在 2021/4/22 下午4:07, Eli Cohen 写道:
On Thu, Apr 22, 2021 at 09:03:58AM +0300, Eli Cohen wrote:
On Thu, Apr 22, 2021 at 10:37:38AM +0800, Jason Wang wrote:
在 2021/4/21 下午6:41, Eli Cohen 写道:
Implement mlx5_get_vq_notification() to return the doorbell address.
Size is set to one system page as required.
Signed-off-by: Eli Cohen <elic@xxxxxxxxxx>
---
drivers/vdpa/mlx5/core/mlx5_vdpa.h | 1 +
drivers/vdpa/mlx5/core/resources.c | 1 +
drivers/vdpa/mlx5/net/mlx5_vnet.c | 6 ++++++
3 files changed, 8 insertions(+)
diff --git a/drivers/vdpa/mlx5/core/mlx5_vdpa.h b/drivers/vdpa/mlx5/core/mlx5_vdpa.h
index b6cc53ba980c..49de62cda598 100644
--- a/drivers/vdpa/mlx5/core/mlx5_vdpa.h
+++ b/drivers/vdpa/mlx5/core/mlx5_vdpa.h
@@ -41,6 +41,7 @@ struct mlx5_vdpa_resources {
u32 pdn;
struct mlx5_uars_page *uar;
void __iomem *kick_addr;
+ u64 phys_kick_addr;
u16 uid;
u32 null_mkey;
bool valid;
diff --git a/drivers/vdpa/mlx5/core/resources.c b/drivers/vdpa/mlx5/core/resources.c
index 6521cbd0f5c2..665f8fc1710f 100644
--- a/drivers/vdpa/mlx5/core/resources.c
+++ b/drivers/vdpa/mlx5/core/resources.c
@@ -247,6 +247,7 @@ int mlx5_vdpa_alloc_resources(struct mlx5_vdpa_dev *mvdev)
goto err_key;
kick_addr = mdev->bar_addr + offset;
+ res->phys_kick_addr = kick_addr;
res->kick_addr = ioremap(kick_addr, PAGE_SIZE);
if (!res->kick_addr) {
diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
index 10c5fef3c020..680751074d2a 100644
--- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
+++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
@@ -1865,8 +1865,14 @@ static void mlx5_vdpa_free(struct vdpa_device *vdev)
static struct vdpa_notification_area mlx5_get_vq_notification(struct vdpa_device *vdev, u16 idx)
{
+ struct mlx5_vdpa_dev *mvdev = to_mvdev(vdev);
struct vdpa_notification_area ret = {};
+ struct mlx5_vdpa_net *ndev;
+
+ ndev = to_mlx5_vdpa_ndev(mvdev);
+ ret.addr = (phys_addr_t)ndev->mvdev.res.phys_kick_addr;
+ ret.size = PAGE_SIZE;
Note that the page will be mapped in to guest, so it's only safe if the
doorbeel exclusively own the page. This means if there're other registers in
the page, we can not let the doorbell bypass to work.
So this is suspicious at least in the case of subfunction where we calculate
the bar length in mlx5_sf_dev_table_create() as:
table->sf_bar_length = 1 << (MLX5_CAP_GEN(dev, log_min_sf_size) + 12);
It looks to me this can only work for the arch with PAGE_SIZE = 4096,
otherwise we can map more into the userspace(guest).
Correct, so I guess I should return here 4096.
I'm not quite sure but since the calculation of the sf_bar_length is
doen via a shift of 12, it might be correct.
And please double check if the doorbell own the page exclusively.
I also think that the check in vhost_vdpa_mmap() should verify that the
returned size is not smaller than PAGE_SIZE because the returned address
Actually I think it's ok since you verify the size equals vma->vm_end -
vma->vm_start which must be at least PAGE_SIZE.
Yes.
Thanks
might just be aligned to PAGE_SIZE. I think this should be enoght but
maybe also use the same logic in vhost_vdpa_fault().
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