On 2023/8/11 3:07, Jason Gunthorpe wrote:
On Thu, Jul 27, 2023 at 01:48:35PM +0800, Lu Baolu wrote:
@@ -137,6 +136,16 @@ int iommu_queue_iopf(struct iommu_fault *fault, struct device *dev)
return 0;
}
+ if (fault->prm.flags & IOMMU_FAULT_PAGE_REQUEST_PASID_VALID)
+ domain = iommu_get_domain_for_dev_pasid(dev, fault->prm.pasid, 0);
+ else
+ domain = iommu_get_domain_for_dev(dev);
How does the lifetime work for this? What prevents UAF on domain?
Replied below.
diff --git a/drivers/iommu/iommu-sva.c b/drivers/iommu/iommu-sva.c
index ab42cfdd7636..668f4c2bcf65 100644
--- a/drivers/iommu/iommu-sva.c
+++ b/drivers/iommu/iommu-sva.c
@@ -157,7 +157,7 @@ EXPORT_SYMBOL_GPL(iommu_sva_get_pasid);
/*
* I/O page fault handler for SVA
*/
-enum iommu_page_response_code
+static enum iommu_page_response_code
iommu_sva_handle_iopf(struct iommu_fault *fault, void *data)
{
vm_fault_t ret;
@@ -241,23 +241,16 @@ static void iopf_handler(struct work_struct *work)
{
struct iopf_fault *iopf;
struct iopf_group *group;
- struct iommu_domain *domain;
enum iommu_page_response_code status = IOMMU_PAGE_RESP_SUCCESS;
group = container_of(work, struct iopf_group, work);
- domain = iommu_get_domain_for_dev_pasid(group->dev,
- group->last_fault.fault.prm.pasid, 0);
- if (!domain || !domain->iopf_handler)
- status = IOMMU_PAGE_RESP_INVALID;
-
list_for_each_entry(iopf, &group->faults, list) {
/*
* For the moment, errors are sticky: don't handle subsequent
* faults in the group if there is an error.
*/
if (status == IOMMU_PAGE_RESP_SUCCESS)
- status = domain->iopf_handler(&iopf->fault,
- domain->fault_data);
+ status = iommu_sva_handle_iopf(&iopf->fault, group->data);
}
iopf_complete_group(group->dev, &group->last_fault, status);
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 157a28a49473..535a36e3edc9 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -3330,7 +3330,7 @@ struct iommu_domain *iommu_sva_domain_alloc(struct device *dev,
domain->type = IOMMU_DOMAIN_SVA;
mmgrab(mm);
domain->mm = mm;
- domain->iopf_handler = iommu_sva_handle_iopf;
+ domain->iopf_handler = iommu_sva_handle_iopf_group;
domain->fault_data = mm;
This also has lifetime problems on the mm.
The domain should flow into the iommu_sva_handle_iopf() instead of the
void *data.
Okay, but I still want to keep void *data as a private pointer of the
iopf consumer. For SVA, it's probably NULL.
The SVA code can then just use domain->mm directly.
Yes.
We need to document/figure out some how to ensure that the faults are
all done processing before a fault enabled domain can be freed.
This has been documented in drivers/iommu/io-pgfault.c:
[...]
* Any valid page fault will be eventually routed to an iommu domain
and the
* page fault handler installed there will get called. The users of this
* handling framework should guarantee that the iommu domain could only be
* freed after the device has stopped generating page faults (or the iommu
* hardware has been set to block the page faults) and the pending page
faults
* have been flushed.
*
* Return: 0 on success and <0 on error.
*/
int iommu_queue_iopf(struct iommu_fault *fault, void *cookie)
[...]
This patch would be better ordered before the prior patch.
Let me try this in the next version.
Best regards,
baolu
