Re: [PATCH v3 09/11] iommu: Make iommu_queue_iopf() more generic
From: Baolu Lu
Date: Tue Aug 22 2023 - 04:49:19 EST
On 2023/8/22 1:11, Jason Gunthorpe wrote:
On Fri, Aug 18, 2023 at 07:40:45AM +0800, Lu Baolu wrote:
This completely separates the IO page fault handling framework from the
SVA implementation. Previously, the SVA implementation was tightly coupled
with the IO page fault handling framework. This makes SVA a "customer" of
the IO page fault handling framework by converting domain's page fault
handler to handle a group of faults and calling it directly from
iommu_queue_iopf().
Signed-off-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
---
include/linux/iommu.h | 5 +++--
drivers/iommu/iommu-sva.h | 8 --------
drivers/iommu/io-pgfault.c | 16 +++++++++++++---
drivers/iommu/iommu-sva.c | 14 ++++----------
drivers/iommu/iommu.c | 4 ++--
5 files changed, 22 insertions(+), 25 deletions(-)
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index ff292eea9d31..cf1cb0bb46af 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -41,6 +41,7 @@ struct iommu_sva;
struct iommu_fault_event;
struct iommu_dma_cookie;
struct iopf_queue;
+struct iopf_group;
#define IOMMU_FAULT_PERM_READ (1 << 0) /* read */
#define IOMMU_FAULT_PERM_WRITE (1 << 1) /* write */
@@ -175,8 +176,7 @@ struct iommu_domain {
unsigned long pgsize_bitmap; /* Bitmap of page sizes in use */
struct iommu_domain_geometry geometry;
struct iommu_dma_cookie *iova_cookie;
- enum iommu_page_response_code (*iopf_handler)(struct iommu_fault *fault,
- void *data);
+ int (*iopf_handler)(struct iopf_group *group);
void *fault_data;
union {
struct {
@@ -526,6 +526,7 @@ struct iopf_group {
struct list_head faults;
struct work_struct work;
struct device *dev;
+ void *data;
};
int iommu_device_register(struct iommu_device *iommu,
diff --git a/drivers/iommu/iommu-sva.h b/drivers/iommu/iommu-sva.h
index 510a7df23fba..cf41e88fac17 100644
--- a/drivers/iommu/iommu-sva.h
+++ b/drivers/iommu/iommu-sva.h
@@ -22,8 +22,6 @@ int iopf_queue_flush_dev(struct device *dev);
struct iopf_queue *iopf_queue_alloc(const char *name);
void iopf_queue_free(struct iopf_queue *queue);
int iopf_queue_discard_partial(struct iopf_queue *queue);
-enum iommu_page_response_code
-iommu_sva_handle_iopf(struct iommu_fault *fault, void *data);
void iopf_free_group(struct iopf_group *group);
int iopf_queue_work(struct iopf_group *group, work_func_t func);
int iommu_sva_handle_iopf_group(struct iopf_group *group);
@@ -65,12 +63,6 @@ static inline int iopf_queue_discard_partial(struct iopf_queue *queue)
return -ENODEV;
}
-static inline enum iommu_page_response_code
-iommu_sva_handle_iopf(struct iommu_fault *fault, void *data)
-{
- return IOMMU_PAGE_RESP_INVALID;
-}
-
static inline void iopf_free_group(struct iopf_group *group)
{
}
diff --git a/drivers/iommu/io-pgfault.c b/drivers/iommu/io-pgfault.c
index 00c2e447b740..a61c2aabd1b8 100644
--- a/drivers/iommu/io-pgfault.c
+++ b/drivers/iommu/io-pgfault.c
@@ -11,8 +11,6 @@
#include <linux/slab.h>
#include <linux/workqueue.h>
-#include "iommu-sva.h"
-
/**
* struct iopf_queue - IO Page Fault queue
* @wq: the fault workqueue
@@ -93,6 +91,7 @@ int iommu_queue_iopf(struct iommu_fault *fault, struct device *dev)
{
int ret;
struct iopf_group *group;
+ struct iommu_domain *domain;
struct iopf_fault *iopf, *next;
struct iommu_fault_param *iopf_param;
struct dev_iommu *param = dev->iommu;
@@ -124,6 +123,16 @@ 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);
+
+ if (!domain || !domain->iopf_handler) {
+ ret = -ENODEV;
+ goto cleanup_partial;
+ }
+
group = kzalloc(sizeof(*group), GFP_KERNEL);
if (!group) {
/*
@@ -137,6 +146,7 @@ int iommu_queue_iopf(struct iommu_fault *fault, struct device *dev)
group->dev = dev;
group->last_fault.fault = *fault;
+ group->data = domain->fault_data;
INIT_LIST_HEAD(&group->faults);
list_add(&group->last_fault.list, &group->faults);
@@ -147,7 +157,7 @@ int iommu_queue_iopf(struct iommu_fault *fault, struct device *dev)
list_move(&iopf->list, &group->faults);
}
- ret = iommu_sva_handle_iopf_group(group);
+ ret = domain->iopf_handler(group);
if (ret)
iopf_free_group(group);
diff --git a/drivers/iommu/iommu-sva.c b/drivers/iommu/iommu-sva.c
index df8734b6ec00..2811f34947ab 100644
--- a/drivers/iommu/iommu-sva.c
+++ b/drivers/iommu/iommu-sva.c
@@ -148,13 +148,14 @@ 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;
struct vm_area_struct *vma;
- struct mm_struct *mm = data;
unsigned int access_flags = 0;
+ struct iommu_domain *domain = data;
+ struct mm_struct *mm = domain->mm;
unsigned int fault_flags = FAULT_FLAG_REMOTE;
struct iommu_fault_page_request *prm = &fault->prm;
enum iommu_page_response_code status = IOMMU_PAGE_RESP_INVALID;
@@ -231,23 +232,16 @@ static void iommu_sva_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);
}
iommu_sva_complete_iopf(group->dev, &group->last_fault, status);
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index b280b9f4d8b4..9b622088c741 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -3395,8 +3395,8 @@ 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->fault_data = mm;
+ domain->iopf_handler = iommu_sva_handle_iopf_group;
+ domain->fault_data = domain;
Why fault_data? The domain handling the fault should be passed
through naturally without relying on fault_data.
eg make
iommu_sva_handle_iopf(struct iommu_fault *fault, void *data)
into
iommu_sva_handle_iopf(struct iommu_fault *fault, struct iommu_domain *domain)
See your point now. I will remove "void *data" and move "domain" to
"group->domain".
And delete domain->fault_data until we have some use for it.
Perhaps we will soon have a use for it.
In the iommufd case, the iommufd iopf handler has a need to retrieve the
hwpt pointer from a domain pointer, right? With the domain->fault_data
pointing to the hwpt, the iopf handler has no need to lookup it in the
critical path.
The core code should be keeping track of the iommu_domain lifetime.
I added the debugging code in the next patch as you suggested.
Best regards,
baolu