Messages in this thread | | | Date | Thu, 9 Mar 2023 14:28:09 +0000 | Subject | Re: [PATCH v1 12/14] iommu/arm-smmu-v3: Support IOMMU_DOMAIN_NESTED type of allocations | From | Robin Murphy <> |
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On 2023-03-09 13:20, Robin Murphy wrote: > On 2023-03-09 10:53, Nicolin Chen wrote: >> Add domain allocation support for IOMMU_DOMAIN_NESTED type. This includes >> the "finalise" part to log in the user space Stream Table Entry info. >> >> Co-developed-by: Eric Auger <eric.auger@redhat.com> >> Signed-off-by: Eric Auger <eric.auger@redhat.com> >> Signed-off-by: Nicolin Chen <nicolinc@nvidia.com> >> --- >> drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 38 +++++++++++++++++++-- >> 1 file changed, 36 insertions(+), 2 deletions(-) >> >> diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c >> b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c >> index 5ff74edfbd68..1f318b5e0921 100644 >> --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c >> +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c >> @@ -2214,6 +2214,19 @@ static int arm_smmu_domain_finalise(struct >> iommu_domain *domain, >> return 0; >> } >> + if (domain->type == IOMMU_DOMAIN_NESTED) { >> + if (!(smmu->features & ARM_SMMU_FEAT_TRANS_S1) || >> + !(smmu->features & ARM_SMMU_FEAT_TRANS_S2)) { >> + dev_dbg(smmu->dev, "does not implement two stages\n"); >> + return -EINVAL; >> + } >> + smmu_domain->stage = ARM_SMMU_DOMAIN_S1; >> + smmu_domain->s1_cfg.s1fmt = user_cfg->s1fmt; >> + smmu_domain->s1_cfg.s1cdmax = user_cfg->s1cdmax; >> + smmu_domain->s1_cfg.cdcfg.cdtab_dma = user_cfg->s1ctxptr; >> + return 0; > > How's that going to work? If the caller's asked for something we can't > provide, returning something else and hoping it fails later is not > sensible, we should just fail right here. It's even more worrying if > there's a chance it *won't* fail later, and a guest ends up with > "nested" translation giving it full access to host PA space :/
Oops, apologies - in part thanks to the confusing indentation, I managed to miss the early return and misread this all being under the if condition for nesting not being supported. Sorry for the confusion :(
Thanks, Robin.
>> + } >> + >> if (user_cfg_s2 && !(smmu->features & ARM_SMMU_FEAT_TRANS_S2)) >> return -EINVAL; >> if (user_cfg_s2) >> @@ -2863,6 +2876,11 @@ static void arm_smmu_remove_dev_pasid(struct >> device *dev, ioasid_t pasid) >> arm_smmu_sva_remove_dev_pasid(domain, dev, pasid); >> } >> +static const struct iommu_domain_ops arm_smmu_nested_domain_ops = { >> + .attach_dev = arm_smmu_attach_dev, >> + .free = arm_smmu_domain_free, >> +}; >> + >> static struct iommu_domain * >> __arm_smmu_domain_alloc(unsigned type, >> struct arm_smmu_domain *s2, >> @@ -2877,11 +2895,15 @@ __arm_smmu_domain_alloc(unsigned type, >> return arm_smmu_sva_domain_alloc(); >> if (type != IOMMU_DOMAIN_UNMANAGED && >> + type != IOMMU_DOMAIN_NESTED && >> type != IOMMU_DOMAIN_DMA && >> type != IOMMU_DOMAIN_DMA_FQ && >> type != IOMMU_DOMAIN_IDENTITY) >> return NULL; >> + if (s2 && s2->stage != ARM_SMMU_DOMAIN_S2) >> + return NULL; >> + >> /* >> * Allocate the domain and initialise some of its data structures. >> * We can't really finalise the domain unless a master is given. >> @@ -2889,10 +2911,14 @@ __arm_smmu_domain_alloc(unsigned type, >> smmu_domain = kzalloc(sizeof(*smmu_domain), GFP_KERNEL); >> if (!smmu_domain) >> return NULL; >> + smmu_domain->s2 = s2; >> domain = &smmu_domain->domain; >> domain->type = type; >> - domain->ops = arm_smmu_ops.default_domain_ops; >> + if (s2) >> + domain->ops = &arm_smmu_nested_domain_ops; >> + else >> + domain->ops = arm_smmu_ops.default_domain_ops; >> mutex_init(&smmu_domain->init_mutex); >> INIT_LIST_HEAD(&smmu_domain->devices); >> @@ -2923,8 +2949,16 @@ arm_smmu_domain_alloc_user(struct device *dev, >> struct iommu_domain *parent, >> const struct iommu_hwpt_arm_smmuv3 *user_cfg = user_data; >> struct arm_smmu_master *master = dev_iommu_priv_get(dev); >> unsigned type = IOMMU_DOMAIN_UNMANAGED; >> + struct arm_smmu_domain *s2 = NULL; >> + >> + if (parent) { >> + if (parent->ops != arm_smmu_ops.default_domain_ops) >> + return NULL; >> + type = IOMMU_DOMAIN_NESTED; >> + s2 = to_smmu_domain(parent); >> + } >> - return __arm_smmu_domain_alloc(type, NULL, master, user_cfg); >> + return __arm_smmu_domain_alloc(type, s2, master, user_cfg); >> } >> static struct iommu_ops arm_smmu_ops = { >
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