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Date: Fri, 10 May 2019 16:35:28 +0200
From: Auger Eric <eric.auger@...hat.com>
To: Robin Murphy <robin.murphy@....com>, eric.auger.pro@...il.com,
iommu@...ts.linux-foundation.org, linux-kernel@...r.kernel.org,
kvm@...r.kernel.org, kvmarm@...ts.cs.columbia.edu, joro@...tes.org,
alex.williamson@...hat.com, jacob.jun.pan@...ux.intel.com,
yi.l.liu@...el.com, jean-philippe.brucker@....com,
will.deacon@....com
Cc: kevin.tian@...el.com, ashok.raj@...el.com, marc.zyngier@....com,
christoffer.dall@....com, peter.maydell@...aro.org,
vincent.stehle@....com
Subject: Re: [PATCH v7 13/23] iommu/smmuv3: Implement
attach/detach_pasid_table
Hi Robin,
On 5/8/19 4:38 PM, Robin Murphy wrote:
> On 08/04/2019 13:19, Eric Auger wrote:
>> On attach_pasid_table() we program STE S1 related info set
>> by the guest into the actual physical STEs. At minimum
>> we need to program the context descriptor GPA and compute
>> whether the stage1 is translated/bypassed or aborted.
>>
>> Signed-off-by: Eric Auger <eric.auger@...hat.com>
>>
>> ---
>> v6 -> v7:
>> - check versions and comment the fact we don't need to take
>> into account s1dss and s1fmt
>> v3 -> v4:
>> - adapt to changes in iommu_pasid_table_config
>> - different programming convention at s1_cfg/s2_cfg/ste.abort
>>
>> v2 -> v3:
>> - callback now is named set_pasid_table and struct fields
>> are laid out differently.
>>
>> v1 -> v2:
>> - invalidate the STE before changing them
>> - hold init_mutex
>> - handle new fields
>> ---
>> drivers/iommu/arm-smmu-v3.c | 121 ++++++++++++++++++++++++++++++++++++
>> 1 file changed, 121 insertions(+)
>>
>> diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
>> index e22e944ffc05..1486baf53425 100644
>> --- a/drivers/iommu/arm-smmu-v3.c
>> +++ b/drivers/iommu/arm-smmu-v3.c
>> @@ -2207,6 +2207,125 @@ static void arm_smmu_put_resv_regions(struct
>> device *dev,
>> kfree(entry);
>> }
>> +static int arm_smmu_attach_pasid_table(struct iommu_domain *domain,
>> + struct iommu_pasid_table_config *cfg)
>> +{
>> + struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
>> + struct arm_smmu_master_data *entry;
>> + struct arm_smmu_s1_cfg *s1_cfg;
>> + struct arm_smmu_device *smmu;
>> + unsigned long flags;
>> + int ret = -EINVAL;
>> +
>> + if (cfg->format != IOMMU_PASID_FORMAT_SMMUV3)
>> + return -EINVAL;
>> +
>> + if (cfg->version != PASID_TABLE_CFG_VERSION_1 ||
>> + cfg->smmuv3.version != PASID_TABLE_SMMUV3_CFG_VERSION_1)
>> + return -EINVAL;
>> +
>> + mutex_lock(&smmu_domain->init_mutex);
>> +
>> + smmu = smmu_domain->smmu;
>> +
>> + if (!smmu)
>> + goto out;
>> +
>> + if (!((smmu->features & ARM_SMMU_FEAT_TRANS_S1) &&
>> + (smmu->features & ARM_SMMU_FEAT_TRANS_S2))) {
>> + dev_info(smmu_domain->smmu->dev,
>> + "does not implement two stages\n");
>> + goto out;
>> + }
>
> That check is redundant (and frankly looks a little bit spammy). If the
> one below is not enough, there is a problem elsewhere - if it's possible
> for smmu_domain->stage to ever get set to ARM_SMMU_DOMAIN_NESTED without
> both stages of translation present, we've already gone fundamentally wrong.
Makes sense. Moved that check to arm_smmu_domain_finalise() instead and
remove redundant ones.
>
>> +
>> + if (smmu_domain->stage != ARM_SMMU_DOMAIN_NESTED)
>> + goto out;
>> +
>> + switch (cfg->config) {
>> + case IOMMU_PASID_CONFIG_ABORT:
>> + spin_lock_irqsave(&smmu_domain->devices_lock, flags);
>> + list_for_each_entry(entry, &smmu_domain->devices, list) {
>> + entry->ste.s1_cfg = NULL;
>> + entry->ste.abort = true;
>> + arm_smmu_install_ste_for_dev(entry->dev->iommu_fwspec);
>> + }
>> + spin_unlock_irqrestore(&smmu_domain->devices_lock, flags);
>> + ret = 0;
>> + break;
>> + case IOMMU_PASID_CONFIG_BYPASS:
>> + spin_lock_irqsave(&smmu_domain->devices_lock, flags);
>> + list_for_each_entry(entry, &smmu_domain->devices, list) {
>> + entry->ste.s1_cfg = NULL;
>> + entry->ste.abort = false;
>> + arm_smmu_install_ste_for_dev(entry->dev->iommu_fwspec);
>> + }
>> + spin_unlock_irqrestore(&smmu_domain->devices_lock, flags);
>> + ret = 0;
>> + break;
>> + case IOMMU_PASID_CONFIG_TRANSLATE:
>> + /*
>> + * we currently support a single CD so s1fmt and s1dss
>> + * fields are also ignored
>> + */
>> + if (cfg->pasid_bits)
>> + goto out;
>> +
>> + s1_cfg = &smmu_domain->s1_cfg;
>> + s1_cfg->cdptr_dma = cfg->base_ptr;
>> +
>> + spin_lock_irqsave(&smmu_domain->devices_lock, flags);
>> + list_for_each_entry(entry, &smmu_domain->devices, list) {
>> + entry->ste.s1_cfg = s1_cfg;
>
> Either we reject valid->valid transitions outright, or we need to remove
> and invalidate the existing S1 context from the STE at this point, no?
I agree. I added this in arm_smmu_write_strtab_ent().
>
>> + entry->ste.abort = false;
>> + arm_smmu_install_ste_for_dev(entry->dev->iommu_fwspec);
>> + }
>> + spin_unlock_irqrestore(&smmu_domain->devices_lock, flags);
>> + ret = 0;
>> + break;
>> + default:
>> + break;
>> + }
>> +out:
>> + mutex_unlock(&smmu_domain->init_mutex);
>> + return ret;
>> +}
>> +
>> +static void arm_smmu_detach_pasid_table(struct iommu_domain *domain)
>> +{
>> + struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
>> + struct arm_smmu_master_data *entry;
>> + struct arm_smmu_device *smmu;
>> + unsigned long flags;
>> +
>> + mutex_lock(&smmu_domain->init_mutex);
>> +
>> + smmu = smmu_domain->smmu;
>> +
>> + if (!smmu)
>> + return;
>> +
>> + if (!((smmu->features & ARM_SMMU_FEAT_TRANS_S1) &&
>> + (smmu->features & ARM_SMMU_FEAT_TRANS_S2))) {
>> + dev_info(smmu_domain->smmu->dev,
>> + "does not implement two stages\n");
>> + return;
>> + }
>
> Same comment as before.
OK
Thanks
Eric
>
> Robin.
>
>> +
>> + if (smmu_domain->stage != ARM_SMMU_DOMAIN_NESTED)
>> + return;
>> +
>> + spin_lock_irqsave(&smmu_domain->devices_lock, flags);
>> + list_for_each_entry(entry, &smmu_domain->devices, list) {
>> + entry->ste.s1_cfg = NULL;
>> + entry->ste.abort = true;
>> + arm_smmu_install_ste_for_dev(entry->dev->iommu_fwspec);
>> + }
>> + spin_unlock_irqrestore(&smmu_domain->devices_lock, flags);
>> +
>> + memset(&smmu_domain->s1_cfg, 0, sizeof(struct arm_smmu_s1_cfg));
>> + mutex_unlock(&smmu_domain->init_mutex);
>> +}
>> +
>> static struct iommu_ops arm_smmu_ops = {
>> .capable = arm_smmu_capable,
>> .domain_alloc = arm_smmu_domain_alloc,
>> @@ -2225,6 +2344,8 @@ static struct iommu_ops arm_smmu_ops = {
>> .of_xlate = arm_smmu_of_xlate,
>> .get_resv_regions = arm_smmu_get_resv_regions,
>> .put_resv_regions = arm_smmu_put_resv_regions,
>> + .attach_pasid_table = arm_smmu_attach_pasid_table,
>> + .detach_pasid_table = arm_smmu_detach_pasid_table,
>> .pgsize_bitmap = -1UL, /* Restricted during device attach */
>> };
>>
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