Re: [Qemu-devel] [PATCH 1/2] KVM: page track: add a new notifier type: track_flush_slot

[Paolo Bonzini]

On 14/10/2016 12:37, Jike Song wrote:
> Hi Paolo & Alex,
> 
> IIUC, passing file descriptors means touching QEMU and the UAPI between
> QEMU and VFIO. Would you guys have a look at below draft patch? If it's
> on the correct direction, I'll send the split ones. Thanks!
> 
> --
> Thanks,
> Jike
> 
> 
> diff --git a/hw/vfio/pci-quirks.c b/hw/vfio/pci-quirks.c
> index bec694c..f715d37 100644
> --- a/hw/vfio/pci-quirks.c
> +++ b/hw/vfio/pci-quirks.c
> @@ -10,12 +10,14 @@
>   * the COPYING file in the top-level directory.
>   */
>  
> +#include <sys/ioctl.h>
>  #include "qemu/osdep.h"
>  #include "qemu/error-report.h"
>  #include "qemu/range.h"
>  #include "qapi/error.h"
>  #include "hw/nvram/fw_cfg.h"
>  #include "pci.h"
> +#include "sysemu/kvm.h"
>  #include "trace.h"
>  
>  /* Use uin32_t for vendor & device so PCI_ANY_ID expands and cannot match hw 
> */
> @@ -1844,3 +1846,15 @@ void vfio_setup_resetfn_quirk(VFIOPCIDevice *vdev)
>          break;
>      }
>  }
> +
> +void vfio_quirk_kvmgt(VFIOPCIDevice *vdev)
> +{
> +    int vmfd;
> +
> +    if (!kvm_enabled() || !vdev->kvmgt)
> +        return;
> +
> +    /* Tell the device what KVM it attached */
> +    vmfd = kvm_get_vmfd(kvm_state);
> +    ioctl(vdev->vbasedev.fd, VFIO_SET_KVMFD, vmfd);
> +}

vfio_kvm_device_add_group is already telling the group id file
descriptor to KVM.  You can use that existing hook (whose kernel side is
virt/kvm/vfio.c).

Paolo