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Re: [Qemu-devel] [RFC][patch 3/6] KVM: s390: Add GISA support
From: |
Frank Blaschka |
Subject: |
Re: [Qemu-devel] [RFC][patch 3/6] KVM: s390: Add GISA support |
Date: |
Fri, 5 Sep 2014 12:52:33 +0200 |
User-agent: |
Mutt/1.5.17 (2007-11-01) |
On Fri, Sep 05, 2014 at 10:29:26AM +0200, Alexander Graf wrote:
>
>
> On 04.09.14 12:52, address@hidden wrote:
> > From: Frank Blaschka <address@hidden>
> >
> > This patch adds GISA (Guest Interrupt State Area) support
> > to s390 kvm. GISA can be used for exitless interrupts. The
> > patch provides a set of functions for GISA related operations
> > like accessing GISA fields or registering ISCs for alert.
> > Exploiters of GISA will follow with additional patches.
> >
> > Signed-off-by: Frank Blaschka <address@hidden>
>
> That's a nice feature. However, please make sure that you maintain the
> abstraction levels.
>
> What should happen is that you request an irqfd from FLIC. Then you
> associate that irqfd with the PCI device.
>
> Thanks to that association, both parties can now talk to each other and
> negotiate their GISA number space and make sure things are connected.
>
> However, it should always be possible to do things without this direct
> IRQ injection.
>
> So you should be able to receive an irqfd event when an IRQ happened, so
> that VFIO user space applications can also handle interrupts for example.
>
> And the same applies for interrupt injection. We also need to be able to
> inject an adapter interrupt from QEMU for emulated devices ;).
>
OK, assuming we are doing the vfio solution expoiting GISA would be a
second step. Will take your feedback into account. THX!
>
> Alex
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- Re: [Qemu-devel] [RFC][patch 0/6] pci pass-through support for qemu/KVM on s390, (continued)
[Qemu-devel] [RFC][patch 1/6] s390: cio: chsc function to register GIB, frank . blaschka, 2014/09/04
[Qemu-devel] [RFC][patch 4/6] KVM: s390: Add PCI pass-through support, frank . blaschka, 2014/09/04
[Qemu-devel] [RFC][patch 2/6] s390: pci: export pci functions for pass-through usage, frank . blaschka, 2014/09/04
[Qemu-devel] [RFC][patch 3/6] KVM: s390: Add GISA support, frank . blaschka, 2014/09/04
[Qemu-devel] [RFC][patch 6/6] s390: Add PCI pass-through device support, frank . blaschka, 2014/09/04
[Qemu-devel] [RFC][patch 5/6] s390: Add PCI bus support, frank . blaschka, 2014/09/04
Re: [Qemu-devel] [RFC][patch 0/6] pci pass-through support for qemu/KVM on s390, Alexander Graf, 2014/09/05