On Tue, Mar 14, 2023 at 01:36:13PM +0800, Jason Wang wrote:
On Thu, Mar 2, 2023 at 7:35 PM Stefano Garzarella <sgarzare@xxxxxxxxxx> wrote:
The new "use_va" module parameter (default: false) is used in
vdpa_alloc_device() to inform the vDPA framework that the device
supports VA.
vringh is initialized to use VA only when "use_va" is true and the
user's mm has been bound. So, only when the bus supports user VA
(e.g. vhost-vdpa).
vdpasim_mm_work_fn work is used to attach the kthread to the user
address space when the .bind_mm callback is invoked, and to detach
it when the .unbind_mm callback is invoked.
Signed-off-by: Stefano Garzarella <sgarzare@xxxxxxxxxx>
---
Notes:
v2:
- `use_va` set to true by default [Eugenio]
- supported the new unbind_mm callback [Jason]
- removed the unbind_mm call in vdpasim_do_reset() [Jason]
- avoided to release the lock while call kthread_flush_work() since we
are now using a mutex to protect the device state
drivers/vdpa/vdpa_sim/vdpa_sim.h | 1 +
drivers/vdpa/vdpa_sim/vdpa_sim.c | 98 +++++++++++++++++++++++++++++++-
2 files changed, 97 insertions(+), 2 deletions(-)
diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.h b/drivers/vdpa/vdpa_sim/vdpa_sim.h
index 4774292fba8c..3a42887d05d9 100644
--- a/drivers/vdpa/vdpa_sim/vdpa_sim.h
+++ b/drivers/vdpa/vdpa_sim/vdpa_sim.h
@@ -59,6 +59,7 @@ struct vdpasim {
struct vdpasim_virtqueue *vqs;
struct kthread_worker *worker;
struct kthread_work work;
+ struct mm_struct *mm_bound;
struct vdpasim_dev_attr dev_attr;
/* mutex to synchronize virtqueue state */
struct mutex mutex;
diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.c b/drivers/vdpa/vdpa_sim/vdpa_sim.c
index a28103a67ae7..eda26bc33df5 100644
--- a/drivers/vdpa/vdpa_sim/vdpa_sim.c
+++ b/drivers/vdpa/vdpa_sim/vdpa_sim.c
@@ -35,10 +35,77 @@ module_param(max_iotlb_entries, int, 0444);
MODULE_PARM_DESC(max_iotlb_entries,
"Maximum number of iotlb entries for each address space. 0 means unlimited. (default: 2048)");
+static bool use_va = true;
+module_param(use_va, bool, 0444);
+MODULE_PARM_DESC(use_va, "Enable/disable the device's ability to use VA");
+
#define VDPASIM_QUEUE_ALIGN PAGE_SIZE
#define VDPASIM_QUEUE_MAX 256
#define VDPASIM_VENDOR_ID 0
+struct vdpasim_mm_work {
+ struct kthread_work work;
+ struct mm_struct *mm;
+ bool bind;
+ int ret;
+};
+
+static void vdpasim_mm_work_fn(struct kthread_work *work)
+{
+ struct vdpasim_mm_work *mm_work =
+ container_of(work, struct vdpasim_mm_work, work);
+
+ mm_work->ret = 0;
+
+ if (mm_work->bind) {
+ kthread_use_mm(mm_work->mm);
+ //TODO: should we attach the cgroup of the mm owner?
+ } else {
+ kthread_unuse_mm(mm_work->mm);
+ }
+}
+
+static void vdpasim_worker_queue_mm(struct vdpasim *vdpasim,
+ struct vdpasim_mm_work *mm_work)
+{
Nit: we need to tweak the name as it does flush besides queuing the work.
Yep, or split in 2 functions.
+ struct kthread_work *work = &mm_work->work;
+
+ kthread_init_work(work, vdpasim_mm_work_fn);
+ kthread_queue_work(vdpasim->worker, work);
+
+ kthread_flush_work(work);
+}
+
+static int vdpasim_worker_bind_mm(struct vdpasim *vdpasim,
+ struct mm_struct *new_mm)
+{
+ struct vdpasim_mm_work mm_work;
+
+ mm_work.mm = new_mm;
+ mm_work.bind = true;
+
+ vdpasim_worker_queue_mm(vdpasim, &mm_work);
+
+ if (!mm_work.ret)
+ vdpasim->mm_bound = new_mm;
+
+ return mm_work.ret;
+}
+
+static void vdpasim_worker_unbind_mm(struct vdpasim *vdpasim)
+{
+ struct vdpasim_mm_work mm_work;
+
+ if (!vdpasim->mm_bound)
+ return;
+
+ mm_work.mm = vdpasim->mm_bound;
+ mm_work.bind = false;
Can we simply use mm_work.mm = NULL for unbinding?
+
+ vdpasim_worker_queue_mm(vdpasim, &mm_work);
+
+ vdpasim->mm_bound = NULL;
And change the mm_bound in the worker?
Yep, I need to put `vdpasim` in struct vdpasim_mm_work.
I'll do in the next version.
Thanks,
Stefano
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