Re: [PATCH] ifcvf/vDPA: ifcvf drives standard virtio pci devices

["Zhu, Lingshan" <lingshan.zhu@intel.com>]

On 5/13/2024 9:38 PM, Michael S. Tsirkin wrote:
> On Tue, May 14, 2024 at 05:27:07AM +0800, Zhu Lingshan wrote:
>> Most of ifcvf code work for standard virtio pci,
>> except for bar4. This commit makes bar4 only effective
>> for Intel products, thereby turning ifcvf into
>> a standard virtio pci driver.
>>
>> Signed-off-by: Zhu Lingshan <lingshan.zhu@intel.com>
>> ---
>>   drivers/vdpa/Kconfig            |  2 +-
>>   drivers/vdpa/ifcvf/ifcvf_base.c | 17 ++++++++++++-----
>>   drivers/vdpa/ifcvf/ifcvf_main.c |  5 ++++-
>>   3 files changed, 17 insertions(+), 7 deletions(-)
>>
>> diff --git a/drivers/vdpa/Kconfig b/drivers/vdpa/Kconfig
>> index 656c1cb541de..dbf09f35bcef 100644
>> --- a/drivers/vdpa/Kconfig
>> +++ b/drivers/vdpa/Kconfig
>> @@ -44,7 +44,7 @@ config VDPA_USER
>>   	  in a userspace program.
>>   
>>   config IFCVF
>> -	tristate "Intel IFC VF vDPA driver"
>> +	tristate "Intel IFC VF and standard virtio-pci vDPA driver"
>>   	depends on PCI_MSI
>>   	help
>>   	  This kernel module can drive Intel IFC VF NIC to offload
>> diff --git a/drivers/vdpa/ifcvf/ifcvf_base.c b/drivers/vdpa/ifcvf/ifcvf_base.c
>> index 472daa588a9d..47bc9b11c678 100644
>> --- a/drivers/vdpa/ifcvf/ifcvf_base.c
>> +++ b/drivers/vdpa/ifcvf/ifcvf_base.c
>> @@ -178,7 +178,8 @@ int ifcvf_init_hw(struct ifcvf_hw *hw, struct pci_dev *pdev)
>>   		hw->vring[i].irq = -EINVAL;
>>   	}
>>   
>> -	hw->lm_cfg = hw->base[IFCVF_LM_BAR];
>> +	if (hw->pdev->subsystem_vendor == PCI_VENDOR_ID_INTEL)
>> +		hw->lm_cfg = hw->base[IFCVF_LM_BAR];
>>   
>>   	IFCVF_DBG(pdev,
>>   		  "PCI capability mapping: common cfg: %p, notify base: %p\n, isr cfg: %p, device cfg: %p, multiplier: %u\n",
>> @@ -330,18 +331,24 @@ u16 ifcvf_get_vq_state(struct ifcvf_hw *hw, u16 qid)
>>   	struct ifcvf_lm_cfg  __iomem *lm_cfg = hw->lm_cfg;
>>   	u16 last_avail_idx;
>>   
>> -	last_avail_idx = vp_ioread16(&lm_cfg->vq_state_region + qid * 2);
>> +	if (lm_cfg) {
>> +		last_avail_idx = vp_ioread16(&lm_cfg->vq_state_region + qid * 2);
>> +		return last_avail_idx;
>> +	}
>>   
>> -	return last_avail_idx;
>> +	return -EOPNOTSUPP;
>>   }
>>   
>>   int ifcvf_set_vq_state(struct ifcvf_hw *hw, u16 qid, u16 num)
>>   {
>>   	struct ifcvf_lm_cfg  __iomem *lm_cfg = hw->lm_cfg;
>>   
>> -	vp_iowrite16(num, &lm_cfg->vq_state_region + qid * 2);
>> +	if (lm_cfg) {
>> +		vp_iowrite16(num, &lm_cfg->vq_state_region + qid * 2);
>> +		return 0;
>> +	}
>>   
>> -	return 0;
>> +	return -EOPNOTSUPP;
>>   }
>>   
>>   void ifcvf_set_vq_num(struct ifcvf_hw *hw, u16 qid, u32 num)
>> diff --git a/drivers/vdpa/ifcvf/ifcvf_main.c b/drivers/vdpa/ifcvf/ifcvf_main.c
>> index 80d0a0460885..e89fd4d96ff1 100644
>> --- a/drivers/vdpa/ifcvf/ifcvf_main.c
>> +++ b/drivers/vdpa/ifcvf/ifcvf_main.c
>> @@ -1,6 +1,7 @@
>>   // SPDX-License-Identifier: GPL-2.0-only
>>   /*
>>    * Intel IFC VF NIC driver for virtio dataplane offloading
>> + * This driver also drives standard virtio-pci hardwares
>>    *
>>    * Copyright (C) 2020 Intel Corporation.
>>    *
>> @@ -880,7 +881,9 @@ static struct pci_device_id ifcvf_pci_ids[] = {
>>   			 VIRTIO_TRANS_ID_BLOCK,
>>   			 PCI_VENDOR_ID_INTEL,
>>   			 VIRTIO_ID_BLOCK) },
>> -
>> +	/* standard virtio pci devices */
>> +	{ PCI_DEVICE(PCI_VENDOR_ID_REDHAT_QUMRANET,
>> +		     PCI_ANY_ID) },
>>   	{ 0 },
>>   };
>>   MODULE_DEVICE_TABLE(pci, ifcvf_pci_ids);
> Will make it conflict with the normal virtio driver, won't it?
>
> What are you trying to achieve here?
The confliction exists before, in my setup, virtio-pci driver always 
probe virtio-pci devices
before ifcvf.

Since ifcvf drives is all standard virtio-pci except for bar4, so this 
patch intends to maximize
the use of the ifcvf driver and allow developers without Intel hardware 
to also develop this driver.

Thanks
Zhu Lingshan
>
>
>
>> -- 
>> 2.43.0