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.maheshw...@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
