On Mon, Feb 14, 2022 at 03:19:25PM +0800, Jason Wang wrote:
>
> 在 2022/2/3 下午3:27, Zhu Lingshan 写道:
> > On some platforms/devices, there may not be enough MSI vector
> > slots allocated for virtqueues and config changes. In such a case,
> > the interrupt sources(virtqueues, config changes) must share
> > an IRQ/vector, to avoid initialization failures, keep
> > the device functional.
> >
> > This commit handles three cases:
> > (1) number of the allocated vectors == the number of virtqueues + 1
> > (config changes), every virtqueue and the config interrupt has
> > a separated vector/IRQ, the best and the most likely case.
> > (2) number of the allocated vectors is less than the best case, but
> > greater than 1. In this case, all virtqueues share a vector/IRQ,
> > the config interrupt has a separated vector/IRQ
> > (3) only one vector is allocated, in this case, the virtqueues and
> > the config interrupt share a vector/IRQ. The worst and most
> > unlikely case.
> >
> > Otherwise, it needs to fail.
> >
> > This commit introduces some helper functions:
> > ifcvf_set_vq_vector() and ifcvf_set_config_vector() sets virtqueue
> > vector and config vector in the device config space, so that
> > the device can send interrupt DMA.
> >
> > This commit adds some fields in struct ifcvf_hw and re-placed
> > the existed fields to be aligned with the cacheline.
> >
> > Signed-off-by: Zhu Lingshan <lingshan.zhu@xxxxxxxxx>
> > ---
> > drivers/vdpa/ifcvf/ifcvf_base.c | 47 ++++--
> > drivers/vdpa/ifcvf/ifcvf_base.h | 23 ++-
> > drivers/vdpa/ifcvf/ifcvf_main.c | 243 +++++++++++++++++++++++++++-----
> > 3 files changed, 256 insertions(+), 57 deletions(-)
> >
> > diff --git a/drivers/vdpa/ifcvf/ifcvf_base.c b/drivers/vdpa/ifcvf/ifcvf_base.c
> > index 397692ae671c..18dcb63ab1e3 100644
> > --- a/drivers/vdpa/ifcvf/ifcvf_base.c
> > +++ b/drivers/vdpa/ifcvf/ifcvf_base.c
> > @@ -15,6 +15,36 @@ struct ifcvf_adapter *vf_to_adapter(struct ifcvf_hw *hw)
> > return container_of(hw, struct ifcvf_adapter, vf);
> > }
> > +int ifcvf_set_vq_vector(struct ifcvf_hw *hw, u16 qid, int vector)
> > +{
> > + struct virtio_pci_common_cfg __iomem *cfg = hw->common_cfg;
> > + struct ifcvf_adapter *ifcvf = vf_to_adapter(hw);
> > +
> > + ifc_iowrite16(qid, &cfg->queue_select);
> > + ifc_iowrite16(vector, &cfg->queue_msix_vector);
> > + if (ifc_ioread16(&cfg->queue_msix_vector) == VIRTIO_MSI_NO_VECTOR) {
> > + IFCVF_ERR(ifcvf->pdev, "No msix vector for queue %u\n", qid);
> > + return -EINVAL;
> > + }
>
>
> Let's leave this check for the caller, E.g can caller try to assign
> NO_VECTOR during uni-nit?
Hmm I'm not sure I agree. Caller will have to write queue select
again, and that's an extra IO, which is a waste.
And having function checking itself just seems better contained.
>
> > +
> > + return 0;
> > +}
> > +
> > +int ifcvf_set_config_vector(struct ifcvf_hw *hw, int vector)
> > +{
> > + struct virtio_pci_common_cfg __iomem *cfg = hw->common_cfg;
> > + struct ifcvf_adapter *ifcvf = vf_to_adapter(hw);
> > +
> > + cfg = hw->common_cfg;
> > + ifc_iowrite16(vector, &cfg->msix_config);
> > + if (ifc_ioread16(&cfg->msix_config) == VIRTIO_MSI_NO_VECTOR) {
> > + IFCVF_ERR(ifcvf->pdev, "No msix vector for device config\n");
> > + return -EINVAL;
> > + }
>
>
> Similar question as above.
>
>
> > +
> > + return 0;
> > +}
> > +
> > static void __iomem *get_cap_addr(struct ifcvf_hw *hw,
> > struct virtio_pci_cap *cap)
> > {
> > @@ -140,6 +170,8 @@ int ifcvf_init_hw(struct ifcvf_hw *hw, struct pci_dev *pdev)
> > hw->common_cfg, hw->notify_base, hw->isr,
> > hw->dev_cfg, hw->notify_off_multiplier);
> > + hw->vqs_shared_irq = -EINVAL;
> > +
> > return 0;
> > }
> > @@ -321,12 +353,6 @@ static int ifcvf_hw_enable(struct ifcvf_hw *hw)
> > ifcvf = vf_to_adapter(hw);
> > cfg = hw->common_cfg;
> > - ifc_iowrite16(IFCVF_MSI_CONFIG_OFF, &cfg->msix_config);
> > -
> > - if (ifc_ioread16(&cfg->msix_config) == VIRTIO_MSI_NO_VECTOR) {
> > - IFCVF_ERR(ifcvf->pdev, "No msix vector for device config\n");
> > - return -EINVAL;
> > - }
> > for (i = 0; i < hw->nr_vring; i++) {
> > if (!hw->vring[i].ready)
> > @@ -340,15 +366,6 @@ static int ifcvf_hw_enable(struct ifcvf_hw *hw)
> > ifc_iowrite64_twopart(hw->vring[i].used, &cfg->queue_used_lo,
> > &cfg->queue_used_hi);
> > ifc_iowrite16(hw->vring[i].size, &cfg->queue_size);
> > - ifc_iowrite16(i + IFCVF_MSI_QUEUE_OFF, &cfg->queue_msix_vector);
> > -
> > - if (ifc_ioread16(&cfg->queue_msix_vector) ==
> > - VIRTIO_MSI_NO_VECTOR) {
> > - IFCVF_ERR(ifcvf->pdev,
> > - "No msix vector for queue %u\n", i);
> > - return -EINVAL;
> > - }
> > -
> > ifcvf_set_vq_state(hw, i, hw->vring[i].last_avail_idx);
> > ifc_iowrite16(1, &cfg->queue_enable);
> > }
> > diff --git a/drivers/vdpa/ifcvf/ifcvf_base.h b/drivers/vdpa/ifcvf/ifcvf_base.h
> > index 949b4fb9d554..9cfe088c82e9 100644
> > --- a/drivers/vdpa/ifcvf/ifcvf_base.h
> > +++ b/drivers/vdpa/ifcvf/ifcvf_base.h
> > @@ -27,8 +27,6 @@
> > #define IFCVF_QUEUE_ALIGNMENT PAGE_SIZE
> > #define IFCVF_QUEUE_MAX 32768
> > -#define IFCVF_MSI_CONFIG_OFF 0
> > -#define IFCVF_MSI_QUEUE_OFF 1
> > #define IFCVF_PCI_MAX_RESOURCE 6
> > #define IFCVF_LM_CFG_SIZE 0x40
> > @@ -42,6 +40,13 @@
> > #define ifcvf_private_to_vf(adapter) \
> > (&((struct ifcvf_adapter *)adapter)->vf)
> > +/* all vqs and config interrupt has its own vector */
> > +#define MSIX_VECTOR_PER_VQ_AND_CONFIG 1
> > +/* all vqs share a vector, and config interrupt has a separate vector */
> > +#define MSIX_VECTOR_SHARED_VQ_AND_CONFIG 2
> > +/* all vqs and config interrupt share a vector */
> > +#define MSIX_VECTOR_DEV_SHARED 3
>
>
> I think there's no much value to differ 2 from 3 consider config interrupt
> should be rare.
Yes but if we do not have a dedicated vector then we need an
extra device IO (in fact, a read) on each interrupt.
>
> > +
> > static inline u8 ifc_ioread8(u8 __iomem *addr)
> > {
> > return ioread8(addr);
> > @@ -97,25 +102,27 @@ struct ifcvf_hw {
> > u8 __iomem *isr;
> > /* Live migration */
> > u8 __iomem *lm_cfg;
> > - u16 nr_vring;
>
>
> Any reason for moving nv_vring, config_size, and other stuffs?
>
>
> > /* Notification bar number */
> > u8 notify_bar;
> > + u8 msix_vector_status;
> > + /* virtio-net or virtio-blk device config size */
> > + u32 config_size;
> > /* Notificaiton bar address */
> > void __iomem *notify_base;
> > phys_addr_t notify_base_pa;
> > u32 notify_off_multiplier;
> > + u32 dev_type;
> > u64 req_features;
> > u64 hw_features;
> > - u32 dev_type;
> > struct virtio_pci_common_cfg __iomem *common_cfg;
> > void __iomem *dev_cfg;
> > struct vring_info vring[IFCVF_MAX_QUEUES];
> > void __iomem * const *base;
> > char config_msix_name[256];
> > struct vdpa_callback config_cb;
> > - unsigned int config_irq;
> > - /* virtio-net or virtio-blk device config size */
> > - u32 config_size;
> > + int config_irq;
> > + int vqs_shared_irq;
> > + u16 nr_vring;
> > };
> > struct ifcvf_adapter {
> > @@ -160,4 +167,6 @@ int ifcvf_set_vq_state(struct ifcvf_hw *hw, u16 qid, u16 num);
> > struct ifcvf_adapter *vf_to_adapter(struct ifcvf_hw *hw);
> > int ifcvf_probed_virtio_net(struct ifcvf_hw *hw);
> > u32 ifcvf_get_config_size(struct ifcvf_hw *hw);
> > +int ifcvf_set_vq_vector(struct ifcvf_hw *hw, u16 qid, int vector);
> > +int ifcvf_set_config_vector(struct ifcvf_hw *hw, int vector);
> > #endif /* _IFCVF_H_ */
> > diff --git a/drivers/vdpa/ifcvf/ifcvf_main.c b/drivers/vdpa/ifcvf/ifcvf_main.c
> > index 44c89ab0b6da..ca414399f040 100644
> > --- a/drivers/vdpa/ifcvf/ifcvf_main.c
> > +++ b/drivers/vdpa/ifcvf/ifcvf_main.c
> > @@ -17,6 +17,7 @@
> > #define DRIVER_AUTHOR "Intel Corporation"
> > #define IFCVF_DRIVER_NAME "ifcvf"
> > +/* handles config interrupt */
>
>
> This seems unrelated to the shared IRQ logic and it looks useless since it's
> easily to deduce it from the function name below.
>
>
> > static irqreturn_t ifcvf_config_changed(int irq, void *arg)
> > {
> > struct ifcvf_hw *vf = arg;
> > @@ -27,6 +28,7 @@ static irqreturn_t ifcvf_config_changed(int irq, void *arg)
> > return IRQ_HANDLED;
> > }
> > +/* handles vqs interrupt */
>
>
> So did this.
>
>
> > static irqreturn_t ifcvf_intr_handler(int irq, void *arg)
> > {
> > struct vring_info *vring = arg;
> > @@ -37,24 +39,78 @@ static irqreturn_t ifcvf_intr_handler(int irq, void *arg)
> > return IRQ_HANDLED;
> > }
> > +/* handls vqs shared interrupt */
> > +static irqreturn_t ifcvf_vq_shared_intr_handler(int irq, void *arg)
> > +{
> > + struct ifcvf_hw *vf = arg;
> > + struct vring_info *vring;
> > + int i;
> > +
> > + for (i = 0; i < vf->nr_vring; i++) {
> > + vring = &vf->vring[i];
> > + if (vring->cb.callback)
> > + vf->vring->cb.callback(vring->cb.private);
> > + }
> > +
> > + return IRQ_HANDLED;
> > +}
> > +
> > +/* handles a shared interrupt for vqs and config */
> > +static irqreturn_t ifcvf_dev_shared_intr_handler(int irq, void *arg)
shared is not a good name given IRQ_SHARED is not set.
maybe "common"? "reused"?
> > +{
> > + struct ifcvf_hw *vf = arg;
> > + u8 isr;
> > +
> > + isr = ifc_ioread8(vf->isr);
>
>
> We need to exactly what vp_interrupt do here. Checking against vf->isr first
> and return IRQ_NONE if it is not set.
no, vf->isr is not set for VQ interrupts. If need to actually poke
at the VQ to know.
> Always return IRQ_HANDLED will break the device who shares an irq with
> IFCVF.
It's a MSI, not INT#. So interrupt is not shared as such - it's only
sharing vector between config and vq.
>
> > + if (isr & VIRTIO_PCI_ISR_CONFIG)
> > + ifcvf_config_changed(irq, arg);
> > +
> > + return ifcvf_vq_shared_intr_handler(irq, arg);
> > +}
> > +
> > static void ifcvf_free_irq_vectors(void *data)
> > {
> > pci_free_irq_vectors(data);
> > }
> > -static void ifcvf_free_irq(struct ifcvf_adapter *adapter, int queues)
> > +static void ifcvf_free_vq_irq(struct ifcvf_adapter *adapter, int queues)
> > {
> > struct pci_dev *pdev = adapter->pdev;
> > struct ifcvf_hw *vf = &adapter->vf;
> > int i;
> > + if (vf->msix_vector_status == MSIX_VECTOR_PER_VQ_AND_CONFIG) {
> > + for (i = 0; i < queues; i++) {
> > + devm_free_irq(&pdev->dev, vf->vring[i].irq, &vf->vring[i]);
> > + vf->vring[i].irq = -EINVAL;
> > + }
> > + } else {
> > + devm_free_irq(&pdev->dev, vf->vqs_shared_irq, vf);
> > + vf->vqs_shared_irq = -EINVAL;
> > + }
> > +}
> > - for (i = 0; i < queues; i++) {
> > - devm_free_irq(&pdev->dev, vf->vring[i].irq, &vf->vring[i]);
> > - vf->vring[i].irq = -EINVAL;
> > +static void ifcvf_free_config_irq(struct ifcvf_adapter *adapter)
> > +{
> > + struct pci_dev *pdev = adapter->pdev;
> > + struct ifcvf_hw *vf = &adapter->vf;
> > +
> > + /* If the irq is shared by all vqs and the config interrupt,
> > + * it is already freed in ifcvf_free_vq_irq, so here only
> > + * need to free config irq when msix_vector_status != MSIX_VECTOR_DEV_SHARED
> > + */
> > + if (vf->msix_vector_status != MSIX_VECTOR_DEV_SHARED) {
> > + devm_free_irq(&pdev->dev, vf->config_irq, vf);
> > + vf->config_irq = -EINVAL;
> > }
> > +}
> > +
> > +static void ifcvf_free_irq(struct ifcvf_adapter *adapter, int queues)
> > +{
> > + struct pci_dev *pdev = adapter->pdev;
> > - devm_free_irq(&pdev->dev, vf->config_irq, vf);
> > + ifcvf_free_vq_irq(adapter, queues);
> > + ifcvf_free_config_irq(adapter);
> > ifcvf_free_irq_vectors(pdev);
> > }
> > @@ -86,58 +142,172 @@ static int ifcvf_alloc_vectors(struct ifcvf_adapter *adapter)
> > return ret;
> > }
> > -static int ifcvf_request_irq(struct ifcvf_adapter *adapter)
> > +static int ifcvf_request_per_vq_irq(struct ifcvf_adapter *adapter)
> > {
> > struct pci_dev *pdev = adapter->pdev;
> > struct ifcvf_hw *vf = &adapter->vf;
> > - int vector, nvectors, i, ret, irq;
> > - u16 max_intr;
> > + int i, vector, ret, irq;
> > - nvectors = ifcvf_alloc_vectors(adapter);
> > - if (!(nvectors > 0))
> > - return nvectors;
> > + for (i = 0; i < vf->nr_vring; i++) {
> > + snprintf(vf->vring[i].msix_name, 256, "ifcvf[%s]-%d\n", pci_name(pdev), i);
> > + vector = i;
> > + 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_vq_irq(adapter, i);
> > + } else {
> > + vf->vring[i].irq = irq;
> > + ifcvf_set_vq_vector(vf, i, vector);
> > + }
> > + }
> > - max_intr = vf->nr_vring + 1;
> > + vf->vqs_shared_irq = -EINVAL;
> > +
> > + return 0;
> > +}
> > +
> > +static int ifcvf_request_shared_vq_irq(struct ifcvf_adapter *adapter)
> > +{
> > + struct pci_dev *pdev = adapter->pdev;
> > + struct ifcvf_hw *vf = &adapter->vf;
> > + int i, vector, ret, irq;
> > +
> > + vector = 0;
> > + /* reuse msix_name[256] space of vring0 to store shared vqs interrupt name */
>
>
> I think we can remove this comment since the code is straightforward.
>
>
> > + snprintf(vf->vring[0].msix_name, 256, "ifcvf[%s]-vqs-shared-irq\n", pci_name(pdev));
> > + irq = pci_irq_vector(pdev, vector);
> > + ret = devm_request_irq(&pdev->dev, irq,
> > + ifcvf_vq_shared_intr_handler, 0,
> > + vf->vring[0].msix_name, vf);
> > + if (ret) {
> > + IFCVF_ERR(pdev, "Failed to request shared irq for vf\n");
> > +
> > + return ret;
> > + }
> > +
> > + vf->vqs_shared_irq = irq;
> > + for (i = 0; i < vf->nr_vring; i++) {
> > + vf->vring[i].irq = -EINVAL;
> > + ifcvf_set_vq_vector(vf, i, vector);
> > + }
> > +
> > + return 0;
> > +
> > +}
> > +
> > +static int ifcvf_request_dev_shared_irq(struct ifcvf_adapter *adapter)
> > +{
> > + struct pci_dev *pdev = adapter->pdev;
> > + struct ifcvf_hw *vf = &adapter->vf;
> > + int i, vector, ret, irq;
> > +
> > + vector = 0;
> > + /* reuse msix_name[256] space of vring0 to store shared device interrupt name */
> > + snprintf(vf->vring[0].msix_name, 256, "ifcvf[%s]-dev-shared-irq\n", pci_name(pdev));
> > + irq = pci_irq_vector(pdev, vector);
> > + ret = devm_request_irq(&pdev->dev, irq,
> > + ifcvf_dev_shared_intr_handler, 0,
> > + vf->vring[0].msix_name, vf);
> > + if (ret) {
> > + IFCVF_ERR(pdev, "Failed to request shared irq for vf\n");
> > - ret = pci_alloc_irq_vectors(pdev, max_intr,
> > - max_intr, PCI_IRQ_MSIX);
> > - if (ret < 0) {
> > - IFCVF_ERR(pdev, "Failed to alloc IRQ vectors\n");
> > return ret;
> > }
> > + vf->vqs_shared_irq = irq;
> > + for (i = 0; i < vf->nr_vring; i++) {
> > + vf->vring[i].irq = -EINVAL;
> > + ifcvf_set_vq_vector(vf, i, vector);
> > + }
> > +
> > + vf->config_irq = irq;
> > + ifcvf_set_config_vector(vf, vector);
> > +
> > + return 0;
> > +
> > +}
> > +
> > +static int ifcvf_request_vq_irq(struct ifcvf_adapter *adapter)
> > +{
> > + struct ifcvf_hw *vf = &adapter->vf;
> > + int ret;
> > +
> > + if (vf->msix_vector_status == MSIX_VECTOR_PER_VQ_AND_CONFIG)
> > + ret = ifcvf_request_per_vq_irq(adapter);
> > + else
> > + ret = ifcvf_request_shared_vq_irq(adapter);
> > +
> > + return ret;
> > +}
> > +
> > +static int ifcvf_request_config_irq(struct ifcvf_adapter *adapter)
> > +{
> > + struct pci_dev *pdev = adapter->pdev;
> > + struct ifcvf_hw *vf = &adapter->vf;
> > + int config_vector, ret;
> > +
> > + if (vf->msix_vector_status == MSIX_VECTOR_DEV_SHARED)
> > + return 0;
> > +
> > + if (vf->msix_vector_status == MSIX_VECTOR_PER_VQ_AND_CONFIG)
> > + /* vector 0 ~ vf->nr_vring for vqs, num vf->nr_vring vector for config interrupt */
> > + config_vector = vf->nr_vring;
> > +
> > + if (vf->msix_vector_status == MSIX_VECTOR_SHARED_VQ_AND_CONFIG)
> > + /* vector 0 for vqs and 1 for config interrupt */
> > + config_vector = 1;
> > +
> > snprintf(vf->config_msix_name, 256, "ifcvf[%s]-config\n",
> > pci_name(pdev));
> > - vector = 0;
> > - vf->config_irq = pci_irq_vector(pdev, vector);
> > + vf->config_irq = pci_irq_vector(pdev, config_vector);
> > ret = devm_request_irq(&pdev->dev, vf->config_irq,
> > ifcvf_config_changed, 0,
> > vf->config_msix_name, vf);
> > if (ret) {
> > IFCVF_ERR(pdev, "Failed to request config irq\n");
> > + ifcvf_free_vq_irq(adapter, vf->nr_vring);
> > return ret;
> > }
> > - for (i = 0; i < vf->nr_vring; 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);
> > + ifcvf_set_config_vector(vf, config_vector);
> > - return ret;
> > - }
> > + return 0;
> > +}
> > +
> > +static int ifcvf_request_irq(struct ifcvf_adapter *adapter)
> > +{
>
>
> As replied above, I think having two modes should be sufficient and the code
> could be greatly simplified.
>
> Thanks
>
Well it is claimed there are platforms where we are short
on vectors. 3 versus 2 seems a 50% saving. You disagree?
> > + struct ifcvf_hw *vf = &adapter->vf;
> > + int nvectors, ret, max_intr;
> > - vf->vring[i].irq = irq;
> > + nvectors = ifcvf_alloc_vectors(adapter);
> > + if (!(nvectors > 0))
> > + return nvectors;
> > +
> > + vf->msix_vector_status = MSIX_VECTOR_PER_VQ_AND_CONFIG;
> > + max_intr = vf->nr_vring + 1;
> > + if (nvectors < max_intr)
> > + vf->msix_vector_status = MSIX_VECTOR_SHARED_VQ_AND_CONFIG;
> > +
> > + if (nvectors == 1) {
> > + vf->msix_vector_status = MSIX_VECTOR_DEV_SHARED;
> > + ret = ifcvf_request_dev_shared_irq(adapter);
> > +
> > + return ret;
> > }
> > + ret = ifcvf_request_vq_irq(adapter);
> > + if (ret)
> > + return ret;
> > +
> > + ret = ifcvf_request_config_irq(adapter);
> > +
> > + if (ret)
> > + return ret;
> > +
> > return 0;
> > }
> > @@ -441,7 +611,10 @@ static int ifcvf_vdpa_get_vq_irq(struct vdpa_device *vdpa_dev,
> > {
> > struct ifcvf_hw *vf = vdpa_to_vf(vdpa_dev);
> > - return vf->vring[qid].irq;
> > + if (vf->vqs_shared_irq < 0)
> > + return vf->vring[qid].irq;
> > + else
> > + return -EINVAL;
> > }
> > static struct vdpa_notification_area ifcvf_get_vq_notification(struct vdpa_device *vdpa_dev,
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