On 2020/10/29 下午3:37, Eli Cohen wrote:
On Thu, Oct 29, 2020 at 03:03:24PM +0800, Jason Wang wrote:
On 2020/10/28 下午10:20, Eli Cohen wrote:
Both irq_bypass_register_producer() and irq_bypass_unregister_producer()
require process context to run. Change the call context lock from
spinlock to mutex to protect the setup process to avoid deadlocks.
Fixes: 265a0ad8731d ("vhost: introduce vhost_vring_call")
Signed-off-by: Eli Cohen <e...@nvidia.com>
Hi Eli:
During review we spot that the spinlock is not necessary. And it was already
protected by vq mutex. So it was removed in this commit:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=86e182fe12ee5869022614457037097c70fe2ed1
Thanks
I see, thanks.
BTW, while testing irq bypassing, I noticed that qemu started crashing
and I fail to boot the VM? Is that a known issue. I checked using
updated master branch of qemu updated yesterday.
Not known yet.
Any ideas how to check this further?
I would be helpful if you can paste the calltrace here.
Did anyone actually check that irq bypassing works?
Yes, Ling Shan tested it via IFCVF driver.
Thanks
---
drivers/vhost/vdpa.c | 10 +++++-----
drivers/vhost/vhost.c | 6 +++---
drivers/vhost/vhost.h | 3 ++-
3 files changed, 10 insertions(+), 9 deletions(-)
diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
index be783592fe58..0a744f2b6e76 100644
--- a/drivers/vhost/vdpa.c
+++ b/drivers/vhost/vdpa.c
@@ -98,26 +98,26 @@ static void vhost_vdpa_setup_vq_irq(struct vhost_vdpa *v,
u16 qid)
return;
irq = ops->get_vq_irq(vdpa, qid);
- spin_lock(&vq->call_ctx.ctx_lock);
+ mutex_lock(&vq->call_ctx.ctx_lock);
irq_bypass_unregister_producer(&vq->call_ctx.producer);
if (!vq->call_ctx.ctx || irq < 0) {
- spin_unlock(&vq->call_ctx.ctx_lock);
+ mutex_unlock(&vq->call_ctx.ctx_lock);
return;
}
vq->call_ctx.producer.token = vq->call_ctx.ctx;
vq->call_ctx.producer.irq = irq;
ret = irq_bypass_register_producer(&vq->call_ctx.producer);
- spin_unlock(&vq->call_ctx.ctx_lock);
+ mutex_unlock(&vq->call_ctx.ctx_lock);
}
static void vhost_vdpa_unsetup_vq_irq(struct vhost_vdpa *v, u16 qid)
{
struct vhost_virtqueue *vq = &v->vqs[qid];
- spin_lock(&vq->call_ctx.ctx_lock);
+ mutex_lock(&vq->call_ctx.ctx_lock);
irq_bypass_unregister_producer(&vq->call_ctx.producer);
- spin_unlock(&vq->call_ctx.ctx_lock);
+ mutex_unlock(&vq->call_ctx.ctx_lock);
}
static void vhost_vdpa_reset(struct vhost_vdpa *v)
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 9ad45e1d27f0..938239e11455 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -302,7 +302,7 @@ static void vhost_vring_call_reset(struct vhost_vring_call
*call_ctx)
{
call_ctx->ctx = NULL;
memset(&call_ctx->producer, 0x0, sizeof(struct irq_bypass_producer));
- spin_lock_init(&call_ctx->ctx_lock);
+ mutex_init(&call_ctx->ctx_lock);
}
static void vhost_vq_reset(struct vhost_dev *dev,
@@ -1650,9 +1650,9 @@ long vhost_vring_ioctl(struct vhost_dev *d, unsigned int
ioctl, void __user *arg
break;
}
- spin_lock(&vq->call_ctx.ctx_lock);
+ mutex_lock(&vq->call_ctx.ctx_lock);
swap(ctx, vq->call_ctx.ctx);
- spin_unlock(&vq->call_ctx.ctx_lock);
+ mutex_unlock(&vq->call_ctx.ctx_lock);
break;
case VHOST_SET_VRING_ERR:
if (copy_from_user(&f, argp, sizeof f)) {
diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h
index 9032d3c2a9f4..e8855ea04205 100644
--- a/drivers/vhost/vhost.h
+++ b/drivers/vhost/vhost.h
@@ -64,7 +64,8 @@ enum vhost_uaddr_type {
struct vhost_vring_call {
struct eventfd_ctx *ctx;
struct irq_bypass_producer producer;
- spinlock_t ctx_lock;
+ /* protect vq irq setup */
+ struct mutex ctx_lock;
};
/* The virtqueue structure describes a queue attached to a device. */
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