Re: [RFC PATCH 02/10] iommu/vt-d: Alloc domain for a mediated device

From: Lu Baolu
Date: Mon Jul 23 2018 - 22:10:22 EST


Hi,

On 07/23/2018 12:44 PM, Liu, Yi L wrote:
>> From: Lu Baolu [mailto:baolu.lu@xxxxxxxxxxxxxxx]
>> Sent: Sunday, July 22, 2018 2:09 PM
>>
>> The PASID-granular 2nd level address translation makes it possible to isolate and
>> protect a mediated device exposed by a real device which support PCI PASID
> "support" -> "supports"

Sure.

>
>> features. This patch adds support to allocate a domain for a mediated device. A
>> default pasid value will be allocated as well for the mediated device. This will be used
> This is not accurate, it is "a default pasid value will be allocated for the domain, and the
> mdev will be configed to use this pasid when it is added to this domain"

Looks better. Thank you.

Best regards,
Lu Baolu

>
> Regards,
> Yi Liu
>
>> by the mediated device attached to this domain for non-SVM DMA transactions.
>>
>> Cc: Ashok Raj <ashok.raj@xxxxxxxxx>
>> Cc: Jacob Pan <jacob.jun.pan@xxxxxxxxxxxxxxx>
>> Cc: Kevin Tian <kevin.tian@xxxxxxxxx>
>> Cc: Liu Yi L <yi.l.liu@xxxxxxxxx>
>> Signed-off-by: Sanjay Kumar <sanjay.k.kumar@xxxxxxxxx>
>> Signed-off-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
>> ---
>> drivers/iommu/intel-iommu.c | 17 ++++++++++++++++- include/linux/intel-iommu.h
>> | 5 +++++
>> 2 files changed, 21 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c index
>> fc3ac1c..3ede34a 100644
>> --- a/drivers/iommu/intel-iommu.c
>> +++ b/drivers/iommu/intel-iommu.c
>> @@ -1926,6 +1926,9 @@ static void domain_exit(struct dmar_domain *domain)
>> domain_remove_dev_info(domain);
>> rcu_read_unlock();
>>
>> + if (domain->default_pasid > 0)
>> + intel_pasid_free_id(domain->default_pasid);
>> +
>> /* destroy iovas */
>> put_iova_domain(&domain->iovad);
>>
>> @@ -2519,11 +2522,23 @@ static struct dmar_domain
>> *dmar_insert_one_dev_info(struct intel_iommu *iommu,
>> }
>> }
>>
>> + if (dev && dev_is_mdev(dev) && domain->default_pasid <= 0) {
>> + int max = intel_pasid_get_dev_max_id(dev_mdev_parent(dev));
>> +
>> + domain->default_pasid = intel_pasid_alloc_id(domain, PASID_MIN,
>> + max, GFP_KERNEL);
>> + if (domain->default_pasid < 0) {
>> + free_devinfo_mem(info);
>> + return NULL;
>> + }
>> + }
>> +
>> spin_lock_irqsave(&device_domain_lock, flags);
>> if (dev)
>> found = find_domain(dev);
>>
>> - if (!found) {
>> + /* A mediated device never has an DMA alias. Ignore searching. */
>> + if (!found && !dev_is_mdev(dev)) {
>> struct device_domain_info *info2;
>> info2 = dmar_search_domain_by_dev_info(iommu->segment, bus,
>> devfn);
>> if (info2) {
>> diff --git a/include/linux/intel-iommu.h b/include/linux/intel-iommu.h index
>> 7efc632..9f5dcf6 100644
>> --- a/include/linux/intel-iommu.h
>> +++ b/include/linux/intel-iommu.h
>> @@ -423,6 +423,11 @@ struct dmar_domain {
>> 2 == 1GiB, 3 == 512GiB, 4 == 1TiB */
>> u64 max_addr; /* maximum mapped address */
>>
>> + int default_pasid; /*
>> + * The default pasid used for non-SVM
>> + * traffic on mediated devices.
>> + */
>> +
>> struct iommu_domain domain; /* generic domain data structure for
>> iommu core */
>> };
>> --
>> 2.7.4
>