Re: [PATCH v2 1/3] virt: acrn: Introduce interfaces for MMIO device passthrough

[Li Fei1]

On Wed, Aug 25, 2021 at 10:43:29PM +0200, Greg KH wrote:
> On Wed, Aug 25, 2021 at 05:01:40PM +0800, Fei Li wrote:
> > From: Shuo Liu <shuo.a.liu@xxxxxxxxx>
> > 
> > MMIO device passthrough enables an OS in a virtual machine to directly
> > access a MMIO device in the host. It promises almost the native
> > performance, which is required in performance-critical scenarios of
> > ACRN.
> > 
> > HSM provides the following ioctls:
> >   - Assign - ACRN_IOCTL_ASSIGN_MMIODEV
> >     Pass data struct acrn_mmiodev from userspace to the hypervisor, and
> >     inform the hypervisor to assign a MMIO device to a User VM.
> > 
> >   - De-assign - ACRN_IOCTL_DEASSIGN_PCIDEV
> >     Pass data struct acrn_mmiodev from userspace to the hypervisor, and
> >     inform the hypervisor to de-assign a MMIO device from a User VM.
> > 
> > Signed-off-by: Shuo Liu <shuo.a.liu@xxxxxxxxx>
> > Signed-off-by: Fei Li <fei1.li@xxxxxxxxx>
> 
> Where is the userspace code that uses this new api?

Hi Greg

An ACRN userspace application (like QEMU) would uses these new apis in
https://github.com/projectacrn/acrn-hypervisor/blob/master/devicemodel/core/vmmapi.c#L562
and
https://github.com/projectacrn/acrn-hypervisor/blob/master/devicemodel/core/vmmapi.c#L568

thanks.

> 
> thanks,
> 
> greg k-h