Re: [Xen-devel] [PATCH v2 2/2] x86/io: move the list of guest to machine IO ports out of domain_iommu

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 04.04.17 at 13:06, <roger.pau@xxxxxxxxxx> wrote:
> On Wed, Mar 29, 2017 at 11:49:53AM +0100, Roger Pau Monne wrote:
>> On Wed, Mar 29, 2017 at 11:41:40AM +0100, Andrew Cooper wrote:
>> > On 28/03/17 14:12, Roger Pau Monne wrote:
>> > > There's no reason to store that list inside of the domain_iommu struct, 
>> > > the
>> > > forwarding of guest IO ports into machine IO ports is not tied to the 
>> > > presence
>> > > of an IOMMU.
>> > >
>> > > Move it inside of the hvm_domain struct instead.
>> > >
>> > > Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
>> > 
>> > Actually, on second thoughts, I rescind my R-by.
>> > 
>> > This breaks PV guests, which must not use state in the hvm half of the
>> > union.
>> 
>> I'm extremely confused now, AFAICT the g2m_ioport_list list is only used by 
>> the
>> g2m_portio_* handlers, and those handlers already make use of HVM only fields
>> (ie: hvm_vcpu_io).
> 
> Can this be committed?

As said on irc, I think was posted after the last posting date, so you'd
need to obtain an ack from Julien.

> I understand there's a previous regression here, but
> this patches don't make it any worse AFAICT, and they clarify the 
> nomenclature.

I don't see the "previous regression": The handlers can be invoked
only for HVM guests. What is not HVM-specific is the domctl, and
there is where you introduce a regression.

Jan

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