Re: [Xen-devel] [VTD][PATCH] interrupt remapping patch for xen 3.3

[Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>]

Okay, that only made a little sense to me. The main problem I have with
fiddling with io-apic entries is that they're all actually under the
management of dom0 kernel.

 -- Keir

On 24/1/08 22:33, "Kay, Allen M" <allen.m.kay@xxxxxxxxx> wrote:

> Interrupt remapping redirects ioapic/msi interrupt entries to interrupt
> remap table.  SID field in the Interrupt Remapping Table Entry qualifies
> the interrupt with BDF information of the ioapic/MSI devices.
> 
> Therefore the main value it adds for current Xen VT-d/PCI passthru is
> that it protects hypervisor interrupts from malicious attacks from
> guests with passthru devices.  Other benefits it can provide is easier
> IRQ rebalancing and extended APIC ID support.
> 
> Allen
> 
>> -----Original Message-----
>> From: Keir Fraser [mailto:Keir.Fraser@xxxxxxxxxxxx]
>> Sent: Thursday, January 24, 2008 12:14 AM
>> To: Kay, Allen M; xen-devel@xxxxxxxxxxxxxxxxxxx
>> Cc: Han, Weidong
>> Subject: Re: [Xen-devel] [VTD][PATCH] interrupt remapping
>> patch for xen 3.3
>> 
>> What exactly does irq remapping mean, and what are its benefits in the
>> current Xen VT-D architecture? It's really not at all clear
>> what's going on
>> from the current VT-D documentation.
>> 
>> Since all interrupts get abstracted through Xen right now, if
>> it's just an
>> interrupt-line remapping then that doesn't seem very useful...
>> 
>> -- Keir
>> 
>> On 24/1/08 02:33, "Kay, Allen M" <allen.m.kay@xxxxxxxxx> wrote:
>> 
>>> Attached patch remaps interrupt for passthru device if such HW is
>>> detected on VT-d platforms.
>>> 
>>> Signed-off-by: Allen Kay <allen.m.kay@xxxxxxxxx>
>>> _______________________________________________
>>> Xen-devel mailing list
>>> Xen-devel@xxxxxxxxxxxxxxxxxxx
>>> http://lists.xensource.com/xen-devel
>> 
>> 
>> 



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