Hi Jean,
On 12/9/19 7:05 PM, Jean-Philippe Brucker wrote:
> The SMMU can support up to 20 bits of SSID. Add a second level of page
> tables to accommodate this. Devices that support more than 1024 SSIDs now
> have a table of 1024 L1 entries (8kB), pointing to tables of 1024 context
> descriptors (64kB), allocated on demand.
>
> Signed-off-by: Jean-Philippe Brucker <jean-phili...@linaro.org>
> ---
> drivers/iommu/arm-smmu-v3.c | 153 +++++++++++++++++++++++++++++++++---
> 1 file changed, 143 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
> index fc5119f34187..52adcdfda58b 100644
> --- a/drivers/iommu/arm-smmu-v3.c
> +++ b/drivers/iommu/arm-smmu-v3.c
> @@ -224,6 +224,7 @@
>
> #define STRTAB_STE_0_S1FMT GENMASK_ULL(5, 4)
> #define STRTAB_STE_0_S1FMT_LINEAR 0
> +#define STRTAB_STE_0_S1FMT_64K_L2 2
> #define STRTAB_STE_0_S1CTXPTR_MASK GENMASK_ULL(51, 6)
> #define STRTAB_STE_0_S1CDMAX GENMASK_ULL(63, 59)
>
> @@ -263,7 +264,20 @@
>
> #define STRTAB_STE_3_S2TTB_MASK GENMASK_ULL(51, 4)
>
> -/* Context descriptor (stage-1 only) */
> +/*
> + * Context descriptors.
> + *
> + * Linear: when less than 1024 SSIDs are supported
> + * 2lvl: at most 1024 L1 entries,
> + * 1024 lazy entries per table.
> + */
> +#define CTXDESC_SPLIT 10
> +#define CTXDESC_L2_ENTRIES (1 << CTXDESC_SPLIT)
> +
> +#define CTXDESC_L1_DESC_DWORDS 1
> +#define CTXDESC_L1_DESC_VALID 1
> +#define CTXDESC_L1_DESC_L2PTR_MASK GENMASK_ULL(51, 12)
> +
> #define CTXDESC_CD_DWORDS 8
> #define CTXDESC_CD_0_TCR_T0SZ GENMASK_ULL(5, 0)
> #define ARM64_TCR_T0SZ GENMASK_ULL(5, 0)
> @@ -575,7 +589,10 @@ struct arm_smmu_cd_table {
> };
>
> struct arm_smmu_s1_cfg {
> - struct arm_smmu_cd_table table;
> + struct arm_smmu_cd_table *tables;
> + size_t num_tables;
> + __le64 *l1ptr;
you may add a comment saying that l1ptr and l1ptr_dma are only set/used
in non linear case and one comment saying that "tables" represent leaf
tables.
> + dma_addr_t l1ptr_dma;
> struct arm_smmu_ctx_desc cd;
> u8 s1fmt;
> u8 s1cdmax;
> @@ -1521,9 +1538,53 @@ static void arm_smmu_free_cd_leaf_table(struct
> arm_smmu_device *smmu,
> {
> size_t size = num_entries * (CTXDESC_CD_DWORDS << 3);
>
> + if (!table->ptr)
> + return;
> dmam_free_coherent(smmu->dev, size, table->ptr, table->ptr_dma);
> }
>
> +static void arm_smmu_write_cd_l1_desc(__le64 *dst,
> + struct arm_smmu_cd_table *table)
> +{
> + u64 val = (table->ptr_dma & CTXDESC_L1_DESC_L2PTR_MASK) |
> + CTXDESC_L1_DESC_VALID;
> +
> + WRITE_ONCE(*dst, cpu_to_le64(val));
> +}
> +
> +static __le64 *arm_smmu_get_cd_ptr(struct arm_smmu_domain *smmu_domain,
> + u32 ssid)
> +{
> + __le64 *l1ptr;
> + unsigned int idx;
> + struct arm_smmu_cd_table *table;
> + struct arm_smmu_device *smmu = smmu_domain->smmu;
> + struct arm_smmu_s1_cfg *cfg = &smmu_domain->s1_cfg;
> +
> + if (cfg->s1fmt == STRTAB_STE_0_S1FMT_LINEAR) {
> + table = &cfg->tables[0];
> + idx = ssid;
> + } else {
nit: you may avoid this extra indent by either returning above or go to
a label.
> + idx = ssid >> CTXDESC_SPLIT;
> + if (idx >= cfg->num_tables)
> + return NULL;
> +
> + table = &cfg->tables[idx];
> + if (!table->ptr) {
> + if (arm_smmu_alloc_cd_leaf_table(smmu, table,
> + CTXDESC_L2_ENTRIES))
> + return NULL;
> +
> + l1ptr = cfg->l1ptr + idx * CTXDESC_L1_DESC_DWORDS;
> + arm_smmu_write_cd_l1_desc(l1ptr, table);
> + /* An invalid L1CD can be cached */
> + arm_smmu_sync_cd(smmu_domain, ssid, false);
> + }
> + idx = ssid & (CTXDESC_L2_ENTRIES - 1);
> + }
> + return table->ptr + idx * CTXDESC_CD_DWORDS;> +}
> +
> static u64 arm_smmu_cpu_tcr_to_cd(u64 tcr)
> {
> u64 val = 0;
> @@ -1556,8 +1617,10 @@ static int arm_smmu_write_ctx_desc(struct
> arm_smmu_domain *smmu_domain,
> u64 val;
> bool cd_live;
> struct arm_smmu_device *smmu = smmu_domain->smmu;
> - __le64 *cdptr = smmu_domain->s1_cfg.table.ptr + ssid *
> - CTXDESC_CD_DWORDS;
> + __le64 *cdptr = arm_smmu_get_cd_ptr(smmu_domain, ssid);
> +
> + if (!cdptr)
> + return -ENOMEM;
-ENOMEM does not fit well with (idx >= cfg->num_tables) case
Besides the idx is checked against the max table capacity only in non
linear mode. Can't you check the ssid against cfg->s1cdmax earlier?
>
> val = le64_to_cpu(cdptr[0]);
> cd_live = !!(val & CTXDESC_CD_0_V);
> @@ -1604,20 +1667,87 @@ static int arm_smmu_write_ctx_desc(struct
> arm_smmu_domain *smmu_domain,
>
> static int arm_smmu_alloc_cd_tables(struct arm_smmu_domain *smmu_domain)
> {
> + int ret;
> + size_t size = 0;
> + size_t max_contexts;
> struct arm_smmu_device *smmu = smmu_domain->smmu;
> struct arm_smmu_s1_cfg *cfg = &smmu_domain->s1_cfg;
>
> - cfg->s1fmt = STRTAB_STE_0_S1FMT_LINEAR;
> - return arm_smmu_alloc_cd_leaf_table(smmu, &cfg->table,
> - 1 << cfg->s1cdmax);
> + max_contexts = 1 << cfg->s1cdmax;
> +
> + if (!(smmu->features & ARM_SMMU_FEAT_2_LVL_CDTAB) ||
> + max_contexts <= CTXDESC_L2_ENTRIES) {
> + cfg->s1fmt = STRTAB_STE_0_S1FMT_LINEAR;
> + cfg->num_tables = 1;
> + } else {
> + cfg->s1fmt = STRTAB_STE_0_S1FMT_64K_L2;
> + cfg->num_tables = DIV_ROUND_UP(max_contexts,
> + CTXDESC_L2_ENTRIES);
> +
> + size = cfg->num_tables * (CTXDESC_L1_DESC_DWORDS << 3);
> + cfg->l1ptr = dmam_alloc_coherent(smmu->dev, size,
> + &cfg->l1ptr_dma,
> + GFP_KERNEL);
> + if (!cfg->l1ptr) {
> + dev_warn(smmu->dev,
> + "failed to allocate L1 context table\n");
> + return -ENOMEM;
> + }
> + }
> +
> + cfg->tables = devm_kzalloc(smmu->dev, sizeof(struct arm_smmu_cd_table) *
> + cfg->num_tables, GFP_KERNEL);
> + if (!cfg->tables) {
> + ret = -ENOMEM;
> + goto err_free_l1;
> + }
> +
> + /*
> + * Only allocate a leaf table for linear case. With two levels, leaf
> + * tables are allocated lazily.
> + */
> + if (!cfg->l1ptr) {
> + ret = arm_smmu_alloc_cd_leaf_table(smmu, &cfg->tables[0],
> + max_contexts);
> + if (ret)
> + goto err_free_tables;
> + }
> +
> + return 0;
> +
> +err_free_tables:
> + devm_kfree(smmu->dev, cfg->tables);
> + cfg->tables = NULL;
> +err_free_l1:
> + if (cfg->l1ptr) {
> + dmam_free_coherent(smmu->dev, size, cfg->l1ptr, cfg->l1ptr_dma);
> + cfg->l1ptr = NULL;
> + cfg->l1ptr_dma = 0;
> + }
> + return ret;
> }
>
> static void arm_smmu_free_cd_tables(struct arm_smmu_domain *smmu_domain)
> {
> + int i;
> struct arm_smmu_device *smmu = smmu_domain->smmu;
> struct arm_smmu_s1_cfg *cfg = &smmu_domain->s1_cfg;
> + size_t num_leaf_entries = 1 << cfg->s1cdmax;
> + struct arm_smmu_cd_table *table = cfg->tables;
> +
> + if (cfg->l1ptr) {
> + size_t size = cfg->num_tables * (CTXDESC_L1_DESC_DWORDS << 3);
>
> - arm_smmu_free_cd_leaf_table(smmu, &cfg->table, 1 << cfg->s1cdmax);
> + dmam_free_coherent(smmu->dev, size, cfg->l1ptr, cfg->l1ptr_dma);
> + cfg->l1ptr = NULL;
> + cfg->l1ptr_dma = 0;
> + num_leaf_entries = CTXDESC_L2_ENTRIES;
> + }
> +
> + for (i = 0; i < cfg->num_tables; i++, table++)
> + arm_smmu_free_cd_leaf_table(smmu, table, num_leaf_entries);
> + devm_kfree(smmu->dev, cfg->tables);
> + cfg->tables = NULL;
> }
>
> /* Stream table manipulation functions */
> @@ -1737,6 +1867,9 @@ static void arm_smmu_write_strtab_ent(struct
> arm_smmu_master *master, u32 sid,
> }
>
> if (s1_cfg) {
> + dma_addr_t ptr_dma = s1_cfg->l1ptr ? s1_cfg->l1ptr_dma :
> + s1_cfg->tables[0].ptr_dma;
> +
> BUG_ON(ste_live);
> dst[1] = cpu_to_le64(
> FIELD_PREP(STRTAB_STE_1_S1DSS,
> STRTAB_STE_1_S1DSS_SSID0) |
> @@ -1749,7 +1882,7 @@ static void arm_smmu_write_strtab_ent(struct
> arm_smmu_master *master, u32 sid,
> !(smmu->features & ARM_SMMU_FEAT_STALL_FORCE))
> dst[1] |= cpu_to_le64(STRTAB_STE_1_S1STALLD);
>
> - val |= (s1_cfg->table.ptr_dma & STRTAB_STE_0_S1CTXPTR_MASK) |
> + val |= (ptr_dma & STRTAB_STE_0_S1CTXPTR_MASK) |
> FIELD_PREP(STRTAB_STE_0_CFG, STRTAB_STE_0_CFG_S1_TRANS)
> |
> FIELD_PREP(STRTAB_STE_0_S1CDMAX, s1_cfg->s1cdmax) |
> FIELD_PREP(STRTAB_STE_0_S1FMT, s1_cfg->s1fmt);
> @@ -2265,7 +2398,7 @@ static void arm_smmu_domain_free(struct iommu_domain
> *domain)
> if (smmu_domain->stage == ARM_SMMU_DOMAIN_S1) {
> struct arm_smmu_s1_cfg *cfg = &smmu_domain->s1_cfg;
>
> - if (cfg->table.ptr) {
> + if (cfg->tables) {
> arm_smmu_free_cd_tables(smmu_domain);
> arm_smmu_bitmap_free(smmu->asid_map, cfg->cd.asid);
> }
>
Otherwise looks good to me.
Thanks
Eric
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