* [PATCH] vdpa/ifc/base: wait for queue disable before saving q-state
@ 2022-10-25 7:51 Abhishek Maheshwari
2022-10-26 5:32 ` Maxime Coquelin
0 siblings, 1 reply; 3+ messages in thread
From: Abhishek Maheshwari @ 2022-10-25 7:51 UTC (permalink / raw)
To: xiao.w.wang, chenbo.xia; +Cc: abhishek.maheshwari, dev, purna.chandra.mandal
Some ifc hardware require synchronization between disabling a queue and
saving queue-state from LM registers. When queue is disabled from vDPA
driver, ifc device stops executing new virtio-cmds and then updates LM
registers with used/avail index. Before saving the queue-state, vDPA
driver should wait until the queue is disabled from backend.
Signed-off-by: Abhishek Maheshwari <abhishek.maheshwari@intel.com>
---
drivers/vdpa/ifc/base/ifcvf.c | 15 +++++++++++++++
1 file changed, 15 insertions(+)
diff --git a/drivers/vdpa/ifc/base/ifcvf.c b/drivers/vdpa/ifc/base/ifcvf.c
index f1e1474447..76690c1f55 100644
--- a/drivers/vdpa/ifc/base/ifcvf.c
+++ b/drivers/vdpa/ifc/base/ifcvf.c
@@ -257,6 +257,7 @@ ifcvf_hw_disable(struct ifcvf_hw *hw)
u32 i;
struct ifcvf_pci_common_cfg *cfg;
u32 ring_state;
+ int q_disable_tries;
cfg = hw->common_cfg;
if (!cfg) {
@@ -275,6 +276,20 @@ ifcvf_hw_disable(struct ifcvf_hw *hw)
continue;
}
+ /* Some ifc hardware require synchronization between disabling a queue
+ * and saving queue-state from LM registers. When queue is disabled from
+ * vDPA driver, ifc device stops executing new virtio-cmds and then
+ * updates LM registers with used/avail index. Before saving the
+ * queue-state, vDPA driver waits until the queue is disabled from
+ * backend.
+ */
+ q_disable_tries = 10;
+ while (q_disable_tries-- && IFCVF_READ_REG16(&cfg->queue_enable))
+ msec_delay(10);
+
+ if (IFCVF_READ_REG16(&cfg->queue_enable))
+ WARNINGOUT("Failed Q disable: %d. saved state is invalid\n", i);
+
if (hw->device_type == IFCVF_BLK)
ring_state = *(u32 *)(hw->lm_cfg +
IFCVF_LM_RING_STATE_OFFSET +
--
2.31.1
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] vdpa/ifc/base: wait for queue disable before saving q-state
2022-10-25 7:51 [PATCH] vdpa/ifc/base: wait for queue disable before saving q-state Abhishek Maheshwari
@ 2022-10-26 5:32 ` Maxime Coquelin
0 siblings, 0 replies; 3+ messages in thread
From: Maxime Coquelin @ 2022-10-26 5:32 UTC (permalink / raw)
To: Abhishek Maheshwari, xiao.w.wang, chenbo.xia; +Cc: dev, purna.chandra.mandal
Hi Abhishek,
On 10/25/22 09:51, Abhishek Maheshwari wrote:
> Some ifc hardware require synchronization between disabling a queue and
> saving queue-state from LM registers. When queue is disabled from vDPA
> driver, ifc device stops executing new virtio-cmds and then updates LM
> registers with used/avail index. Before saving the queue-state, vDPA
> driver should wait until the queue is disabled from backend.
I think it should be considered a fix, and so requires a Fixes tag and
stable@dpdk.org to be cc'ed.
> Signed-off-by: Abhishek Maheshwari <abhishek.maheshwari@intel.com>
> ---
> drivers/vdpa/ifc/base/ifcvf.c | 15 +++++++++++++++
> 1 file changed, 15 insertions(+)
>
> diff --git a/drivers/vdpa/ifc/base/ifcvf.c b/drivers/vdpa/ifc/base/ifcvf.c
> index f1e1474447..76690c1f55 100644
> --- a/drivers/vdpa/ifc/base/ifcvf.c
> +++ b/drivers/vdpa/ifc/base/ifcvf.c
> @@ -257,6 +257,7 @@ ifcvf_hw_disable(struct ifcvf_hw *hw)
> u32 i;
> struct ifcvf_pci_common_cfg *cfg;
> u32 ring_state;
> + int q_disable_tries;
>
> cfg = hw->common_cfg;
> if (!cfg) {
> @@ -275,6 +276,20 @@ ifcvf_hw_disable(struct ifcvf_hw *hw)
> continue;
> }
>
> + /* Some ifc hardware require synchronization between disabling a queue
> + * and saving queue-state from LM registers. When queue is disabled from
> + * vDPA driver, ifc device stops executing new virtio-cmds and then
> + * updates LM registers with used/avail index. Before saving the
> + * queue-state, vDPA driver waits until the queue is disabled from
> + * backend.
> + */
> + q_disable_tries = 10;
> + while (q_disable_tries-- && IFCVF_READ_REG16(&cfg->queue_enable))
> + msec_delay(10);
> +
> + if (IFCVF_READ_REG16(&cfg->queue_enable))
> + WARNINGOUT("Failed Q disable: %d. saved state is invalid\n", i);
Maybe checking q_disable_tries > 0 is enough here.
Also, should we really continue the disablement if synchronization
failed?
> +
> if (hw->device_type == IFCVF_BLK)
> ring_state = *(u32 *)(hw->lm_cfg +
> IFCVF_LM_RING_STATE_OFFSET +
^ permalink raw reply [flat|nested] 3+ messages in thread
* [PATCH] vdpa/ifc/base: wait for queue disable before saving q-state
@ 2022-10-25 7:23 Abhishek Maheshwari
0 siblings, 0 replies; 3+ messages in thread
From: Abhishek Maheshwari @ 2022-10-25 7:23 UTC (permalink / raw)
To: abhishek.maheshwari; +Cc: dev, chenbo.xia, purna.chandra.mandal
Some ifc hardware require synchronization between disabling a queue and
saving queue-state from LM registers. When queue is disabled from vDPA
driver, ifc device stops executing new virtio-cmds and then updates LM
registers with used/avail index. Before saving the queue-state, vDPA
driver should wait until the queue is disabled from backend.
Signed-off-by: Abhishek Maheshwari <abhishek.maheshwari@intel.com>
---
drivers/vdpa/ifc/base/ifcvf.c | 15 +++++++++++++++
1 file changed, 15 insertions(+)
diff --git a/drivers/vdpa/ifc/base/ifcvf.c b/drivers/vdpa/ifc/base/ifcvf.c
index f1e1474447..fb51c793a2 100644
--- a/drivers/vdpa/ifc/base/ifcvf.c
+++ b/drivers/vdpa/ifc/base/ifcvf.c
@@ -257,6 +257,7 @@ ifcvf_hw_disable(struct ifcvf_hw *hw)
u32 i;
struct ifcvf_pci_common_cfg *cfg;
u32 ring_state;
+ int q_disable_tries;
cfg = hw->common_cfg;
if (!cfg) {
@@ -275,6 +276,20 @@ ifcvf_hw_disable(struct ifcvf_hw *hw)
continue;
}
+ /* Some ifc hardware require synchronization between disabling a queue
+ * and saving queue-state from LM registers.
+ * When queue is disabled from vDPA driver, ifc device stops executing
+ * new virtio-cmds and then updates LM registers with used/avail index.
+ * Before saving the queue-state, vDPA driver waits until the queue is
+ * disabled from backend.
+ */
+ q_disable_tries = 10;
+ while (q_disable_tries-- && IFCVF_READ_REG16(&cfg->queue_enable))
+ msec_delay(10);
+
+ if (IFCVF_READ_REG16(&cfg->queue_enable))
+ WARNINGOUT("Failed Q disable: %d. saved state is invalid\n", i);
+
if (hw->device_type == IFCVF_BLK)
ring_state = *(u32 *)(hw->lm_cfg +
IFCVF_LM_RING_STATE_OFFSET +
--
2.31.1
^ permalink raw reply [flat|nested] 3+ messages in thread
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2022-10-25 7:51 [PATCH] vdpa/ifc/base: wait for queue disable before saving q-state Abhishek Maheshwari
2022-10-26 5:32 ` Maxime Coquelin
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