Message ID | 20191209180514.272727-8-jean-philippe@linaro.org |
---|---|
State | Superseded |
Headers | show |
Series | None | expand |
On Tue, Dec 17, 2019 at 05:43:59PM +0100, Auger Eric wrote: > > -static void arm_smmu_write_ctx_desc(struct arm_smmu_device *smmu, > > - struct arm_smmu_s1_cfg *cfg) > > +static int arm_smmu_write_ctx_desc(struct arm_smmu_domain *smmu_domain, > > + int ssid, struct arm_smmu_ctx_desc *cd) > > { > > - u64 val; > > - __le64 *cdptr = cfg->table.ptr; > > - > > /* > > - * We don't need to issue any invalidation here, as we'll invalidate > > - * the STE when installing the new entry anyway. > > + * This function handles the following cases: > > + * > > + * (1) Install primary CD, for normal DMA traffic (SSID = 0). > > + * (2) Install a secondary CD, for SID+SSID traffic. > > + * (3) Update ASID of a CD. Atomically write the first 64 bits of the > > + * CD, then invalidate the old entry and mappings. > > + * (4) Remove a secondary CD. > I see arm_smmu_write_ctx_desc getting called with non null cd in > arm_smmu_attach_dev but I do not see it removed in the detach path? No we don't have to remove the primary CD, since detach clears the STE and frees the CD tables. > > */ > > - val = arm_smmu_cpu_tcr_to_cd(cfg->cd.tcr) | > > -#ifdef __BIG_ENDIAN > > - CTXDESC_CD_0_ENDI | > > -#endif > > - CTXDESC_CD_0_R | CTXDESC_CD_0_A | CTXDESC_CD_0_ASET | > > - CTXDESC_CD_0_AA64 | FIELD_PREP(CTXDESC_CD_0_ASID, cfg->cd.asid) | > > - CTXDESC_CD_0_V; > > + 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;> > > - /* STALL_MODEL==0b10 && CD.S==0 is ILLEGAL */ > > - if (smmu->features & ARM_SMMU_FEAT_STALL_FORCE) > > - val |= CTXDESC_CD_0_S; > > + val = le64_to_cpu(cdptr[0]); > > + cd_live = !!(val & CTXDESC_CD_0_V); > > > > - cdptr[0] = cpu_to_le64(val); > > + if (!cd) { /* (4) */ > > + val = 0; > > + } else if (cd_live) { /* (3) */ > > + val &= ~CTXDESC_CD_0_ASID; > > + val |= FIELD_PREP(CTXDESC_CD_0_ASID, cd->asid); > > + /* > > + * Until CD+TLB invalidation, both ASIDs may be used for tagging > > + * this substream's traffic > > + */ > > + } else { /* (1) and (2) */ > > + cdptr[1] = cpu_to_le64(cd->ttbr & CTXDESC_CD_1_TTB0_MASK); > > + cdptr[2] = 0; > > + cdptr[3] = cpu_to_le64(cd->mair); > > + > > + /* > > + * STE is live, and the SMMU might fetch this CD at any > > + * time. Ensure that it observes the rest of the CD before we > > + * enable it. > Mostly, on't you want the invalid state to be seen? Sorry I didn't get your question. Without the sync, the SMMU could read an invalid address in CD[1], read V=1 in CD[0] and proceed with dereferencing the bogus pointer before seeing our update to CD[1]. To prevent this we follow the update procedure described in IHI0070Ca 3.21.3.1 (Configuration structure update procedure): Because the SMMU can read any reachable structure at any time, and is not required to read the double-words of the structure in order, Arm recommends that the following procedure is used to initialize structures: 1. Structure starts invalid, having V == 0. 2. Fill in all fields, leaving V == 0, then perform a DSB operation to ensure written data is observable from the SMMU. 3. Issue a CMD_CFGI_<STRUCT>, as appropriate. 4. Issue a CMD_SYNC, and wait for completion. 5. Set V to 1, then perform a DSB operation to ensure write is observable by the SMMU. 6. Issue CMD_CFGI_<STRUCT>, as appropriate. 7. Optionally issue a CMD_SYNC, and wait for completion. This must be done if a subsequent software operation, such as enabling device DMA, depends on the SMMU using the new structure. > > @@ -1664,6 +1739,7 @@ static void arm_smmu_write_strtab_ent(struct arm_smmu_master *master, u32 sid, > > if (s1_cfg) { > > BUG_ON(ste_live); > > dst[1] = cpu_to_le64( > > + FIELD_PREP(STRTAB_STE_1_S1DSS, STRTAB_STE_1_S1DSS_SSID0) | > > FIELD_PREP(STRTAB_STE_1_S1CIR, STRTAB_STE_1_S1C_CACHE_WBRA) | > > FIELD_PREP(STRTAB_STE_1_S1COR, STRTAB_STE_1_S1C_CACHE_WBRA) | > > FIELD_PREP(STRTAB_STE_1_S1CSH, ARM_SMMU_SH_ISH) | > > @@ -1674,7 +1750,9 @@ static void arm_smmu_write_strtab_ent(struct arm_smmu_master *master, u32 sid, > > dst[1] |= cpu_to_le64(STRTAB_STE_1_S1STALLD); > > > > val |= (s1_cfg->table.ptr_dma & STRTAB_STE_0_S1CTXPTR_MASK) | > > - FIELD_PREP(STRTAB_STE_0_CFG, STRTAB_STE_0_CFG_S1_TRANS); > > + 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); > Do I understand correctly that each time we update the CD, we also > update the STE. This is not wrong but theoretically this is not needed, > right? Only the primary CD. Once we add SVA (or auxiliary domains) we need to update secondary CDs while the STE is live. This series is just preparation for SVA support. I didn't include the full support because it requires another 25+ patches. > This also explains why you do not need the CMD_PREFETCH_CONFIG with ssid > because you invalidate the config per sid? Hm, I didn't add a CMD_PREFETCH_CONFIG to CDs because I don't know if it's useful. Maybe as future optimization. Thanks, Jean
Hi Jean, On 12/18/19 5:07 PM, Jean-Philippe Brucker wrote: > On Tue, Dec 17, 2019 at 05:43:59PM +0100, Auger Eric wrote: >>> -static void arm_smmu_write_ctx_desc(struct arm_smmu_device *smmu, >>> - struct arm_smmu_s1_cfg *cfg) >>> +static int arm_smmu_write_ctx_desc(struct arm_smmu_domain *smmu_domain, >>> + int ssid, struct arm_smmu_ctx_desc *cd) >>> { >>> - u64 val; >>> - __le64 *cdptr = cfg->table.ptr; >>> - >>> /* >>> - * We don't need to issue any invalidation here, as we'll invalidate >>> - * the STE when installing the new entry anyway. >>> + * This function handles the following cases: >>> + * >>> + * (1) Install primary CD, for normal DMA traffic (SSID = 0). >>> + * (2) Install a secondary CD, for SID+SSID traffic. >>> + * (3) Update ASID of a CD. Atomically write the first 64 bits of the >>> + * CD, then invalidate the old entry and mappings. >>> + * (4) Remove a secondary CD. >> I see arm_smmu_write_ctx_desc getting called with non null cd in >> arm_smmu_attach_dev but I do not see it removed in the detach path? > > No we don't have to remove the primary CD, since detach clears the STE and > frees the CD tables. OK > >>> */ >>> - val = arm_smmu_cpu_tcr_to_cd(cfg->cd.tcr) | >>> -#ifdef __BIG_ENDIAN >>> - CTXDESC_CD_0_ENDI | >>> -#endif >>> - CTXDESC_CD_0_R | CTXDESC_CD_0_A | CTXDESC_CD_0_ASET | >>> - CTXDESC_CD_0_AA64 | FIELD_PREP(CTXDESC_CD_0_ASID, cfg->cd.asid) | >>> - CTXDESC_CD_0_V; >>> + 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;> >>> - /* STALL_MODEL==0b10 && CD.S==0 is ILLEGAL */ >>> - if (smmu->features & ARM_SMMU_FEAT_STALL_FORCE) >>> - val |= CTXDESC_CD_0_S; >>> + val = le64_to_cpu(cdptr[0]); >>> + cd_live = !!(val & CTXDESC_CD_0_V); >>> >>> - cdptr[0] = cpu_to_le64(val); >>> + if (!cd) { /* (4) */ >>> + val = 0; >>> + } else if (cd_live) { /* (3) */ >>> + val &= ~CTXDESC_CD_0_ASID; >>> + val |= FIELD_PREP(CTXDESC_CD_0_ASID, cd->asid); >>> + /* >>> + * Until CD+TLB invalidation, both ASIDs may be used for tagging >>> + * this substream's traffic >>> + */ >>> + } else { /* (1) and (2) */ >>> + cdptr[1] = cpu_to_le64(cd->ttbr & CTXDESC_CD_1_TTB0_MASK); >>> + cdptr[2] = 0; >>> + cdptr[3] = cpu_to_le64(cd->mair); >>> + >>> + /* >>> + * STE is live, and the SMMU might fetch this CD at any >>> + * time. Ensure that it observes the rest of the CD before we >>> + * enable it. >> Mostly, on't you want the invalid state to be seen? Sorry I wanted to say you mostly want to enforce the INVALID bit (what I understand from your below explanations). I was confused by the wording "Ensure that it observes the rest of the CD before we enable it". > > Sorry I didn't get your question. Without the sync, the SMMU could read an > invalid address in CD[1], read V=1 in CD[0] and proceed with dereferencing > the bogus pointer before seeing our update to CD[1]. > > To prevent this we follow the update procedure described in IHI0070Ca > 3.21.3.1 (Configuration structure update procedure): > > Because the SMMU can read any reachable structure at any time, and is not > required to read the double-words of the structure in order, Arm > recommends that the following procedure is used to initialize structures: > 1. Structure starts invalid, having V == 0. > 2. Fill in all fields, leaving V == 0, then perform a DSB operation to > ensure written data is observable from the SMMU. > 3. Issue a CMD_CFGI_<STRUCT>, as appropriate. > 4. Issue a CMD_SYNC, and wait for completion. > 5. Set V to 1, then perform a DSB operation to ensure write is > observable by the SMMU. > 6. Issue CMD_CFGI_<STRUCT>, as appropriate. > 7. Optionally issue a CMD_SYNC, and wait for completion. This must be > done if a subsequent software operation, such as enabling device > DMA, depends on the SMMU using the new structure. > >>> @@ -1664,6 +1739,7 @@ static void arm_smmu_write_strtab_ent(struct arm_smmu_master *master, u32 sid, >>> if (s1_cfg) { >>> BUG_ON(ste_live); >>> dst[1] = cpu_to_le64( >>> + FIELD_PREP(STRTAB_STE_1_S1DSS, STRTAB_STE_1_S1DSS_SSID0) | >>> FIELD_PREP(STRTAB_STE_1_S1CIR, STRTAB_STE_1_S1C_CACHE_WBRA) | >>> FIELD_PREP(STRTAB_STE_1_S1COR, STRTAB_STE_1_S1C_CACHE_WBRA) | >>> FIELD_PREP(STRTAB_STE_1_S1CSH, ARM_SMMU_SH_ISH) | >>> @@ -1674,7 +1750,9 @@ static void arm_smmu_write_strtab_ent(struct arm_smmu_master *master, u32 sid, >>> dst[1] |= cpu_to_le64(STRTAB_STE_1_S1STALLD); >>> >>> val |= (s1_cfg->table.ptr_dma & STRTAB_STE_0_S1CTXPTR_MASK) | >>> - FIELD_PREP(STRTAB_STE_0_CFG, STRTAB_STE_0_CFG_S1_TRANS); >>> + 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); >> Do I understand correctly that each time we update the CD, we also >> update the STE. This is not wrong but theoretically this is not needed, >> right? > > Only the primary CD. Once we add SVA (or auxiliary domains) we need to > update secondary CDs while the STE is live. This series is just > preparation for SVA support. I didn't include the full support because it > requires another 25+ patches. OK > >> This also explains why you do not need the CMD_PREFETCH_CONFIG with ssid >> because you invalidate the config per sid? > > Hm, I didn't add a CMD_PREFETCH_CONFIG to CDs because I don't know if it's > useful. Maybe as future optimization. OK Thanks Eric > > Thanks, > Jean >
diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c index 43d6a7ded6e4..a01071123c34 100644 --- a/drivers/iommu/arm-smmu-v3.c +++ b/drivers/iommu/arm-smmu-v3.c @@ -227,6 +227,11 @@ #define STRTAB_STE_0_S1CTXPTR_MASK GENMASK_ULL(51, 6) #define STRTAB_STE_0_S1CDMAX GENMASK_ULL(63, 59) +#define STRTAB_STE_1_S1DSS GENMASK_ULL(1, 0) +#define STRTAB_STE_1_S1DSS_TERMINATE 0x0 +#define STRTAB_STE_1_S1DSS_BYPASS 0x1 +#define STRTAB_STE_1_S1DSS_SSID0 0x2 + #define STRTAB_STE_1_S1C_CACHE_NC 0UL #define STRTAB_STE_1_S1C_CACHE_WBRA 1UL #define STRTAB_STE_1_S1C_CACHE_WT 2UL @@ -329,6 +334,7 @@ #define CMDQ_PREFETCH_1_SIZE GENMASK_ULL(4, 0) #define CMDQ_PREFETCH_1_ADDR_MASK GENMASK_ULL(63, 12) +#define CMDQ_CFGI_0_SSID GENMASK_ULL(31, 12) #define CMDQ_CFGI_0_SID GENMASK_ULL(63, 32) #define CMDQ_CFGI_1_LEAF (1UL << 0) #define CMDQ_CFGI_1_RANGE GENMASK_ULL(4, 0) @@ -446,8 +452,11 @@ struct arm_smmu_cmdq_ent { #define CMDQ_OP_CFGI_STE 0x3 #define CMDQ_OP_CFGI_ALL 0x4 + #define CMDQ_OP_CFGI_CD 0x5 + #define CMDQ_OP_CFGI_CD_ALL 0x6 struct { u32 sid; + u32 ssid; union { bool leaf; u8 span; @@ -568,6 +577,7 @@ struct arm_smmu_cd_table { struct arm_smmu_s1_cfg { struct arm_smmu_cd_table table; struct arm_smmu_ctx_desc cd; + u8 s1fmt; u8 s1cdmax; }; @@ -860,10 +870,16 @@ static int arm_smmu_cmdq_build_cmd(u64 *cmd, struct arm_smmu_cmdq_ent *ent) cmd[1] |= FIELD_PREP(CMDQ_PREFETCH_1_SIZE, ent->prefetch.size); cmd[1] |= ent->prefetch.addr & CMDQ_PREFETCH_1_ADDR_MASK; break; + case CMDQ_OP_CFGI_CD: + cmd[0] |= FIELD_PREP(CMDQ_CFGI_0_SSID, ent->cfgi.ssid); + /* Fallthrough */ case CMDQ_OP_CFGI_STE: cmd[0] |= FIELD_PREP(CMDQ_CFGI_0_SID, ent->cfgi.sid); cmd[1] |= FIELD_PREP(CMDQ_CFGI_1_LEAF, ent->cfgi.leaf); break; + case CMDQ_OP_CFGI_CD_ALL: + cmd[0] |= FIELD_PREP(CMDQ_CFGI_0_SID, ent->cfgi.sid); + break; case CMDQ_OP_CFGI_ALL: /* Cover the entire SID range */ cmd[1] |= FIELD_PREP(CMDQ_CFGI_1_RANGE, 31); @@ -1456,6 +1472,33 @@ static int arm_smmu_cmdq_issue_sync(struct arm_smmu_device *smmu) } /* Context descriptor manipulation functions */ +static void arm_smmu_sync_cd(struct arm_smmu_domain *smmu_domain, + int ssid, bool leaf) +{ + size_t i; + unsigned long flags; + struct arm_smmu_master *master; + struct arm_smmu_device *smmu = smmu_domain->smmu; + struct arm_smmu_cmdq_ent cmd = { + .opcode = CMDQ_OP_CFGI_CD, + .cfgi = { + .ssid = ssid, + .leaf = leaf, + }, + }; + + spin_lock_irqsave(&smmu_domain->devices_lock, flags); + list_for_each_entry(master, &smmu_domain->devices, domain_head) { + for (i = 0; i < master->num_sids; i++) { + cmd.cfgi.sid = master->sids[i]; + arm_smmu_cmdq_issue_cmd(smmu, &cmd); + } + } + spin_unlock_irqrestore(&smmu_domain->devices_lock, flags); + + arm_smmu_cmdq_issue_sync(smmu); +} + static int arm_smmu_alloc_cd_leaf_table(struct arm_smmu_device *smmu, struct arm_smmu_cd_table *table, size_t num_entries) @@ -1498,34 +1541,65 @@ static u64 arm_smmu_cpu_tcr_to_cd(u64 tcr) return val; } -static void arm_smmu_write_ctx_desc(struct arm_smmu_device *smmu, - struct arm_smmu_s1_cfg *cfg) +static int arm_smmu_write_ctx_desc(struct arm_smmu_domain *smmu_domain, + int ssid, struct arm_smmu_ctx_desc *cd) { - u64 val; - __le64 *cdptr = cfg->table.ptr; - /* - * We don't need to issue any invalidation here, as we'll invalidate - * the STE when installing the new entry anyway. + * This function handles the following cases: + * + * (1) Install primary CD, for normal DMA traffic (SSID = 0). + * (2) Install a secondary CD, for SID+SSID traffic. + * (3) Update ASID of a CD. Atomically write the first 64 bits of the + * CD, then invalidate the old entry and mappings. + * (4) Remove a secondary CD. */ - val = arm_smmu_cpu_tcr_to_cd(cfg->cd.tcr) | -#ifdef __BIG_ENDIAN - CTXDESC_CD_0_ENDI | -#endif - CTXDESC_CD_0_R | CTXDESC_CD_0_A | CTXDESC_CD_0_ASET | - CTXDESC_CD_0_AA64 | FIELD_PREP(CTXDESC_CD_0_ASID, cfg->cd.asid) | - CTXDESC_CD_0_V; + 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; - /* STALL_MODEL==0b10 && CD.S==0 is ILLEGAL */ - if (smmu->features & ARM_SMMU_FEAT_STALL_FORCE) - val |= CTXDESC_CD_0_S; + val = le64_to_cpu(cdptr[0]); + cd_live = !!(val & CTXDESC_CD_0_V); - cdptr[0] = cpu_to_le64(val); + if (!cd) { /* (4) */ + val = 0; + } else if (cd_live) { /* (3) */ + val &= ~CTXDESC_CD_0_ASID; + val |= FIELD_PREP(CTXDESC_CD_0_ASID, cd->asid); + /* + * Until CD+TLB invalidation, both ASIDs may be used for tagging + * this substream's traffic + */ + } else { /* (1) and (2) */ + cdptr[1] = cpu_to_le64(cd->ttbr & CTXDESC_CD_1_TTB0_MASK); + cdptr[2] = 0; + cdptr[3] = cpu_to_le64(cd->mair); + + /* + * STE is live, and the SMMU might fetch this CD at any + * time. Ensure that it observes the rest of the CD before we + * enable it. + */ + arm_smmu_sync_cd(smmu_domain, ssid, true); - val = cfg->cd.ttbr & CTXDESC_CD_1_TTB0_MASK; - cdptr[1] = cpu_to_le64(val); + val = arm_smmu_cpu_tcr_to_cd(cd->tcr) | +#ifdef __BIG_ENDIAN + CTXDESC_CD_0_ENDI | +#endif + CTXDESC_CD_0_R | CTXDESC_CD_0_A | CTXDESC_CD_0_ASET | + CTXDESC_CD_0_AA64 | + FIELD_PREP(CTXDESC_CD_0_ASID, cd->asid) | + CTXDESC_CD_0_V; - cdptr[3] = cpu_to_le64(cfg->cd.mair); + /* STALL_MODEL==0b10 && CD.S==0 is ILLEGAL */ + if (smmu->features & ARM_SMMU_FEAT_STALL_FORCE) + val |= CTXDESC_CD_0_S; + } + + WRITE_ONCE(cdptr[0], cpu_to_le64(val)); + arm_smmu_sync_cd(smmu_domain, ssid, true); + return 0; } static int arm_smmu_alloc_cd_tables(struct arm_smmu_domain *smmu_domain) @@ -1533,6 +1607,7 @@ static int arm_smmu_alloc_cd_tables(struct arm_smmu_domain *smmu_domain) 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); } @@ -1664,6 +1739,7 @@ static void arm_smmu_write_strtab_ent(struct arm_smmu_master *master, u32 sid, if (s1_cfg) { BUG_ON(ste_live); dst[1] = cpu_to_le64( + FIELD_PREP(STRTAB_STE_1_S1DSS, STRTAB_STE_1_S1DSS_SSID0) | FIELD_PREP(STRTAB_STE_1_S1CIR, STRTAB_STE_1_S1C_CACHE_WBRA) | FIELD_PREP(STRTAB_STE_1_S1COR, STRTAB_STE_1_S1C_CACHE_WBRA) | FIELD_PREP(STRTAB_STE_1_S1CSH, ARM_SMMU_SH_ISH) | @@ -1674,7 +1750,9 @@ static void arm_smmu_write_strtab_ent(struct arm_smmu_master *master, u32 sid, dst[1] |= cpu_to_le64(STRTAB_STE_1_S1STALLD); val |= (s1_cfg->table.ptr_dma & STRTAB_STE_0_S1CTXPTR_MASK) | - FIELD_PREP(STRTAB_STE_0_CFG, STRTAB_STE_0_CFG_S1_TRANS); + 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); } if (s2_cfg) { @@ -2479,7 +2557,8 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev) master->ats_enabled = arm_smmu_ats_supported(master); if (smmu_domain->stage == ARM_SMMU_DOMAIN_S1) - arm_smmu_write_ctx_desc(smmu, &smmu_domain->s1_cfg); + arm_smmu_write_ctx_desc(smmu_domain, 0, + &smmu_domain->s1_cfg.cd); arm_smmu_install_ste_for_dev(master);