova)
> {
> uint8_t tg = (tt->granule_sz - 10) / 2;
> uint8_t inputsize = 64 - tt->tsz;
> @@ -88,6 +90,24 @@ SMMUTLBEntry *smmu_iotlb_lookup(SMMUState *bs,
> SMMUTransCfg *cfg,
> }
> level++;
> }
> + return entry;
> +}
> +
> +SMMUTLBEntry *smmu_iotlb_lookup(SMMUState *bs, SMMUTransCfg *cfg,
> + SMMUTransTableInfo *tt, hwaddr iova)
> +{
> + SMMUTLBEntry *entry = NULL;
> +
> + entry = smmu_iotlb_lookup_all_levels(bs, cfg, tt, iova);
> + /*
> + * For nested translation also try the s2 granule, as the TLB will insert
> + * it if the size of s2 tlb entry was smaller.
> + */
> + if (!entry && (cfg->stage == SMMU_NESTED) &&
> + (cfg->s2cfg.granule_sz != tt->granule_sz)) {
> + tt->granule_sz = cfg->s2cfg.granule_sz;
is it safe to alter the tt->granule_sz without restoring it? In the
positive I think this would deserve a comment.
Eric
> + entry = smmu_iotlb_lookup_all_levels(bs, cfg, tt, iova);
> + }
>
> if (entry) {
> cfg->iotlb_hits++;
