On 2020/5/11 下午6:11, Zhu, Lingshan wrote:
On 5/11/2020 5:26 PM, Jason Wang wrote:On 2020/5/11 下午3:19, Zhu Lingshan wrote:This commit move IRQ request and free operations from probe() to VIRTIO status change handler to comply with VIRTIO spec. VIRTIO spec 1.1, section 2.1.2 Device Requirements: Device Status Field The device MUST NOT consume buffers or send any used buffer notifications to the driver before DRIVER_OK.My previous explanation might be wrong here. It depends on how you implement your hardware, if you hardware guarantee that no interrupt will be triggered before DRIVER_OK, then it's fine.And the main goal for this patch is to allocate the interrupt on demand.Hi Jason, So these code can a double assurance.Signed-off-by: Zhu Lingshan <lingshan.zhu@xxxxxxxxx> ---drivers/vdpa/ifcvf/ifcvf_main.c | 119 ++++++++++++++++++++++++----------------1 file changed, 73 insertions(+), 46 deletions(-)diff --git a/drivers/vdpa/ifcvf/ifcvf_main.c b/drivers/vdpa/ifcvf/ifcvf_main.cindex abf6a061..4d58bf2 100644 --- a/drivers/vdpa/ifcvf/ifcvf_main.c +++ b/drivers/vdpa/ifcvf/ifcvf_main.c@@ -28,6 +28,60 @@ static irqreturn_t ifcvf_intr_handler(int irq, void *arg)return IRQ_HANDLED; } +static void ifcvf_free_irq_vectors(void *data) +{ + pci_free_irq_vectors(data); +} + +static void ifcvf_free_irq(struct ifcvf_adapter *adapter, int queues) +{ + struct pci_dev *pdev = adapter->pdev; + struct ifcvf_hw *vf = &adapter->vf; + int i; + + + for (i = 0; i < queues; i++) + devm_free_irq(&pdev->dev, vf->vring[i].irq, &vf->vring[i]); + + ifcvf_free_irq_vectors(pdev); +} + +static int ifcvf_request_irq(struct ifcvf_adapter *adapter) +{ + struct pci_dev *pdev = adapter->pdev; + struct ifcvf_hw *vf = &adapter->vf; + int vector, i, ret, irq; + + ret = pci_alloc_irq_vectors(pdev, IFCVF_MAX_INTR, + IFCVF_MAX_INTR, PCI_IRQ_MSIX); + if (ret < 0) { + IFCVF_ERR(pdev, "Failed to alloc IRQ vectors\n"); + return ret; + } + + for (i = 0; i < IFCVF_MAX_QUEUE_PAIRS * 2; i++) { + snprintf(vf->vring[i].msix_name, 256, "ifcvf[%s]-%d\n", + pci_name(pdev), i); + vector = i + IFCVF_MSI_QUEUE_OFF; + irq = pci_irq_vector(pdev, vector); + ret = devm_request_irq(&pdev->dev, irq, + ifcvf_intr_handler, 0, + vf->vring[i].msix_name, + &vf->vring[i]); + if (ret) { + IFCVF_ERR(pdev, + "Failed to request irq for vq %d\n", i); + ifcvf_free_irq(adapter, i);I'm not sure this unwind is correct. It looks like we should loop and call devm_free_irq() for virtqueue [0, i);we have the loop in ifcvf_free_irq(struct ifcvf_adapter *adapter, int queues), it takes a parameter queues, and a loop+ for (i = 0; i < queues; i++)+ devm_free_irq(&pdev->dev, vf->vring[i].irq, &vf->vring[i]); will free irq for vq[0,queues)
Aha, I get this.
+ + return ret; + } + + vf->vring[i].irq = irq; + } + + return 0; +} + static int ifcvf_start_datapath(void *private) { struct ifcvf_hw *vf = ifcvf_private_to_vf(private);@@ -118,9 +172,12 @@ static void ifcvf_vdpa_set_status(struct vdpa_device *vdpa_dev, u8 status){ struct ifcvf_adapter *adapter; struct ifcvf_hw *vf; + u8 status_old; + int ret; vf = vdpa_to_vf(vdpa_dev); adapter = dev_get_drvdata(vdpa_dev->dev.parent); + status_old = ifcvf_get_status(vf); if (status == 0) { ifcvf_stop_datapath(adapter);@@ -128,7 +185,22 @@ static void ifcvf_vdpa_set_status(struct vdpa_device *vdpa_dev, u8 status)return; } - if (status & VIRTIO_CONFIG_S_DRIVER_OK) { + if ((status_old & VIRTIO_CONFIG_S_DRIVER_OK) && + !(status & VIRTIO_CONFIG_S_DRIVER_OK)) { + ifcvf_stop_datapath(adapter); + ifcvf_free_irq(adapter, IFCVF_MAX_QUEUE_PAIRS * 2); + } + + if ((status & VIRTIO_CONFIG_S_DRIVER_OK) && + !(status_old & VIRTIO_CONFIG_S_DRIVER_OK)) { + ret = ifcvf_request_irq(adapter); + if (ret) { + status = ifcvf_get_status(vf); + status |= VIRTIO_CONFIG_S_FAILED; + ifcvf_set_status(vf, status); + return; + } +Have a hard though on the logic here.This depends on the status setting from guest or userspace. Which means it can not deal with e.g when qemu or userspace is crashed? Do we need to care this or it's a over engineering?ThanksIf qemu crash, I guess users may re-run qmeu / re-initialize the device, according to the spec, there should be a reset routine. This code piece handles status change on DRIVER_OK flipping. I am not sure I get your point, mind to give more hints?
The problem is if we don't launch new qemu instance, the interrupt will be still there?
Thanks
Thanks, BR Zhu Lingshanif (ifcvf_start_datapath(adapter) < 0) IFCVF_ERR(adapter->pdev, "Failed to set ifcvf vdpa status %u\n",@@ -284,38 +356,6 @@ static void ifcvf_vdpa_set_config_cb(struct vdpa_device *vdpa_dev,.set_config_cb = ifcvf_vdpa_set_config_cb, }; -static int ifcvf_request_irq(struct ifcvf_adapter *adapter) -{ - struct pci_dev *pdev = adapter->pdev; - struct ifcvf_hw *vf = &adapter->vf; - int vector, i, ret, irq; - - - for (i = 0; i < IFCVF_MAX_QUEUE_PAIRS * 2; i++) { - snprintf(vf->vring[i].msix_name, 256, "ifcvf[%s]-%d\n", - pci_name(pdev), i); - vector = i + IFCVF_MSI_QUEUE_OFF; - irq = pci_irq_vector(pdev, vector); - ret = devm_request_irq(&pdev->dev, irq, - ifcvf_intr_handler, 0, - vf->vring[i].msix_name, - &vf->vring[i]); - if (ret) { - IFCVF_ERR(pdev, - "Failed to request irq for vq %d\n", i); - return ret; - } - vf->vring[i].irq = irq; - } - - return 0; -} - -static void ifcvf_free_irq_vectors(void *data) -{ - pci_free_irq_vectors(data); -} -static int ifcvf_probe(struct pci_dev *pdev, const struct pci_device_id *id){ struct device *dev = &pdev->dev;@@ -349,13 +389,6 @@ static int ifcvf_probe(struct pci_dev *pdev, const struct pci_device_id *id)return ret; } - ret = pci_alloc_irq_vectors(pdev, IFCVF_MAX_INTR, - IFCVF_MAX_INTR, PCI_IRQ_MSIX); - if (ret < 0) { - IFCVF_ERR(pdev, "Failed to alloc irq vectors\n"); - return ret; - } -ret = devm_add_action_or_reset(dev, ifcvf_free_irq_vectors, pdev);if (ret) { IFCVF_ERR(pdev,@@ -379,12 +412,6 @@ static int ifcvf_probe(struct pci_dev *pdev, const struct pci_device_id *id)adapter->pdev = pdev; adapter->vdpa.dma_dev = &pdev->dev; - ret = ifcvf_request_irq(adapter); - if (ret) { - IFCVF_ERR(pdev, "Failed to request MSI-X irq\n"); - goto err; - } - ret = ifcvf_init_hw(vf, pdev); if (ret) { IFCVF_ERR(pdev, "Failed to init IFCVF hw\n");
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