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From: Sasha Levin <levinsasha928@gmail.com>
To: Matt Evans <matt@ozlabs.org>
Cc: kvm@vger.kernel.org, kvm-ppc@vger.kernel.org, penberg@kernel.org,
	asias.hejun@gmail.com, gorcunov@gmail.com,
	Alexander Graf <agraf@suse.de>
Subject: Re: [PATCH V2 0/2] kvm tools: PPC64 basic support
Date: Wed, 14 Dec 2011 08:35:55 +0200	[thread overview]
Message-ID: <1323844555.3992.13.camel@lappy> (raw)
In-Reply-To: <4EE7EEF8.9090804@ozlabs.org>

On Wed, 2011-12-14 at 11:34 +1100, Matt Evans wrote:
> On 13/12/11 21:23, Sasha Levin wrote:
> > On Tue, 2011-12-13 at 18:00 +1100, Matt Evans wrote:
> >> The second patch is a small fix for generic virtio code (now that we have a
> >> PPC build) which removes reliance on ioeventfds for PPC, which doesn't provide
> >> them. 
> > 
> > Hm... ioeventfds are located in the generic code and should be available
> > on all archs (it doesn't use any arch specific code at all afaik).
> > 
> > Why don't they work on ppc?
> > 
> 
> Well, there are two problems: you're right that it's generic code, but it's
> configurable and CONFIG_HAVE_KVM_EVENTFD isn't set for PPC KVM (thus the ioctl
> fails).  That's probably off because ioevents won't work anyway-- the in-kernel
> MMIO exit route isn't wired up to kvm_io_bus_read/write() yet.  (It looks like
> KVM_IRQFD will also fail, which virtio-pci /would/ use if I supported MSIs,
> which I currently don't.)
> 
> Yes, this can be fixed, but relying on it means that virtio on kvmtool/PPC won't
> work on today's kernels. :(

In that case, KVM_CAP_IOEVENTFD is simply not set, so we're better off
checking the cap dynamically instead of having it defined statically in
the makefile.

I'll send a short patch that does that.

-- 

Sasha.


  reply	other threads:[~2011-12-14  6:36 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-12-13  7:00 [PATCH V2 0/2] kvm tools: PPC64 basic support Matt Evans
2011-12-13  7:00 ` [PATCH V2 1/2] kvm tools: Add initial SPAPR PPC64 architecture support Matt Evans
2011-12-13  7:44   ` Pekka Enberg
2011-12-14  9:38     ` Benjamin Herrenschmidt
2011-12-14 10:30       ` Pekka Enberg
2011-12-14 10:41         ` Benjamin Herrenschmidt
     [not found]           ` <521B67B5-FA19-479A-A1DF-14A0E65C30AF@suse.de>
2011-12-14 11:31             ` Pekka Enberg
2011-12-14 13:36             ` Asias He
2011-12-13  8:23   ` Alexander Graf
2011-12-15  1:27     ` Matt Evans
2011-12-15  1:37       ` Alexander Graf
2011-12-15  2:20         ` Matt Evans
2011-12-13 17:43   ` Pekka Enberg
2011-12-13 21:41     ` Matt Evans
2011-12-13  7:00 ` [PATCH V2 2/2] kvm tools: Make virtio-pci's ioeventfd__add_event() fall back gracefully if ioeventfds unavailable Matt Evans
2011-12-13 10:23 ` [PATCH V2 0/2] kvm tools: PPC64 basic support Sasha Levin
2011-12-14  0:34   ` Matt Evans
2011-12-14  6:35     ` Sasha Levin [this message]
2011-12-14  9:35       ` Benjamin Herrenschmidt

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