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RE: [Xen-devel] [VTD][PATCH] Fix ISA IRQ alias issue

To: "Keir Fraser" <Keir.Fraser@xxxxxxxxxxxx>, <xen-devel@xxxxxxxxxxxxxxxxxxx>
Subject: RE: [Xen-devel] [VTD][PATCH] Fix ISA IRQ alias issue
From: "Han, Weidong" <weidong.han@xxxxxxxxx>
Date: Fri, 23 Nov 2007 23:49:32 +0800
Cc: "Tian, Kevin" <kevin.tian@xxxxxxxxx>, "Kay, Allen M" <allen.m.kay@xxxxxxxxx>
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Thread-topic: [Xen-devel] [VTD][PATCH] Fix ISA IRQ alias issue
Keir,

I still use link_mask field, but rename it as link_map. I think it's a
easy way to record mapped Links, therefore record mapped ISA IRQs in
hvm_set_pci_link_route(). Except this, I adopt all of your other
suggestions. New patch is attached. Thanks!

-- Weidong (Randy)

Keir Fraser wrote:
> hvm_set_pci_link_route dereferences hvm_irq->dpci without checking
> for NULL. 
> 
> hvm_dpci_eoi tests guest_gsi in isairq_mask without checking <
> NR_ISAIRQS. 
> 
> hvm_dpci_isairq_eoi can be a private vt-d function. All external
> callers can continue to go through hvm_dpci_eoi.
> 
> link_mask doesn't look like a very useful field. Get rid of it?
> 
> isairq_mask isn't a great name. It's purpose is quite different from
> dirq_mask for example. Can we come up with a better name for either
> of these fields?
> 
>  -- Keir
> 
> On 17/11/07 05:15, "Han, Weidong" <weidong.han@xxxxxxxxx> wrote:
> 
>> Keir, attached patch adds ISA IRQ handling for EOI of ISA IRQs via
>> IO-APIC, does it eliminate your concern?
>> 
>> -- Weidong
>> 
>> Keir Fraser wrote:
>>> So what if a PCI-ISA IRQ is delivered via, and EOIed via, the
>>> IO-APIC? 
>>> 
>>>  -- Keir
>>> 
>>> On 17/11/07 01:37, "Han, Weidong" <weidong.han@xxxxxxxxx> wrote:
>>> 
>>>> This patch doesn't change EOI of PCI-ISA IRQs via IO-APIC, it just
>>>> uses a separate function to handle EOI of PCI-ISA IRQs via the PIC.
>>>> Without this patch, assigning multiple devices to guest which uses
>>>> PIC maybe results in disabling the IRQ.
>>>> 
>>>> -- Weidong
>>>> 
>>>> Keir Fraser wrote:
>>>>> A concerning amount of code churn and I'm not clear it works for
>>>>> EOI of PCI-ISA IRQs via the IO-APIC. This probably isn't for
>>>>> 3.2.0. 
>>>>> 
>>>>>  -- Keir
>>>>> 
>>>>> On 15/11/07 06:32, "Han, Weidong" <weidong.han@xxxxxxxxx> wrote:
>>>>> 
>>>>>> When assign multiple devices to guest which uses PIC, ISA IRQ
>>>>>> alias may occur. This patch splits ISA IRQ and GSI eoi function.
>>>>>> In ISA IRQ eoi function, searches all assigned mirqs and does
>>>>>> eoi for the corresponding mirqs which match the eoi ISA IRQ.
>>>>>> Therefore fix ISA IRQ alias issue. 
>>>>>> 
>>>>>> 
>>>>>> Signed-off-by: Weidong Han <weidong.han@xxxxxxxxx>
>>>>>> _______________________________________________
>>>>>> Xen-devel mailing list
>>>>>> Xen-devel@xxxxxxxxxxxxxxxxxxx
>>>>>> http://lists.xensource.com/xen-devel
>>>>> 
>>>>> 
>>>>> 
>>>>> _______________________________________________
>>>>> Xen-devel mailing list
>>>>> Xen-devel@xxxxxxxxxxxxxxxxxxx
>>>>> http://lists.xensource.com/xen-devel
>> 
> 
> 
> 
> _______________________________________________
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Attachment: isapic-3.patch
Description: isapic-3.patch

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