Re: [PATCH v4 6/6] xen/vpci: header: filter PCI capabilities

[Stewart Hildebrand <stewart.hildebrand@xxxxxxx>]

On 8/28/23 13:56, Stewart Hildebrand wrote:
> diff --git a/xen/drivers/vpci/header.c b/xen/drivers/vpci/header.c
> index 4a4dbb69ab1c..919addbfa630 100644
> --- a/xen/drivers/vpci/header.c
> +++ b/xen/drivers/vpci/header.c
> @@ -561,6 +573,71 @@ static int cf_check init_bars(struct pci_dev *pdev)
>      if ( rc )
>          return rc;
>  
> +    if ( !is_hardware_domain(pdev->domain) )
> +    {
> +        if ( !(pci_conf_read16(pdev->sbdf, PCI_STATUS) & 
> PCI_STATUS_CAP_LIST) )
> +        {
> +            /* RAZ/WI */
> +            rc = vpci_add_register(pdev->vpci, vpci_read_val, NULL,
> +                                   PCI_CAPABILITY_LIST, 1, (void *)0);
> +            if ( rc )
> +                return rc;
> +        }
> +        else
> +        {
> +            /* Only expose capabilities to the guest that vPCI can handle. */
> +            uint8_t next;

s/uint8_t/unsigned int/

> +            unsigned int ttl = 48;
> +
> +            next = pci_find_next_cap_ttl(pdev->sbdf, PCI_CAPABILITY_LIST,
> +                                         vpci_cap_supported, 0, &ttl);
> +
> +            rc = vpci_add_register(pdev->vpci, vpci_read_val, NULL,
> +                                   PCI_CAPABILITY_LIST, 1,
> +                                   (void *)(uintptr_t)next);
> +            if ( rc )
> +                return rc;
> +
> +            next &= ~3;
> +
> +            if ( !next )
> +                /*
> +                 * If we don't have any supported capabilities to expose to 
> the
> +                 * guest, mask the PCI_STATUS_CAP_LIST bit in the status
> +                 * register.
> +                 */
> +                header->mask_cap_list = true;
> +
> +            while ( next && ttl )
> +            {
> +                uint8_t pos = next;

s/uint8_t/unsigned int/