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From: <abhimanyu.saini@xilinx.com>
To: <dev@dpdk.org>
Cc: <chenbo.xia@intel.com>, <maxime.coquelin@redhat.com>,
	<andrew.rybchenko@oktetlabs.ru>, <stable@dpdk.org>,
	Abhimanyu Saini <absaini@amd.com>,
	Vijay Kumar Srivastava <vsrivast@xilinx.com>
Subject: [PATCH v2] vdpa/sfc: handle sync issue between qemu and vhost-user
Date: Tue, 28 Jun 2022 10:59:26 +0530	[thread overview]
Message-ID: <20220628052926.21319-1-asaini@xilinx.com> (raw)
In-Reply-To: <20220627084917.2295-1-asaini@xilinx.com>

From: Abhimanyu Saini <absaini@amd.com>

When DPDK app is running in the VF, it sometimes rings the doorbell
before dev_config has had a chance to complete and hence it misses
the event. As workaround, ring the doorbell when vDPA reports the
notify_area to QEMU.

Fixes: 630be406dcbf ("vdpa/sfc: get queue notify area info")
Cc: stable@dpdk.org

Signed-off-by: Vijay Kumar Srivastava <vsrivast@xilinx.com>
Signed-off-by: Abhimanyu Saini <absaini@amd.com>
---
v1:
* Update the commit id that this patch fixes

 drivers/vdpa/sfc/sfc_vdpa_ops.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/drivers/vdpa/sfc/sfc_vdpa_ops.c b/drivers/vdpa/sfc/sfc_vdpa_ops.c
index b3d9b6c..63aa52d 100644
--- a/drivers/vdpa/sfc/sfc_vdpa_ops.c
+++ b/drivers/vdpa/sfc/sfc_vdpa_ops.c
@@ -794,6 +794,8 @@
 	int vfio_dev_fd;
 	efx_rc_t rc;
 	unsigned int bar_offset;
+	volatile void *doorbell;
+	struct rte_pci_device *pci_dev;
 	struct rte_vdpa_device *vdpa_dev;
 	struct sfc_vdpa_ops_data *ops_data;
 	struct vfio_region_info reg = { .argsz = sizeof(reg) };
@@ -856,6 +858,18 @@
 	sfc_vdpa_info(dev, "vDPA ops get_notify_area :: offset : 0x%" PRIx64,
 		      *offset);
 
+	pci_dev = sfc_vdpa_adapter_by_dev_handle(dev)->pdev;
+	doorbell = (uint8_t *)pci_dev->mem_resource[reg.index].addr + *offset;
+
+	/*
+	 * virtio-net driver in VM sends queue notifications before
+	 * vDPA has a chance to setup the queues and notification area,
+	 * and hence the HW misses these doorbell notifications.
+	 * Since, it is safe to send duplicate doorbell, send another
+	 * doorbell from vDPA driver as workaround for this timing issue.
+	 */
+	rte_write16(qid, doorbell);
+
 	return 0;
 }
 
-- 
1.8.3.1


  parent reply	other threads:[~2022-06-28  5:29 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-06-27  8:49 [PATCH] " abhimanyu.saini
2022-06-27 15:03 ` Andrew Rybchenko
2022-06-28  5:29 ` abhimanyu.saini [this message]
2022-06-28  9:01   ` [PATCH v2] " Andrew Rybchenko
2022-06-30 12:56   ` Maxime Coquelin
2022-07-01 13:58   ` Maxime Coquelin

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