Messages in this thread | | | Subject | Re: [PATCH v7 12/23] iommu/smmuv3: Get prepared for nested stage support | From | Robin Murphy <> | Date | Wed, 8 May 2019 15:24:01 +0100 |
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On 08/04/2019 13:19, Eric Auger wrote: > To allow nested stage support, we need to store both > stage 1 and stage 2 configurations (and remove the former > union). > > A nested setup is characterized by both s1_cfg and s2_cfg > set. > > We introduce a new ste.abort field that will be set upon > guest stage1 configuration passing. If s1_cfg is NULL and > ste.abort is set, traffic can't pass. If ste.abort is not set, > S1 is bypassed. > > arm_smmu_write_strtab_ent() is modified to write both stage > fields in the STE and deal with the abort field. > > In nested mode, only stage 2 is "finalized" as the host does > not own/configure the stage 1 context descriptor, guest does. > > Signed-off-by: Eric Auger <eric.auger@redhat.com> > > --- > > v4 -> v5: > - reset ste.abort on detach > > v3 -> v4: > - s1_cfg.nested_abort and nested_bypass removed. > - s/ste.nested/ste.abort > - arm_smmu_write_strtab_ent modifications with introduction > of local abort, bypass and translate local variables > - comment updated > > v1 -> v2: > - invalidate the STE before moving from a live STE config to another > - add the nested_abort and nested_bypass fields > --- > drivers/iommu/arm-smmu-v3.c | 35 ++++++++++++++++++++--------------- > 1 file changed, 20 insertions(+), 15 deletions(-) > > diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c > index 21d027695181..e22e944ffc05 100644 > --- a/drivers/iommu/arm-smmu-v3.c > +++ b/drivers/iommu/arm-smmu-v3.c > @@ -211,6 +211,7 @@ > #define STRTAB_STE_0_CFG_BYPASS 4 > #define STRTAB_STE_0_CFG_S1_TRANS 5 > #define STRTAB_STE_0_CFG_S2_TRANS 6 > +#define STRTAB_STE_0_CFG_NESTED 7 > > #define STRTAB_STE_0_S1FMT GENMASK_ULL(5, 4) > #define STRTAB_STE_0_S1FMT_LINEAR 0 > @@ -514,6 +515,7 @@ struct arm_smmu_strtab_ent { > * configured according to the domain type. > */ > bool assigned; > + bool abort; > struct arm_smmu_s1_cfg *s1_cfg; > struct arm_smmu_s2_cfg *s2_cfg; > }; > @@ -628,10 +630,8 @@ struct arm_smmu_domain { > bool non_strict; > > enum arm_smmu_domain_stage stage; > - union { > - struct arm_smmu_s1_cfg s1_cfg; > - struct arm_smmu_s2_cfg s2_cfg; > - }; > + struct arm_smmu_s1_cfg s1_cfg; > + struct arm_smmu_s2_cfg s2_cfg; > > struct iommu_domain domain; > > @@ -1108,12 +1108,13 @@ static void arm_smmu_write_strtab_ent(struct arm_smmu_device *smmu, u32 sid, > __le64 *dst, struct arm_smmu_strtab_ent *ste) > { > /* > - * This is hideously complicated, but we only really care about > - * three cases at the moment: > + * We care about the following transitions: > * > * 1. Invalid (all zero) -> bypass/fault (init) > - * 2. Bypass/fault -> translation/bypass (attach) > - * 3. Translation/bypass -> bypass/fault (detach) > + * 2. Bypass/fault -> single stage translation/bypass (attach) > + * 3. single stage Translation/bypass -> bypass/fault (detach) > + * 4. S2 -> S1 + S2 (attach_pasid_table) > + * 5. S1 + S2 -> S2 (detach_pasid_table) > * > * Given that we can't update the STE atomically and the SMMU > * doesn't read the thing in a defined order, that leaves us > @@ -1124,7 +1125,7 @@ static void arm_smmu_write_strtab_ent(struct arm_smmu_device *smmu, u32 sid, > * 3. Update Config, sync > */ > u64 val = le64_to_cpu(dst[0]); > - bool ste_live = false; > + bool abort, bypass, translate, ste_live = false; > struct arm_smmu_cmdq_ent prefetch_cmd = { > .opcode = CMDQ_OP_PREFETCH_CFG, > .prefetch = { > @@ -1138,11 +1139,11 @@ static void arm_smmu_write_strtab_ent(struct arm_smmu_device *smmu, u32 sid, > break; > case STRTAB_STE_0_CFG_S1_TRANS: > case STRTAB_STE_0_CFG_S2_TRANS: > + case STRTAB_STE_0_CFG_NESTED: > ste_live = true; > break; > case STRTAB_STE_0_CFG_ABORT: > - if (disable_bypass) > - break; > + break; > default: > BUG(); /* STE corruption */ > } > @@ -1152,8 +1153,13 @@ static void arm_smmu_write_strtab_ent(struct arm_smmu_device *smmu, u32 sid, > val = STRTAB_STE_0_V; > > /* Bypass/fault */ > - if (!ste->assigned || !(ste->s1_cfg || ste->s2_cfg)) { > - if (!ste->assigned && disable_bypass) > + > + abort = (!ste->assigned && disable_bypass) || ste->abort; > + translate = ste->s1_cfg || ste->s2_cfg; > + bypass = !abort && !translate; > + > + if (abort || bypass) { > + if (abort) > val |= FIELD_PREP(STRTAB_STE_0_CFG, STRTAB_STE_0_CFG_ABORT); > else > val |= FIELD_PREP(STRTAB_STE_0_CFG, STRTAB_STE_0_CFG_BYPASS); > @@ -1172,7 +1178,6 @@ static void arm_smmu_write_strtab_ent(struct arm_smmu_device *smmu, u32 sid, > } > > if (ste->s1_cfg) { > - BUG_ON(ste_live);
Hmm, I'm a little uneasy about just removing these checks altogether, as there are still cases where rewriting a live entry is bogus, that we'd really like to keep catching. Is the problem that it's hard to tell when you're 'rewriting' the S2 config of a nested entry with the same thing on attaching/detaching its S1 context?
Robin.
> dst[1] = cpu_to_le64( > FIELD_PREP(STRTAB_STE_1_S1CIR, STRTAB_STE_1_S1C_CACHE_WBRA) | > FIELD_PREP(STRTAB_STE_1_S1COR, STRTAB_STE_1_S1C_CACHE_WBRA) | > @@ -1191,7 +1196,6 @@ static void arm_smmu_write_strtab_ent(struct arm_smmu_device *smmu, u32 sid, > } > > if (ste->s2_cfg) { > - BUG_ON(ste_live); > dst[2] = cpu_to_le64( > FIELD_PREP(STRTAB_STE_2_S2VMID, ste->s2_cfg->vmid) | > FIELD_PREP(STRTAB_STE_2_VTCR, ste->s2_cfg->vtcr) | > @@ -1773,6 +1777,7 @@ static void arm_smmu_detach_dev(struct device *dev) > } > > master->ste.assigned = false; > + master->ste.abort = false; > arm_smmu_install_ste_for_dev(fwspec); > } > >
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