Re: [PATCH v2 2/3] virito_pci: add timeout to reset device operation
在 2021/4/8 下午8:57, Max Gurtovoy 写道: On 4/8/2021 3:45 PM, Jason Wang wrote: 在 2021/4/8 下午5:44, Max Gurtovoy 写道: On 4/8/2021 12:01 PM, Jason Wang wrote: 在 2021/4/8 下午4:11, Max Gurtovoy 写道: According to the spec after writing 0 to device_status, the driver MUST wait for a read of device_status to return 0 before reinitializing the device. In case we have a device that won't return 0, the reset operation will loop forever and cause the host/vm to stuck. Set timeout for 3 minutes before giving up on the device. Signed-off-by: Max Gurtovoy --- drivers/virtio/virtio_pci_modern.c | 10 +- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/drivers/virtio/virtio_pci_modern.c b/drivers/virtio/virtio_pci_modern.c index cc3412a96a17..dcee616e8d21 100644 --- a/drivers/virtio/virtio_pci_modern.c +++ b/drivers/virtio/virtio_pci_modern.c @@ -162,6 +162,7 @@ static int vp_reset(struct virtio_device *vdev) { struct virtio_pci_device *vp_dev = to_vp_device(vdev); struct virtio_pci_modern_device *mdev = &vp_dev->mdev; + unsigned long timeout = jiffies + msecs_to_jiffies(18); /* 0 status means a reset. */ vp_modern_set_status(mdev, 0); @@ -169,9 +170,16 @@ static int vp_reset(struct virtio_device *vdev) * device_status to return 0 before reinitializing the device. * This will flush out the status write, and flush in device writes, * including MSI-X interrupts, if any. + * Set a timeout before giving up on the device. */ - while (vp_modern_get_status(mdev)) + while (vp_modern_get_status(mdev)) { + if (time_after(jiffies, timeout)) { What happens if the device finish the rest after the timeout? The driver will set VIRTIO_CONFIG_S_FAILED and one can re-probe it later on (e.g by re-scanning the pci bus). Ok, so do we need the flush through vp_synchronize_vectors() here? If the device didn't write 0 to status I guess we don't need that. The device shouldn't raise any interrupt before negotiation finish successfully. The reset could be triggered in other places like driver removing. Thanks MST, is that correct ? Thanks Thanks + dev_err(&vdev->dev, "virtio: device not ready. " + "Aborting. Try again later\n"); + return -EAGAIN; + } msleep(1); + } /* Flush pending VQ/configuration callbacks. */ vp_synchronize_vectors(vdev); return 0; ___ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization
Re: [PATCH v2 2/3] virito_pci: add timeout to reset device operation
在 2021/4/8 下午5:44, Max Gurtovoy 写道: On 4/8/2021 12:01 PM, Jason Wang wrote: 在 2021/4/8 下午4:11, Max Gurtovoy 写道: According to the spec after writing 0 to device_status, the driver MUST wait for a read of device_status to return 0 before reinitializing the device. In case we have a device that won't return 0, the reset operation will loop forever and cause the host/vm to stuck. Set timeout for 3 minutes before giving up on the device. Signed-off-by: Max Gurtovoy --- drivers/virtio/virtio_pci_modern.c | 10 +- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/drivers/virtio/virtio_pci_modern.c b/drivers/virtio/virtio_pci_modern.c index cc3412a96a17..dcee616e8d21 100644 --- a/drivers/virtio/virtio_pci_modern.c +++ b/drivers/virtio/virtio_pci_modern.c @@ -162,6 +162,7 @@ static int vp_reset(struct virtio_device *vdev) { struct virtio_pci_device *vp_dev = to_vp_device(vdev); struct virtio_pci_modern_device *mdev = &vp_dev->mdev; + unsigned long timeout = jiffies + msecs_to_jiffies(18); /* 0 status means a reset. */ vp_modern_set_status(mdev, 0); @@ -169,9 +170,16 @@ static int vp_reset(struct virtio_device *vdev) * device_status to return 0 before reinitializing the device. * This will flush out the status write, and flush in device writes, * including MSI-X interrupts, if any. + * Set a timeout before giving up on the device. */ - while (vp_modern_get_status(mdev)) + while (vp_modern_get_status(mdev)) { + if (time_after(jiffies, timeout)) { What happens if the device finish the rest after the timeout? The driver will set VIRTIO_CONFIG_S_FAILED and one can re-probe it later on (e.g by re-scanning the pci bus). Ok, so do we need the flush through vp_synchronize_vectors() here? Thanks Thanks + dev_err(&vdev->dev, "virtio: device not ready. " + "Aborting. Try again later\n"); + return -EAGAIN; + } msleep(1); + } /* Flush pending VQ/configuration callbacks. */ vp_synchronize_vectors(vdev); return 0; ___ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization
Re: [PATCH v2 2/3] virito_pci: add timeout to reset device operation
在 2021/4/8 下午4:11, Max Gurtovoy 写道: According to the spec after writing 0 to device_status, the driver MUST wait for a read of device_status to return 0 before reinitializing the device. In case we have a device that won't return 0, the reset operation will loop forever and cause the host/vm to stuck. Set timeout for 3 minutes before giving up on the device. Signed-off-by: Max Gurtovoy --- drivers/virtio/virtio_pci_modern.c | 10 +- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/drivers/virtio/virtio_pci_modern.c b/drivers/virtio/virtio_pci_modern.c index cc3412a96a17..dcee616e8d21 100644 --- a/drivers/virtio/virtio_pci_modern.c +++ b/drivers/virtio/virtio_pci_modern.c @@ -162,6 +162,7 @@ static int vp_reset(struct virtio_device *vdev) { struct virtio_pci_device *vp_dev = to_vp_device(vdev); struct virtio_pci_modern_device *mdev = &vp_dev->mdev; + unsigned long timeout = jiffies + msecs_to_jiffies(18); /* 0 status means a reset. */ vp_modern_set_status(mdev, 0); @@ -169,9 +170,16 @@ static int vp_reset(struct virtio_device *vdev) * device_status to return 0 before reinitializing the device. * This will flush out the status write, and flush in device writes, * including MSI-X interrupts, if any. +* Set a timeout before giving up on the device. */ - while (vp_modern_get_status(mdev)) + while (vp_modern_get_status(mdev)) { + if (time_after(jiffies, timeout)) { What happens if the device finish the rest after the timeout? Thanks + dev_err(&vdev->dev, "virtio: device not ready. " + "Aborting. Try again later\n"); + return -EAGAIN; + } msleep(1); + } /* Flush pending VQ/configuration callbacks. */ vp_synchronize_vectors(vdev); return 0; ___ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization