[PATCH v7 17/24] iommu/arm-smmu-v3: Hook up ATC invalidation to mm ops

Jean-Philippe Brucker
2020-05-19T18:07:38Z

The invalidate_range() notifier is called for any change to the address
space. Perform the required ATC invalidations.

Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
---
v6->v7: invalidate() doesn't need RCU protection anymore.
---
drivers/iommu/arm-smmu-v3.c | 29 +++++++++++++++++++++++------
1 file changed, 23 insertions(+), 6 deletions(-)

diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
index 00a9342eed99..1386d4d2bc60 100644
--- a/drivers/iommu/arm-smmu-v3.c
+++ b/drivers/iommu/arm-smmu-v3.c
@@ -2392,6 +2392,20 @@ arm_smmu_atc_inv_to_cmd(int ssid, unsigned long iova, size_t size,
size_t inval_grain_shift = 12;
unsigned long page_start, page_end;

+ /*
+ * ATS and PASID:
+ *
+ * If substream_valid is clear, the PCIe TLP is sent without a PASID
+ * prefix. In that case all ATC entries within the address range are
+ * invalidated, including those that were requested with a PASID! There
+ * is no way to invalidate only entries without PASID.
+ *
+ * When using STRTAB_STE_1_S1DSS_SSID0 (reserving CD 0 for non-PASID
+ * traffic), translation requests without PASID create ATC entries
+ * without PASID, which must be invalidated with substream_valid clear.
+ * This has the unpleasant side-effect of invalidating all PASID-tagged
+ * ATC entries within the address range.
+ */
*cmd = (struct arm_smmu_cmdq_ent) {
.opcode = CMDQ_OP_ATC_INV,
.substream_valid = !!ssid,
@@ -2435,12 +2449,12 @@ arm_smmu_atc_inv_to_cmd(int ssid, unsigned long iova, size_t size,
cmd->atc.size = log2_span;
}

-static int arm_smmu_atc_inv_master(struct arm_smmu_master *master)
+static int arm_smmu_atc_inv_master(struct arm_smmu_master *master, int ssid)
{
int i;
struct arm_smmu_cmdq_ent cmd;

- arm_smmu_atc_inv_to_cmd(0, 0, 0, &cmd);
+ arm_smmu_atc_inv_to_cmd(ssid, 0, 0, &cmd);

for (i = 0; i < master->num_sids; i++) {
cmd.atc.sid = master->sids[i];
@@ -2968,7 +2982,7 @@ static void arm_smmu_disable_ats(struct arm_smmu_master *master)
* ATC invalidation via the SMMU.
*/
wmb();
- arm_smmu_atc_inv_master(master);
+ arm_smmu_atc_inv_master(master, 0);
atomic_dec(&smmu_domain->nr_ats_masters);
}

@@ -3169,7 +3183,10 @@ static void arm_smmu_mm_invalidate_range(struct mmu_notifier *mn,
struct mm_struct *mm,
unsigned long start, unsigned long end)
{
- /* TODO: invalidate ATS */
+ struct arm_smmu_mmu_notifier *smmu_mn = mn_to_smmu(mn);
+
+ arm_smmu_atc_inv_domain(smmu_mn->domain, mm->pasid, start,
+ end - start + 1);
}

static void arm_smmu_mm_release(struct mmu_notifier *mn, struct mm_struct *mm)
@@ -3190,7 +3207,7 @@ static void arm_smmu_mm_release(struct mmu_notifier *mn, struct mm_struct *mm)
arm_smmu_write_ctx_desc(smmu_domain, mm->pasid, &invalid_cd);

arm_smmu_tlb_inv_asid(smmu_domain->smmu, smmu_mn->cd->asid);
- /* TODO: invalidate ATS */
+ arm_smmu_atc_inv_domain(smmu_domain, mm->pasid, 0, 0);

smmu_mn->cleared = true;
mutex_unlock(&sva_lock);
@@ -3281,7 +3298,7 @@ void arm_smmu_mmu_notifier_put(struct arm_smmu_mmu_notifier *smmu_mn)
*/
if (!smmu_mn->cleared) {
arm_smmu_tlb_inv_asid(smmu_domain->smmu, cd->asid);
- /* TODO: invalidate ATS */
+ arm_smmu_atc_inv_domain(smmu_domain, mm->pasid, 0, 0);
}

/* Frees smmu_mn */