Re: [Qemu-devel] [PATCH qemu] vfio_pci: Allow disabling quirks

[Alex Williamson <alex.williamson@redhat.com>]

On Sun, 2015-07-19 at 18:19 +1000, Alexey Kardashevskiy wrote:
> The existing quirks aim config space and MSIX BAR accesses interception.
> These are not always needed, for example, on pseries machines,
> config space and MSI/MSIX configuration are handled by hypervisor.
> 
> This adds a "quirks" property to control whether to enable quirks or not;
> the property is set to "true" by default.
> 
> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
> ---
> 
> Helps to get
> VGA compatible controller: NVIDIA Corporation GM107GL [Quadro K2200] (rev a2)
> (which does not need the quirk anyway) working on POWER8 system.
> ---
>  hw/vfio/pci.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
> index 2ed877f..ba47301 100644
> --- a/hw/vfio/pci.c
> +++ b/hw/vfio/pci.c
> @@ -168,6 +168,7 @@ typedef struct VFIOPCIDevice {
>      bool has_flr;
>      bool has_pm_reset;
>      bool rom_read_failed;
> +    bool allow_quirks;
>  } VFIOPCIDevice;
>  
>  typedef struct VFIORomBlacklistEntry {
> @@ -2442,7 +2443,9 @@ static void vfio_map_bar(VFIOPCIDevice *vdev, int nr)
>          }
>      }
>  
> -    vfio_bar_quirk_setup(vdev, nr);
> +    if (vdev->allow_quirks) {
> +        vfio_bar_quirk_setup(vdev, nr);
> +    }
>  }
>  
>  static void vfio_map_bars(VFIOPCIDevice *vdev)
> @@ -3753,6 +3756,7 @@ static Property vfio_pci_dev_properties[] = {
>                      VFIO_FEATURE_ENABLE_REQ_BIT, true),
>      DEFINE_PROP_INT32("bootindex", VFIOPCIDevice, bootindex, -1),
>      DEFINE_PROP_BOOL("x-mmap", VFIOPCIDevice, vbasedev.allow_mmap, true),
> +    DEFINE_PROP_BOOL("quirks", VFIOPCIDevice, allow_quirks, true),
>      /*
>       * TODO - support passed fds... is this necessary?
>       * DEFINE_PROP_STRING("vfiofd", VFIOPCIDevice, vfiofd_name),


NAK, if you don't need it for power then make it automatically disabled
for power.  Otherwise you're just pushing the burden onto the
user/libvirt to know when to use this option.  Thanks,

Alex