Re: [PATCH v4] PCI: vmd: Offset Client VMD MSI-X vectors

["Derrick, Jonathan" <jonathan.derrick@intel.com>]

Hi Lorenzo

Please don't forget this one

Thanks

On Mon, 2020-11-02 at 15:22 -0700, Jon Derrick wrote:
> Client VMD platforms have a software-triggered MSI-X vector 0 that will
> not forward hardware-remapped MSI from the sub-device domain. This
> causes an issue with VMD platforms that use AHCI behind VMD and have a
> single MSI-X vector remapped to VMD vector 0. Add a VMD MSI-X vector
> offset for these platforms.
> 
> Signed-off-by: Jon Derrick <jonathan.derrick@intel.com>
> Tested-by: Jian-Hong Pan <jhp@endlessos.org>
> ---
> v3->v4: Rebase for v5.10
> 
> drivers/pci/controller/vmd.c | 37 +++++++++++++++++++++++++-----------
>  1 file changed, 26 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/pci/controller/vmd.c b/drivers/pci/controller/vmd.c
> index f375c21ceeb1..c31e4d5cb146 100644
> --- a/drivers/pci/controller/vmd.c
> +++ b/drivers/pci/controller/vmd.c
> @@ -53,6 +53,12 @@ enum vmd_features {
>  	 * vendor-specific capability space
>  	 */
>  	VMD_FEAT_HAS_MEMBAR_SHADOW_VSCAP	= (1 << 2),
> +
> +	/*
> +	 * Device may use MSI-X vector 0 for software triggering and will not
> +	 * be used for MSI remapping
> +	 */
> +	VMD_FEAT_OFFSET_FIRST_VECTOR		= (1 << 3),
>  };
>  
>  /*
> @@ -104,6 +110,7 @@ struct vmd_dev {
>  	struct irq_domain	*irq_domain;
>  	struct pci_bus		*bus;
>  	u8			busn_start;
> +	u8			first_vec;
>  };
>  
>  static inline struct vmd_dev *vmd_from_bus(struct pci_bus *bus)
> @@ -199,11 +206,11 @@ static irq_hw_number_t vmd_get_hwirq(struct msi_domain_info *info,
>   */
>  static struct vmd_irq_list *vmd_next_irq(struct vmd_dev *vmd, struct msi_desc *desc)
>  {
> -	int i, best = 1;
>  	unsigned long flags;
> +	int i, best;
>  
> -	if (vmd->msix_count == 1)
> -		return &vmd->irqs[0];
> +	if (vmd->msix_count == 1 + vmd->first_vec)
> +		return &vmd->irqs[vmd->first_vec];
>  
>  	/*
>  	 * White list for fast-interrupt handlers. All others will share the
> @@ -213,11 +220,12 @@ static struct vmd_irq_list *vmd_next_irq(struct vmd_dev *vmd, struct msi_desc *d
>  	case PCI_CLASS_STORAGE_EXPRESS:
>  		break;
>  	default:
> -		return &vmd->irqs[0];
> +		return &vmd->irqs[vmd->first_vec];
>  	}
>  
>  	raw_spin_lock_irqsave(&list_lock, flags);
> -	for (i = 1; i < vmd->msix_count; i++)
> +	best = vmd->first_vec + 1;
> +	for (i = best; i < vmd->msix_count; i++)
>  		if (vmd->irqs[i].count < vmd->irqs[best].count)
>  			best = i;
>  	vmd->irqs[best].count++;
> @@ -550,8 +558,8 @@ static int vmd_alloc_irqs(struct vmd_dev *vmd)
>  	if (vmd->msix_count < 0)
>  		return -ENODEV;
>  
> -	vmd->msix_count = pci_alloc_irq_vectors(dev, 1, vmd->msix_count,
> -						PCI_IRQ_MSIX);
> +	vmd->msix_count = pci_alloc_irq_vectors(dev, vmd->first_vec + 1,
> +						vmd->msix_count, PCI_IRQ_MSIX);
>  	if (vmd->msix_count < 0)
>  		return vmd->msix_count;
>  
> @@ -719,6 +727,7 @@ static int vmd_enable_domain(struct vmd_dev *vmd, unsigned long features)
>  
>  static int vmd_probe(struct pci_dev *dev, const struct pci_device_id *id)
>  {
> +	unsigned long features = (unsigned long) id->driver_data;
>  	struct vmd_dev *vmd;
>  	int err;
>  
> @@ -743,13 +752,16 @@ static int vmd_probe(struct pci_dev *dev, const struct pci_device_id *id)
>  	    dma_set_mask_and_coherent(&dev->dev, DMA_BIT_MASK(32)))
>  		return -ENODEV;
>  
> +	if (features & VMD_FEAT_OFFSET_FIRST_VECTOR)
> +		vmd->first_vec = 1;
> +
>  	err = vmd_alloc_irqs(vmd);
>  	if (err)
>  		return err;
>  
>  	spin_lock_init(&vmd->cfg_lock);
>  	pci_set_drvdata(dev, vmd);
> -	err = vmd_enable_domain(vmd, (unsigned long) id->driver_data);
> +	err = vmd_enable_domain(vmd, features);
>  	if (err)
>  		return err;
>  
> @@ -818,13 +830,16 @@ static const struct pci_device_id vmd_ids[] = {
>  				VMD_FEAT_HAS_BUS_RESTRICTIONS,},
>  	{PCI_DEVICE(PCI_VENDOR_ID_INTEL, 0x467f),
>  		.driver_data = VMD_FEAT_HAS_MEMBAR_SHADOW_VSCAP |
> -				VMD_FEAT_HAS_BUS_RESTRICTIONS,},
> +				VMD_FEAT_HAS_BUS_RESTRICTIONS |
> +				VMD_FEAT_OFFSET_FIRST_VECTOR,},
>  	{PCI_DEVICE(PCI_VENDOR_ID_INTEL, 0x4c3d),
>  		.driver_data = VMD_FEAT_HAS_MEMBAR_SHADOW_VSCAP |
> -				VMD_FEAT_HAS_BUS_RESTRICTIONS,},
> +				VMD_FEAT_HAS_BUS_RESTRICTIONS |
> +				VMD_FEAT_OFFSET_FIRST_VECTOR,},
>  	{PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_VMD_9A0B),
>  		.driver_data = VMD_FEAT_HAS_MEMBAR_SHADOW_VSCAP |
> -				VMD_FEAT_HAS_BUS_RESTRICTIONS,},
> +				VMD_FEAT_HAS_BUS_RESTRICTIONS |
> +				VMD_FEAT_OFFSET_FIRST_VECTOR,},
>  	{0,}
>  };
>  MODULE_DEVICE_TABLE(pci, vmd_ids);