Re: [Xen-devel] [PATCH 0/6] MSI-INTx interrupt translation for HVM

[Shohei Fujiwara <fujiwara-sxa@xxxxxxxxxxxxxxx>]

I have one question.

MSI interrupt is edge-triggered, and INTx interrupt is level-triggered.
Guest OS handles translated interrupt as level-triggered, though physical
interrupt is edge-triggered. When two interrupts are raised during short
period, Guest OS might lose 2nd interrupt, I think.

What do you think?

Thanks,
--
Shohei Fujiwara

On Thu,  8 Jan 2009 17:06:43 +0800
Qing He <qing.he@xxxxxxxxx> wrote:

> This patchset enables MSI-INTx interrupt translation for HVM
> domains. The intention of the patch is to use MSI as the physical
> interrupt mechanism for passthrough device as much as possible,
> thus reducing the pirq sharing among domains.
> 
> When MSI is globally enabled, if the device has the MSI capability
> but doesn't used by the guest, hypervisor will try to user MSI as
> the underlying pirq and inject translated INTx irq to guest
> vioapic. When guest itself enabled MSI or MSI-X, the translation
> is automatically turned off.
> 
> Add a config file option to disable/enable this feature. Also, in
> order to allow the user to override the option per device, a
> per-device option mechanism is implemented and an MSI-INTx option
> is added
> 
> The patch set contains 6 patches and is organized as below:
>     [PATCH 1/6] hypervisor patch
>    *[PATCH 2/6] qemu patch
>     [PATCH 3/6] add pci options in domain config file
>     [PATCH 4/6] XenAPI version of the above patch
>     [PATCH 5/6] add global and per-device option for MSI-INTx
>     [PATCH 6/6] documentation and example
> 
>  * against ioemu-remote
> 
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> Xen-devel@xxxxxxxxxxxxxxxxxxx
> http://lists.xensource.com/xen-devel


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