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

[DuanZhenzhong <zhenzhong.duan@oracle.com>]

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@oracle.com> 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@google.com>
>>>> CC: Sucheta Chakraborty <sucheta.chakraborty@qlogic.com>
>>>> CC: Zhenzhong Duan <zhenzhong.duan@oracle.com>
>>>> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
>>>>         
>>> 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
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