Re: [PATCH 1/3] KVM: Add MSI_ACTION flag for assigned irq

[Sheng Yang <sheng@linux.intel.com>]

On Tuesday 30 December 2008 18:31:16 Avi Kivity wrote:
> Sheng Yang wrote:
> > On Tuesday 30 December 2008 18:19:29 Avi Kivity wrote:
> >> Sheng Yang wrote:
> >>> For MSI disable feature later.
> >>>
> >>> Notice I changed ABI here, but due to no userspace patch, I think it's
> >>> OK.
> >>
> >> It's not okay, since eventually we will have userspace and it will have
> >> to work with older kernels as well.
> >>
> >> No released kernel has KVM_DEV_IRQ_ASSIGN_ENABLE_MSI, so it's fine,
> >> provided I fold this into the 2.6.29 submission.  However, why do this
> >> at all?  It can only cause confusion.
> >
> > If we have ENABLE_MSI, and DISABLE, and ENABLE_MSIX, and DISABLE, and
> > MASK_MSIX, and UNMASK, every two action are in pairs but we have to use
> > twice bits to store them. So I'd like to use MSI_ACTION approach...
>
> Well, it you have flags without ENABLE_MSI, doesn't it imply DISABLE_MSI?
>
> The structure contains the state we want to reach, not a command we wish
> the kernel to perform.

Yes, that's what I want. But check more than one flags(for MSI-X) to determine 
where to go is not that clear. So I add a flag here to indicate the operation 
type which I think is a little more clear.

-- 
regards
Yang, Sheng