On 2021-08-11 16:00, Will Deacon wrote:
On Wed, Aug 11, 2021 at 11:37:25AM +0530, Sai Prakash Ranjan wrote:
diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.c
b/drivers/iommu/arm/arm-smmu/arm-smmu.c
index f7da8953afbe..3904b598e0f9 100644
--- a/drivers/iommu/arm/arm-smmu/arm-smmu.c
+++ b/drivers/iommu/arm/arm-smmu/arm-smmu.c
@@ -327,9 +327,16 @@ static void arm_smmu_tlb_inv_range_s2(unsigned
long iova, size_t size,
static void arm_smmu_tlb_inv_walk_s1(unsigned long iova, size_t size,
size_t granule, void *cookie)
{
- arm_smmu_tlb_inv_range_s1(iova, size, granule, cookie,
- ARM_SMMU_CB_S1_TLBIVA);
- arm_smmu_tlb_sync_context(cookie);
+ struct arm_smmu_domain *smmu_domain = cookie;
+ struct arm_smmu_cfg *cfg = &smmu_domain->cfg;
+
+ if (cfg->flush_walk_prefer_tlbiasid) {
+ arm_smmu_tlb_inv_context_s1(cookie);
Hmm, this introduces an unconditional wmb() if tlbiasid is preferred. I
think that should be predicated on ARM_SMMU_FEAT_COHERENT_WALK like it
is
for the by-VA ops. Worth doing as a separate patch.
Ok I will keep this as-is for now then.
+ } else {
+ arm_smmu_tlb_inv_range_s1(iova, size, granule, cookie,
+ ARM_SMMU_CB_S1_TLBIVA);
+ arm_smmu_tlb_sync_context(cookie);
+ }
}
static void arm_smmu_tlb_add_page_s1(struct iommu_iotlb_gather
*gather,
@@ -765,8 +772,10 @@ static int arm_smmu_init_domain_context(struct
iommu_domain *domain,
.iommu_dev = smmu->dev,
};
- if (!iommu_get_dma_strict(domain))
+ if (!iommu_get_dma_strict(domain)) {
pgtbl_cfg.quirks |= IO_PGTABLE_QUIRK_NON_STRICT;
+ cfg->flush_walk_prefer_tlbiasid = true;
This is going to interact badly with Robin's series to allow dynamic
transition to non-strict mode, as we don't have a mechanism to switch
over to the by-ASID behaviour. Yes, it should _work_, but it's ugly
having
different TLBI behaviour just because of the how the domain became
non-strict.
Robin -- I think this originated from your idea at [1]. Any idea how to
make
it work with your other series, or shall we drop this part for now and
leave
the TLB invalidation behaviour the same for now?
Will
[1]
https://lore.kernel.org/r/da62ff1c-9b49-34d3-69a1-1a674e4a30f7@xxxxxxx
Right, I think we can drop this non-strict change for now because it
also makes
it a pain to backport it to 5.4/5.10 kernels because of large number of
changes
in dma apis in recent kernels. I will let you and Robin decide if it's
ok to
drop this change and introduce it later with a different patch.
Thanks,
Sai
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