Re: [Xen-devel] [PATCH] PCI: Introduce two new MSI infrastructure calls for masking/unmasking.

[DuanZhenzhong <zhenzhong.duan@xxxxxxxxxx>]

Konrad Rzeszutek Wilk wrote:
> On Fri, Nov 08, 2013 at 09:44:09AM +0800, Zhenzhong Duan wrote:
>   
> > On 2013-11-07 07:51, Bjorn Helgaas wrote:
> >     
> > > [+cc Thomas, Ingo, Peter, x86 list]
> > >
> > > On Wed, Nov 6, 2013 at 2:16 PM, Konrad Rzeszutek Wilk
> > > <konrad.wilk@xxxxxxxxxx> wrote:
> > >       
> > > > Certain platforms do not allow writes in the MSI-X bars
> > > > to setup or tear down vector values. To combat against
> > > > the generic code trying to write to that and either silently
> > > > being ignored or crashing due to the pagetables being marked r/o
> > > > this patch introduces a platform over-write.
> > > >
> > > > Note that we keep two separate, non-weak, functions
> > > > default_mask_msi_irqs() and default_mask_msix_irqs() for the
> > > > behavior of the arch_mask_msi_irqs() and arch_mask_msix_irqs(),
> > > > as the default behavior is needed by x86 PCI code.
> > > >
> > > > For Xen, which does not allow the guest to write to MSI-X
> > > > tables - as the hypervisor is solely responsible for setting
> > > > the vector values - we implement two nops.
> > > >
> > > > CC: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
> > > > CC: Sucheta Chakraborty <sucheta.chakraborty@xxxxxxxxxx>
> > > > CC: Zhenzhong Duan <zhenzhong.duan@xxxxxxxxxx>
> > > > Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
> > > >         
> > > I think this is safe, and I'd like to squeeze it into the v3.13 merge
> > > window next week, since it supersedes three patches Zhenzhong has been
> > > trying to get in since July [1], and this patch is much simpler to
> > > understand.
> > >       
> > This patch could replace the first two.
> > I think the third patch of mine is still needed as it does a
> > different thing.
> > It optimizes restore path in dom0.
> >     
> I tried to rebase it on top of this patch but it ended up that
> you still need the two arguments (for restore_... operation). 
>
> But perhaps there is a better way. If you can rebase on top
> of this patch - and send it out - that would be great!
>   
Ok, I'll send one rebased on your patch later.

--
Regards
zhenzhong
--
Oracle Building, No.24 Building, Zhongguancun Software Park
Haidian District, Beijing 100193, China


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