Re: [PATCH 6/6] KVM: assigned dev: MSI-X mask support

["Michael S. Tsirkin" <mst@redhat.com>]

On Thu, Nov 18, 2010 at 09:58:55AM +0800, Sheng Yang wrote:
> > > +static int msix_mmio_write(struct kvm_io_device *this, gpa_t addr, int
> > > len, +			   const void *val)
> > > +{
> > > +	struct kvm_assigned_dev_kernel *adev =
> > > +			container_of(this, struct kvm_assigned_dev_kernel,
> > > +				     msix_mmio_dev);
> > > +	int idx, r = 0;
> > > +	unsigned long new_val = *(unsigned long *)val;
> > 
> > What if it's a 64-bit write on a 32-bit host?
> 
> In fact we haven't support QWORD(64bit) accessing now. The reason is we haven't 
> seen any OS is using it in this way now, so I think we can leave it later.
> 
> Also seems QEmu doesn't got the way to handle 64bit MMIO.

I think it does.  I think it simply splits these to 32-bit transactions
and handles as such. That seems to be spec-compilant.  I wouldn't want us
to regress.

-- 
MST