[PATCH V2 0/4] vDPA/ifcvf: implement shared IRQ feature

[PATCH V2 0/4] vDPA/ifcvf: implement shared IRQ feature

[Zhu Lingshan]

It has been observed that on some platforms/devices, there may
not be enough MSI vectors for virtqueues and the config change.
Under such circumstances, the interrupt sources of a device
have to share vectors/IRQs.

This series implemented a shared IRQ feature for ifcvf.

Please help review.

Changes from V1:
(1) Enable config interrupt when only one vector is allocated(Michael)
(2) Clean vectors/IRQs if failed to request config interrupt
since config interrupt is a must(Michael)
(3) Keep local vdpa_ops, disable irq_bypass by setting IRQ = -EINVAL
for shared IRQ case(Michael)
(4) Improvements on error messages(Michael)
(5) Squash functions implementation patches to the callers(Michael)

Zhu Lingshan (4):
  vDPA/ifcvf: implement IO read/write helpers in the header file
  vDPA/ifcvf: implement device MSIX vector allocator
  vhost_vdpa: don't setup irq offloading when irq_num < 0
  vDPA/ifcvf: implement shared IRQ feature

 drivers/vdpa/ifcvf/ifcvf_base.c |  67 +++------
 drivers/vdpa/ifcvf/ifcvf_base.h |  60 +++++++-
 drivers/vdpa/ifcvf/ifcvf_main.c | 254 ++++++++++++++++++++++++++++----
 drivers/vhost/vdpa.c            |   3 +
 4 files changed, 305 insertions(+), 79 deletions(-)

-- 
2.27.0

[PATCH V2 1/4] vDPA/ifcvf: implement IO read/write helpers in the header file

[Zhu Lingshan]

re-implement IO read/write helpers in the header file, so that
they can be utilized among modules.

Signed-off-by: Zhu Lingshan <lingshan.zhu@intel.com>
---
 drivers/vdpa/ifcvf/ifcvf_base.c | 36 --------------------------------
 drivers/vdpa/ifcvf/ifcvf_base.h | 37 +++++++++++++++++++++++++++++++++
 2 files changed, 37 insertions(+), 36 deletions(-)

diff --git a/drivers/vdpa/ifcvf/ifcvf_base.c b/drivers/vdpa/ifcvf/ifcvf_base.c
index 7d41dfe48ade..397692ae671c 100644
--- a/drivers/vdpa/ifcvf/ifcvf_base.c
+++ b/drivers/vdpa/ifcvf/ifcvf_base.c
@@ -10,42 +10,6 @@
 
 #include "ifcvf_base.h"
 
-static inline u8 ifc_ioread8(u8 __iomem *addr)
-{
-	return ioread8(addr);
-}
-static inline u16 ifc_ioread16 (__le16 __iomem *addr)
-{
-	return ioread16(addr);
-}
-
-static inline u32 ifc_ioread32(__le32 __iomem *addr)
-{
-	return ioread32(addr);
-}
-
-static inline void ifc_iowrite8(u8 value, u8 __iomem *addr)
-{
-	iowrite8(value, addr);
-}
-
-static inline void ifc_iowrite16(u16 value, __le16 __iomem *addr)
-{
-	iowrite16(value, addr);
-}
-
-static inline void ifc_iowrite32(u32 value, __le32 __iomem *addr)
-{
-	iowrite32(value, addr);
-}
-
-static void ifc_iowrite64_twopart(u64 val,
-				  __le32 __iomem *lo, __le32 __iomem *hi)
-{
-	ifc_iowrite32((u32)val, lo);
-	ifc_iowrite32(val >> 32, hi);
-}
-
 struct ifcvf_adapter *vf_to_adapter(struct ifcvf_hw *hw)
 {
 	return container_of(hw, struct ifcvf_adapter, vf);
diff --git a/drivers/vdpa/ifcvf/ifcvf_base.h b/drivers/vdpa/ifcvf/ifcvf_base.h
index c486873f370a..949b4fb9d554 100644
--- a/drivers/vdpa/ifcvf/ifcvf_base.h
+++ b/drivers/vdpa/ifcvf/ifcvf_base.h
@@ -42,6 +42,43 @@
 #define ifcvf_private_to_vf(adapter) \
 	(&((struct ifcvf_adapter *)adapter)->vf)
 
+static inline u8 ifc_ioread8(u8 __iomem *addr)
+{
+	return ioread8(addr);
+}
+
+static inline u16 ifc_ioread16(__le16 __iomem *addr)
+{
+	return ioread16(addr);
+}
+
+static inline u32 ifc_ioread32(__le32 __iomem *addr)
+{
+	return ioread32(addr);
+}
+
+static inline void ifc_iowrite8(u8 value, u8 __iomem *addr)
+{
+	iowrite8(value, addr);
+}
+
+static inline void ifc_iowrite16(u16 value, __le16 __iomem *addr)
+{
+	iowrite16(value, addr);
+}
+
+static inline void ifc_iowrite32(u32 value, __le32 __iomem *addr)
+{
+	iowrite32(value, addr);
+}
+
+static inline void ifc_iowrite64_twopart(u64 val,
+				  __le32 __iomem *lo, __le32 __iomem *hi)
+{
+	ifc_iowrite32((u32)val, lo);
+	ifc_iowrite32(val >> 32, hi);
+}
+
 struct vring_info {
 	u64 desc;
 	u64 avail;
-- 
2.27.0

[PATCH V2 2/4] vDPA/ifcvf: implement device MSIX vector allocator

[Zhu Lingshan]

This commit implements a MSIX vector allocation helper
for vqs and config interrupts.

Signed-off-by: Zhu Lingshan <lingshan.zhu@intel.com>
---
 drivers/vdpa/ifcvf/ifcvf_main.c | 30 ++++++++++++++++++++++++++++--
 1 file changed, 28 insertions(+), 2 deletions(-)

diff --git a/drivers/vdpa/ifcvf/ifcvf_main.c b/drivers/vdpa/ifcvf/ifcvf_main.c
index d1a6b5ab543c..7e2af2d2aaf5 100644
--- a/drivers/vdpa/ifcvf/ifcvf_main.c
+++ b/drivers/vdpa/ifcvf/ifcvf_main.c
@@ -58,14 +58,40 @@ static void ifcvf_free_irq(struct ifcvf_adapter *adapter, int queues)
 	ifcvf_free_irq_vectors(pdev);
 }
 
+static int ifcvf_alloc_vectors(struct ifcvf_adapter *adapter)
+{
+	struct pci_dev *pdev = adapter->pdev;
+	struct ifcvf_hw *vf = &adapter->vf;
+	u16 max_intr, ret;
+
+	/* all queues and config interrupt  */
+	max_intr = vf->nr_vring + 1;
+	ret = pci_alloc_irq_vectors(pdev, 1, max_intr, PCI_IRQ_MSIX | PCI_IRQ_AFFINITY);
+
+	if (ret < 0) {
+		IFCVF_ERR(pdev, "Failed to alloc IRQ vectors\n");
+		return ret;
+	}
+
+	if (ret < max_intr)
+		IFCVF_INFO(pdev,
+			   "Requested %u vectors, however only %u allocated, lower performance\n",
+			   max_intr, ret);
+
+	return ret;
+}
+
 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;
-	u16 max_intr;
+	u16 nvectors, max_intr;
+
+	nvectors = ifcvf_alloc_vectors(adapter);
+	if (!(nvectors > 0))
+		return nvectors;
 
-	/* all queues and config interrupt  */
 	max_intr = vf->nr_vring + 1;
 
 	ret = pci_alloc_irq_vectors(pdev, max_intr,
-- 
2.27.0

Re: [PATCH V2 2/4] vDPA/ifcvf: implement device MSIX vector allocator

[Michael S. Tsirkin]

On Tue, Jan 25, 2022 at 05:17:42PM +0800, Zhu Lingshan wrote:
> This commit implements a MSIX vector allocation helper
> for vqs and config interrupts.
> 
> Signed-off-by: Zhu Lingshan <lingshan.zhu@intel.com>
> ---
>  drivers/vdpa/ifcvf/ifcvf_main.c | 30 ++++++++++++++++++++++++++++--
>  1 file changed, 28 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/vdpa/ifcvf/ifcvf_main.c b/drivers/vdpa/ifcvf/ifcvf_main.c
> index d1a6b5ab543c..7e2af2d2aaf5 100644
> --- a/drivers/vdpa/ifcvf/ifcvf_main.c
> +++ b/drivers/vdpa/ifcvf/ifcvf_main.c
> @@ -58,14 +58,40 @@ static void ifcvf_free_irq(struct ifcvf_adapter *adapter, int queues)
>  	ifcvf_free_irq_vectors(pdev);
>  }
>  
> +static int ifcvf_alloc_vectors(struct ifcvf_adapter *adapter)


So the helper returns an int...

> +{
> +	struct pci_dev *pdev = adapter->pdev;
> +	struct ifcvf_hw *vf = &adapter->vf;
> +	u16 max_intr, ret;
> +
> +	/* all queues and config interrupt  */
> +	max_intr = vf->nr_vring + 1;
> +	ret = pci_alloc_irq_vectors(pdev, 1, max_intr, PCI_IRQ_MSIX | PCI_IRQ_AFFINITY);
> +
> +	if (ret < 0) {
> +		IFCVF_ERR(pdev, "Failed to alloc IRQ vectors\n");
> +		return ret;


which is negative on error...

> +	}
> +
> +	if (ret < max_intr)
> +		IFCVF_INFO(pdev,
> +			   "Requested %u vectors, however only %u allocated, lower performance\n",
> +			   max_intr, ret);
> +
> +	return ret;
> +}
> +
>  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;
> -	u16 max_intr;
> +	u16 nvectors, max_intr;
> +
> +	nvectors = ifcvf_alloc_vectors(adapter);

which you proceed to stash into an unsigned int ...

> +	if (!(nvectors > 0))

and then compare to zero ...

> +		return nvectors;
>

correct error handling is unlikely as a result.

  
> -	/* all queues and config interrupt  */
>  	max_intr = vf->nr_vring + 1;
>  
>  	ret = pci_alloc_irq_vectors(pdev, max_intr,


As long as you are introducing a helper, document it's return
type and behaviour and then use correctly.

> -- 
> 2.27.0

Re: [PATCH V2 2/4] vDPA/ifcvf: implement device MSIX vector allocator

[Zhu, Lingshan]

On 1/26/2022 3:36 AM, Michael S. Tsirkin wrote:
> On Tue, Jan 25, 2022 at 05:17:42PM +0800, Zhu Lingshan wrote:
>> This commit implements a MSIX vector allocation helper
>> for vqs and config interrupts.
>>
>> Signed-off-by: Zhu Lingshan <lingshan.zhu@intel.com>
>> ---
>>   drivers/vdpa/ifcvf/ifcvf_main.c | 30 ++++++++++++++++++++++++++++--
>>   1 file changed, 28 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/vdpa/ifcvf/ifcvf_main.c b/drivers/vdpa/ifcvf/ifcvf_main.c
>> index d1a6b5ab543c..7e2af2d2aaf5 100644
>> --- a/drivers/vdpa/ifcvf/ifcvf_main.c
>> +++ b/drivers/vdpa/ifcvf/ifcvf_main.c
>> @@ -58,14 +58,40 @@ static void ifcvf_free_irq(struct ifcvf_adapter *adapter, int queues)
>>   	ifcvf_free_irq_vectors(pdev);
>>   }
>>   
>> +static int ifcvf_alloc_vectors(struct ifcvf_adapter *adapter)
>
> So the helper returns an int...
can fix in V3, thanks for your help!
>
>> +{
>> +	struct pci_dev *pdev = adapter->pdev;
>> +	struct ifcvf_hw *vf = &adapter->vf;
>> +	u16 max_intr, ret;
>> +
>> +	/* all queues and config interrupt  */
>> +	max_intr = vf->nr_vring + 1;
>> +	ret = pci_alloc_irq_vectors(pdev, 1, max_intr, PCI_IRQ_MSIX | PCI_IRQ_AFFINITY);
>> +
>> +	if (ret < 0) {
>> +		IFCVF_ERR(pdev, "Failed to alloc IRQ vectors\n");
>> +		return ret;
>
> which is negative on error...
>
>> +	}
>> +
>> +	if (ret < max_intr)
>> +		IFCVF_INFO(pdev,
>> +			   "Requested %u vectors, however only %u allocated, lower performance\n",
>> +			   max_intr, ret);
>> +
>> +	return ret;
>> +}
>> +
>>   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;
>> -	u16 max_intr;
>> +	u16 nvectors, max_intr;
>> +
>> +	nvectors = ifcvf_alloc_vectors(adapter);
> which you proceed to stash into an unsigned int ...
>
>> +	if (!(nvectors > 0))
> and then compare to zero ...
>
>> +		return nvectors;
>>
> correct error handling is unlikely as a result.
>
>    
>> -	/* all queues and config interrupt  */
>>   	max_intr = vf->nr_vring + 1;
>>   
>>   	ret = pci_alloc_irq_vectors(pdev, max_intr,
>
> As long as you are introducing a helper, document it's return
> type and behaviour and then use correctly.
>
>> -- 
>> 2.27.0

[PATCH V2 3/4] vhost_vdpa: don't setup irq offloading when irq_num < 0

[Zhu Lingshan]

When irq number is negative(e.g., -EINVAL), the virtqueue
may be disabled or the virtqueues are sharing a device irq.
In such case, we should not setup irq offloading for a virtqueue.

Signed-off-by: Zhu Lingshan <lingshan.zhu@intel.com>
---
 drivers/vhost/vdpa.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
index 851539807bc9..909891d518e8 100644
--- a/drivers/vhost/vdpa.c
+++ b/drivers/vhost/vdpa.c
@@ -96,6 +96,9 @@ static void vhost_vdpa_setup_vq_irq(struct vhost_vdpa *v, u16 qid)
 	if (!ops->get_vq_irq)
 		return;
 
+	if (irq < 0)
+		return;
+
 	irq = ops->get_vq_irq(vdpa, qid);
 	irq_bypass_unregister_producer(&vq->call_ctx.producer);
 	if (!vq->call_ctx.ctx || irq < 0)
-- 
2.27.0

Re: [PATCH V2 3/4] vhost_vdpa: don't setup irq offloading when irq_num < 0

[kernel test robot]

Hi Zhu,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on mst-vhost/linux-next]
[also build test WARNING on horms-ipvs/master linus/master v5.17-rc1 next-20220125]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Zhu-Lingshan/vDPA-ifcvf-implement-shared-IRQ-feature/20220125-174020
base:   https://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost.git linux-next
config: arm-randconfig-c002-20220124 (https://download.01.org/0day-ci/archive/20220126/202201260245.1yTB6YwE-lkp@intel.com/config)
compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project 997e128e2a78f5a5434fc75997441ae1ee76f8a4)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # install arm cross compiling tool for clang build
        # apt-get install binutils-arm-linux-gnueabi
        # https://github.com/0day-ci/linux/commit/9242eae873643db8562d24857da7d05a2950ecfe
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Zhu-Lingshan/vDPA-ifcvf-implement-shared-IRQ-feature/20220125-174020
        git checkout 9242eae873643db8562d24857da7d05a2950ecfe
        # save the config file to linux build tree
        mkdir build_dir
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=arm SHELL=/bin/bash drivers/vhost/

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

>> drivers/vhost/vdpa.c:99:6: warning: variable 'irq' is uninitialized when used here [-Wuninitialized]
           if (irq < 0)
               ^~~
   drivers/vhost/vdpa.c:94:14: note: initialize the variable 'irq' to silence this warning
           int ret, irq;
                       ^
                        = 0
   1 warning generated.


vim +/irq +99 drivers/vhost/vdpa.c

    88	
    89	static void vhost_vdpa_setup_vq_irq(struct vhost_vdpa *v, u16 qid)
    90	{
    91		struct vhost_virtqueue *vq = &v->vqs[qid];
    92		const struct vdpa_config_ops *ops = v->vdpa->config;
    93		struct vdpa_device *vdpa = v->vdpa;
    94		int ret, irq;
    95	
    96		if (!ops->get_vq_irq)
    97			return;
    98	
  > 99		if (irq < 0)
   100			return;
   101	
   102		irq = ops->get_vq_irq(vdpa, qid);
   103		irq_bypass_unregister_producer(&vq->call_ctx.producer);
   104		if (!vq->call_ctx.ctx || irq < 0)
   105			return;
   106	
   107		vq->call_ctx.producer.token = vq->call_ctx.ctx;
   108		vq->call_ctx.producer.irq = irq;
   109		ret = irq_bypass_register_producer(&vq->call_ctx.producer);
   110		if (unlikely(ret))
   111			dev_info(&v->dev, "vq %u, irq bypass producer (token %p) registration fails, ret =  %d\n",
   112				 qid, vq->call_ctx.producer.token, ret);
   113	}
   114	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

Re: [PATCH V2 3/4] vhost_vdpa: don't setup irq offloading when irq_num < 0

[Michael S. Tsirkin]

On Tue, Jan 25, 2022 at 05:17:43PM +0800, Zhu Lingshan wrote:
> When irq number is negative(e.g., -EINVAL), the virtqueue
> may be disabled or the virtqueues are sharing a device irq.
> In such case, we should not setup irq offloading for a virtqueue.
> 
> Signed-off-by: Zhu Lingshan <lingshan.zhu@intel.com>
> ---
>  drivers/vhost/vdpa.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
> index 851539807bc9..909891d518e8 100644
> --- a/drivers/vhost/vdpa.c
> +++ b/drivers/vhost/vdpa.c
> @@ -96,6 +96,9 @@ static void vhost_vdpa_setup_vq_irq(struct vhost_vdpa *v, u16 qid)
>  	if (!ops->get_vq_irq)
>  		return;
>  
> +	if (irq < 0)
> +		return;
> +
>  	irq = ops->get_vq_irq(vdpa, qid);

So it's used before it's initialized. Ugh.
How was this patchset tested?

>  	irq_bypass_unregister_producer(&vq->call_ctx.producer);
>  	if (!vq->call_ctx.ctx || irq < 0)
> -- 
> 2.27.0

Re: [PATCH V2 3/4] vhost_vdpa: don't setup irq offloading when irq_num < 0

[Zhu, Lingshan]

On 1/26/2022 3:30 AM, Michael S. Tsirkin wrote:
> On Tue, Jan 25, 2022 at 05:17:43PM +0800, Zhu Lingshan wrote:
>> When irq number is negative(e.g., -EINVAL), the virtqueue
>> may be disabled or the virtqueues are sharing a device irq.
>> In such case, we should not setup irq offloading for a virtqueue.
>>
>> Signed-off-by: Zhu Lingshan <lingshan.zhu@intel.com>
>> ---
>>   drivers/vhost/vdpa.c | 3 +++
>>   1 file changed, 3 insertions(+)
>>
>> diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
>> index 851539807bc9..909891d518e8 100644
>> --- a/drivers/vhost/vdpa.c
>> +++ b/drivers/vhost/vdpa.c
>> @@ -96,6 +96,9 @@ static void vhost_vdpa_setup_vq_irq(struct vhost_vdpa *v, u16 qid)
>>   	if (!ops->get_vq_irq)
>>   		return;
>>   
>> +	if (irq < 0)
>> +		return;
>> +
>>   	irq = ops->get_vq_irq(vdpa, qid);
> So it's used before it's initialized. Ugh.
> How was this patchset tested?
Sorry, my bad, it is not rebased properly, V3 can fix this for sure.

Thanks
>
>>   	irq_bypass_unregister_producer(&vq->call_ctx.producer);
>>   	if (!vq->call_ctx.ctx || irq < 0)
>> -- 
>> 2.27.0

[PATCH V2 4/4] vDPA/ifcvf: implement shared IRQ feature

[Zhu Lingshan]

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@intel.com>
---
 drivers/vdpa/ifcvf/ifcvf_base.c |  47 +++++--
 drivers/vdpa/ifcvf/ifcvf_base.h |  23 ++-
 drivers/vdpa/ifcvf/ifcvf_main.c | 240 +++++++++++++++++++++++++++-----
 3 files changed, 253 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;
+	}
+
+	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;
+	}
+
+	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..d2a2a526f0fc 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
+
 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;
 	/* 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;
+	u32 config_irq;
+	u32 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 7e2af2d2aaf5..c7070ff01776 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 */
 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 */
 static irqreturn_t ifcvf_intr_handler(int irq, void *arg)
 {
 	struct vring_info *vring = arg;
@@ -37,24 +39,77 @@ 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)
+{
+	struct ifcvf_hw *vf = arg;
+	u8 isr;
+
+	isr = ifc_ioread8(vf->isr);
+	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);
 }
 
@@ -81,58 +136,170 @@ 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, i, ret, irq;
-	u16 nvectors, 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;
+	irq = pci_irq_vector(pdev, vector);
+	ret = devm_request_irq(&pdev->dev, irq,
+			       ifcvf_vq_shared_intr_handler, 0,
+			       "ifcvf_vq_shared_irq",
+			       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;
+	irq = pci_irq_vector(pdev, vector);
+	ret = devm_request_irq(&pdev->dev, irq,
+			       ifcvf_dev_shared_intr_handler, 0,
+			       "ifcvf_dev_shared_irq",
+			       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;
 	}
+		ifcvf_set_config_vector(vf, config_vector);
 
-	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);
+	return 0;
+}
 
-			return ret;
-		}
+static int ifcvf_request_irq(struct ifcvf_adapter *adapter)
+{
+	struct ifcvf_hw *vf = &adapter->vf;
+	u16 nvectors, max_intr;
+	int ret;
 
-		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;
 }
 
@@ -436,7 +603,10 @@ 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,
-- 
2.27.0

Re: [PATCH V2 4/4] vDPA/ifcvf: implement shared IRQ feature

[Michael S. Tsirkin]

On Tue, Jan 25, 2022 at 05:17:44PM +0800, Zhu Lingshan wrote:
> 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@intel.com>
> ---
>  drivers/vdpa/ifcvf/ifcvf_base.c |  47 +++++--
>  drivers/vdpa/ifcvf/ifcvf_base.h |  23 ++-
>  drivers/vdpa/ifcvf/ifcvf_main.c | 240 +++++++++++++++++++++++++++-----
>  3 files changed, 253 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;
> +	}
> +
> +	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;
> +	}
> +
> +	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;
> +

This stuffing of errno values into u32 is not a good idea.


>  	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..d2a2a526f0fc 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
> +
>  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;
>  	/* 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;
> +	u32 config_irq;
> +	u32 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 7e2af2d2aaf5..c7070ff01776 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 */
>  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 */
>  static irqreturn_t ifcvf_intr_handler(int irq, void *arg)
>  {
>  	struct vring_info *vring = arg;
> @@ -37,24 +39,77 @@ 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)
> +{
> +	struct ifcvf_hw *vf = arg;
> +	u8 isr;
> +
> +	isr = ifc_ioread8(vf->isr);
> +	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;

If you use {} in the else branch, use it on the then branch, too.


> +}
>  
> -	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);
>  }
>  
> @@ -81,58 +136,170 @@ 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, i, ret, irq;
> -	u16 nvectors, 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;
> +	irq = pci_irq_vector(pdev, vector);
> +	ret = devm_request_irq(&pdev->dev, irq,
> +			       ifcvf_vq_shared_intr_handler, 0,
> +			       "ifcvf_vq_shared_irq",
> +			       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;
> +	irq = pci_irq_vector(pdev, vector);
> +	ret = devm_request_irq(&pdev->dev, irq,
> +			       ifcvf_dev_shared_intr_handler, 0,
> +			       "ifcvf_dev_shared_irq",
> +			       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;
>  	}
> +		ifcvf_set_config_vector(vf, config_vector);
>  
> -	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);
> +	return 0;
> +}
>  
> -			return ret;
> -		}
> +static int ifcvf_request_irq(struct ifcvf_adapter *adapter)

This function was not moved, was it?

Try --minimal or --histogram maybe. Or just
--anchored=ifcvf_request_irq


> +{
> +	struct ifcvf_hw *vf = &adapter->vf;
> +	u16 nvectors, max_intr;
> +	int ret;
>  
> -		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;
>  }
>  
> @@ -436,7 +603,10 @@ 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,
> -- 
> 2.27.0

Re: [PATCH V2 4/4] vDPA/ifcvf: implement shared IRQ feature

[Zhu, Lingshan]

On 1/26/2022 3:42 AM, Michael S. Tsirkin wrote:
> On Tue, Jan 25, 2022 at 05:17:44PM +0800, Zhu Lingshan wrote:
>> 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@intel.com>
>> ---
>>   drivers/vdpa/ifcvf/ifcvf_base.c |  47 +++++--
>>   drivers/vdpa/ifcvf/ifcvf_base.h |  23 ++-
>>   drivers/vdpa/ifcvf/ifcvf_main.c | 240 +++++++++++++++++++++++++++-----
>>   3 files changed, 253 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;
>> +	}
>> +
>> +	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;
>> +	}
>> +
>> +	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;
>> +
> This stuffing of errno values into u32 is not a good idea.
will fix this in V3
>
>
>>   	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..d2a2a526f0fc 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
>> +
>>   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;
>>   	/* 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;
>> +	u32 config_irq;
>> +	u32 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 7e2af2d2aaf5..c7070ff01776 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 */
>>   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 */
>>   static irqreturn_t ifcvf_intr_handler(int irq, void *arg)
>>   {
>>   	struct vring_info *vring = arg;
>> @@ -37,24 +39,77 @@ 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)
>> +{
>> +	struct ifcvf_hw *vf = arg;
>> +	u8 isr;
>> +
>> +	isr = ifc_ioread8(vf->isr);
>> +	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;
> If you use {} in the else branch, use it on the then branch, too.
sure
>
>
>> +}
>>   
>> -	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);
>>   }
>>   
>> @@ -81,58 +136,170 @@ 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, i, ret, irq;
>> -	u16 nvectors, 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;
>> +	irq = pci_irq_vector(pdev, vector);
>> +	ret = devm_request_irq(&pdev->dev, irq,
>> +			       ifcvf_vq_shared_intr_handler, 0,
>> +			       "ifcvf_vq_shared_irq",
>> +			       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;
>> +	irq = pci_irq_vector(pdev, vector);
>> +	ret = devm_request_irq(&pdev->dev, irq,
>> +			       ifcvf_dev_shared_intr_handler, 0,
>> +			       "ifcvf_dev_shared_irq",
>> +			       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;
>>   	}
>> +		ifcvf_set_config_vector(vf, config_vector);
>>   
>> -	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);
>> +	return 0;
>> +}
>>   
>> -			return ret;
>> -		}
>> +static int ifcvf_request_irq(struct ifcvf_adapter *adapter)
> This function was not moved, was it?
>
> Try --minimal or --histogram maybe. Or just
> --anchored=ifcvf_request_irq
Yes, it is not moved, just changed. I tried these parameters,
there are some improvements though seems not significant.
It seems git still finds ifcvf_request_per_vq_irq() uses
some lines of original ifcvf_request_irq().

Thanks for your review and help
Zhu Lingshan
>
>
>> +{
>> +	struct ifcvf_hw *vf = &adapter->vf;
>> +	u16 nvectors, max_intr;
>> +	int ret;
>>   
>> -		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;
>>   }
>>   
>> @@ -436,7 +603,10 @@ 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,
>> -- 
>> 2.27.0

Re: [PATCH V2 0/4] vDPA/ifcvf: implement shared IRQ feature

[Michael S. Tsirkin]

On Tue, Jan 25, 2022 at 05:17:40PM +0800, Zhu Lingshan wrote:
> It has been observed that on some platforms/devices, there may
> not be enough MSI vectors for virtqueues and the config change.
> Under such circumstances, the interrupt sources of a device
> have to share vectors/IRQs.
> 
> This series implemented a shared IRQ feature for ifcvf.

Which configurations did you test with this, and what were
the results? Given patch 3 is broken ...


> Please help review.
> 
> Changes from V1:
> (1) Enable config interrupt when only one vector is allocated(Michael)
> (2) Clean vectors/IRQs if failed to request config interrupt
> since config interrupt is a must(Michael)
> (3) Keep local vdpa_ops, disable irq_bypass by setting IRQ = -EINVAL
> for shared IRQ case(Michael)
> (4) Improvements on error messages(Michael)
> (5) Squash functions implementation patches to the callers(Michael)
> 
> Zhu Lingshan (4):
>   vDPA/ifcvf: implement IO read/write helpers in the header file
>   vDPA/ifcvf: implement device MSIX vector allocator
>   vhost_vdpa: don't setup irq offloading when irq_num < 0
>   vDPA/ifcvf: implement shared IRQ feature
> 
>  drivers/vdpa/ifcvf/ifcvf_base.c |  67 +++------
>  drivers/vdpa/ifcvf/ifcvf_base.h |  60 +++++++-
>  drivers/vdpa/ifcvf/ifcvf_main.c | 254 ++++++++++++++++++++++++++++----
>  drivers/vhost/vdpa.c            |   3 +
>  4 files changed, 305 insertions(+), 79 deletions(-)
> 
> -- 
> 2.27.0