Tweak the I/O page fault handling framework to route the page faults to
the domain and call the page fault handler retrieved from the domain.
This makes the I/O page fault handling framework possible to serve more
usage scenarios as long as they have an IOMMU domain and install a page
fault handler in it. Some unused functions are also removed to avoid
dead code.
Signed-off-by: Lu Baolu <[email protected]>
---
drivers/iommu/iommu-sva-lib.h | 1 -
drivers/iommu/io-pgfault.c | 69 ++++++-----------------------------
drivers/iommu/iommu-sva-lib.c | 20 ----------
3 files changed, 12 insertions(+), 78 deletions(-)
diff --git a/drivers/iommu/iommu-sva-lib.h b/drivers/iommu/iommu-sva-lib.h
index 0f33472e5212..90d4bd3a61b1 100644
--- a/drivers/iommu/iommu-sva-lib.h
+++ b/drivers/iommu/iommu-sva-lib.h
@@ -8,7 +8,6 @@
#include <linux/ioasid.h>
#include <linux/mm_types.h>
-struct mm_struct *iommu_sva_find(ioasid_t pasid);
struct mm_struct *iommu_sva_domain_mm(struct iommu_domain *domain);
/* I/O Page fault */
diff --git a/drivers/iommu/io-pgfault.c b/drivers/iommu/io-pgfault.c
index 1df8c1dcae77..fc1b2bdeedf8 100644
--- a/drivers/iommu/io-pgfault.c
+++ b/drivers/iommu/io-pgfault.c
@@ -69,62 +69,6 @@ static int iopf_complete_group(struct device *dev, struct iopf_fault *iopf,
return iommu_page_response(dev, &resp);
}
-static enum iommu_page_response_code
-iopf_handle_single(struct iopf_fault *iopf)
-{
- vm_fault_t ret;
- struct mm_struct *mm;
- struct vm_area_struct *vma;
- unsigned int access_flags = 0;
- unsigned int fault_flags = FAULT_FLAG_REMOTE;
- struct iommu_fault_page_request *prm = &iopf->fault.prm;
- enum iommu_page_response_code status = IOMMU_PAGE_RESP_INVALID;
-
- if (!(prm->flags & IOMMU_FAULT_PAGE_REQUEST_PASID_VALID))
- return status;
-
- mm = iommu_sva_find(prm->pasid);
- if (IS_ERR_OR_NULL(mm))
- return status;
-
- mmap_read_lock(mm);
-
- vma = find_extend_vma(mm, prm->addr);
- if (!vma)
- /* Unmapped area */
- goto out_put_mm;
-
- if (prm->perm & IOMMU_FAULT_PERM_READ)
- access_flags |= VM_READ;
-
- if (prm->perm & IOMMU_FAULT_PERM_WRITE) {
- access_flags |= VM_WRITE;
- fault_flags |= FAULT_FLAG_WRITE;
- }
-
- if (prm->perm & IOMMU_FAULT_PERM_EXEC) {
- access_flags |= VM_EXEC;
- fault_flags |= FAULT_FLAG_INSTRUCTION;
- }
-
- if (!(prm->perm & IOMMU_FAULT_PERM_PRIV))
- fault_flags |= FAULT_FLAG_USER;
-
- if (access_flags & ~vma->vm_flags)
- /* Access fault */
- goto out_put_mm;
-
- ret = handle_mm_fault(vma, prm->addr, fault_flags, NULL);
- status = ret & VM_FAULT_ERROR ? IOMMU_PAGE_RESP_INVALID :
- IOMMU_PAGE_RESP_SUCCESS;
-
-out_put_mm:
- mmap_read_unlock(mm);
- mmput(mm);
-
- return status;
-}
-
static void iopf_handle_group(struct work_struct *work)
{
struct iopf_group *group;
@@ -134,12 +78,23 @@ static void iopf_handle_group(struct work_struct *work)
group = container_of(work, struct iopf_group, work);
list_for_each_entry_safe(iopf, next, &group->faults, list) {
+ struct iommu_domain *domain;
+
+ domain = iommu_get_domain_for_dev_pasid_async(group->dev,
+ iopf->fault.prm.pasid);
+ if (!domain || !domain->iopf_handler)
+ status = IOMMU_PAGE_RESP_INVALID;
+
/*
* 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 = iopf_handle_single(iopf);
+ status = domain->iopf_handler(&iopf->fault,
+ domain->fault_data);
+
+ if (domain)
+ iommu_domain_put_async(domain);
if (!(iopf->fault.prm.flags &
IOMMU_FAULT_PAGE_REQUEST_LAST_PAGE))
diff --git a/drivers/iommu/iommu-sva-lib.c b/drivers/iommu/iommu-sva-lib.c
index 1024c61519dc..d84cffaeb331 100644
--- a/drivers/iommu/iommu-sva-lib.c
+++ b/drivers/iommu/iommu-sva-lib.c
@@ -69,26 +69,6 @@ static int iommu_sva_alloc_pasid(struct mm_struct *mm,
return ret;
}
-/* ioasid_find getter() requires a void * argument */
-static bool __mmget_not_zero(void *mm)
-{
- return mmget_not_zero(mm);
-}
-
-/**
- * iommu_sva_find() - Find mm associated to the given PASID
- * @pasid: Process Address Space ID assigned to the mm
- *
- * On success a reference to the mm is taken, and must be released with mmput().
- *
- * Returns the mm corresponding to this PASID, or an error if not found.
- */
-struct mm_struct *iommu_sva_find(ioasid_t pasid)
-{
- return ioasid_find(&iommu_sva_pasid, pasid, __mmget_not_zero);
-}
-EXPORT_SYMBOL_GPL(iommu_sva_find);
-
/*
* Get or put an ioas for a shared memory.
*/
--
2.25.1
On Thu, Apr 21, 2022 at 01:21:20PM +0800, Lu Baolu wrote:
> static void iopf_handle_group(struct work_struct *work)
> {
> struct iopf_group *group;
> @@ -134,12 +78,23 @@ static void iopf_handle_group(struct work_struct *work)
> group = container_of(work, struct iopf_group, work);
>
> list_for_each_entry_safe(iopf, next, &group->faults, list) {
> + struct iommu_domain *domain;
> +
> + domain = iommu_get_domain_for_dev_pasid_async(group->dev,
> + iopf->fault.prm.pasid);
Reading the PCIe spec again (v6.0 10.4.1.1 PASID Usage), all faults within
the group have the same PASID so we could move the domain fetch out of the
loop. It does deviate from the old behavior, though, so we could change
it later.
Thanks,
Jean
> + if (!domain || !domain->iopf_handler)
> + status = IOMMU_PAGE_RESP_INVALID;
> +
> /*
> * 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 = iopf_handle_single(iopf);
> + status = domain->iopf_handler(&iopf->fault,
> + domain->fault_data);
> +
> + if (domain)
> + iommu_domain_put_async(domain);
>
> if (!(iopf->fault.prm.flags &
> IOMMU_FAULT_PAGE_REQUEST_LAST_PAGE))
On 2022/4/28 22:57, Jean-Philippe Brucker wrote:
> On Thu, Apr 21, 2022 at 01:21:20PM +0800, Lu Baolu wrote:
>> static void iopf_handle_group(struct work_struct *work)
>> {
>> struct iopf_group *group;
>> @@ -134,12 +78,23 @@ static void iopf_handle_group(struct work_struct *work)
>> group = container_of(work, struct iopf_group, work);
>>
>> list_for_each_entry_safe(iopf, next, &group->faults, list) {
>> + struct iommu_domain *domain;
>> +
>> + domain = iommu_get_domain_for_dev_pasid_async(group->dev,
>> + iopf->fault.prm.pasid);
> Reading the PCIe spec again (v6.0 10.4.1.1 PASID Usage), all faults within
> the group have the same PASID so we could move the domain fetch out of the
> loop. It does deviate from the old behavior, though, so we could change
> it later.
Perhaps we can add a pasid member in the struct iopf_group and do a
sanity check when a new iopf is added to the group? Here, we just fetch
the domain with group->pasid.
Best regards,
baolu