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Re: [Qemu-devel] [PATCH] RFC kvm irqfd: add directly mapped MSI IRQ supp
From: |
Alexander Graf |
Subject: |
Re: [Qemu-devel] [PATCH] RFC kvm irqfd: add directly mapped MSI IRQ support |
Date: |
Mon, 24 Jun 2013 16:34:45 +0200 |
On 24.06.2013, at 16:31, Anthony Liguori wrote:
> "Michael S. Tsirkin" <address@hidden> writes:
>
>> On Mon, Jun 24, 2013 at 08:34:52AM -0500, Anthony Liguori wrote:
>>> Gleb Natapov <address@hidden> writes:
>>>
>>> Isn't this more or less what Avi's previous proposal was around changing
>>> the APIC interfaces to userspace?
>>>
>>> Regards,
>>>
>>> Anthony Liguori
>>
>> While that's not very elegant, I think we can use the existing
>> interface for this: just encode things in a fake
>> "msi message" in the format that kernel expects.
>
> This is, in fact, exactly what we do today. The MSI interfaces aren't
> for MSI. They are for sending messages to the APIC bus. What we should
> do is:
>
> #define KVM_SIGNAL_LAPIC KVM_SIGNAL_MSI
> #define KVM_IRQ_ROUTING_LAPIC KVM_IRQ_ROUTING_MSI
>
> And switch to using the new #defines in QEMU. That would make it more
> obvious where we need to refactor things. We currently hard code
> routing via a local APIC with MSI. We need to change this into a bus
> specific function that can choose the right interface.
>
> I think Power is fine with just doing all routing through the irqchip
> interface. We may need other routing interfaces for other architectures
> though.
I'm not quite sure what problem exactly you're trying to solve here. The main
user of MSI injects through irqfd are in the kernel and definitely want a fast
path to inject those without any involvement of QEMU at all.
Alex
- Re: [Qemu-devel] [PATCH] RFC kvm irqfd: add directly mapped MSI IRQ support, (continued)
- Re: [Qemu-devel] [PATCH] RFC kvm irqfd: add directly mapped MSI IRQ support, Gleb Natapov, 2013/06/24
- Re: [Qemu-devel] [PATCH] RFC kvm irqfd: add directly mapped MSI IRQ support, Anthony Liguori, 2013/06/24
- Re: [Qemu-devel] [PATCH] RFC kvm irqfd: add directly mapped MSI IRQ support, Alexander Graf, 2013/06/24
- Re: [Qemu-devel] [PATCH] RFC kvm irqfd: add directly mapped MSI IRQ support, Gleb Natapov, 2013/06/24
- Re: [Qemu-devel] [PATCH] RFC kvm irqfd: add directly mapped MSI IRQ support, Anthony Liguori, 2013/06/24
- Re: [Qemu-devel] [PATCH] RFC kvm irqfd: add directly mapped MSI IRQ support, Michael S. Tsirkin, 2013/06/24
- Re: [Qemu-devel] [PATCH] RFC kvm irqfd: add directly mapped MSI IRQ support, Anthony Liguori, 2013/06/24
- Re: [Qemu-devel] [PATCH] RFC kvm irqfd: add directly mapped MSI IRQ support,
Alexander Graf <=
- Re: [Qemu-devel] [PATCH] RFC kvm irqfd: add directly mapped MSI IRQ support, Anthony Liguori, 2013/06/24
- Re: [Qemu-devel] [PATCH] RFC kvm irqfd: add directly mapped MSI IRQ support, Gleb Natapov, 2013/06/24
- Re: [Qemu-devel] [PATCH] RFC kvm irqfd: add directly mapped MSI IRQ support, Gleb Natapov, 2013/06/24