Message-ID: <55BB2379.8070809@linaro.org>
Date: Fri, 31 Jul 2015 09:27:53 +0200
From: Eric Auger <eric.auger@linaro.org>
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To: David Gibson <david@gibson.dropbear.id.au>, alex.williamson@redhat.com,
        pbonzini@redhat.com
CC: paulus@samba.org, aik@ozlabs.ru, mdroth@linux.vnet.ibm.com,
        benh@kernel.crashing.org, mpe@ellerman.id.au, kvm@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH] vfio: Enable VFIO device for powerpc
References: <1437372731-11097-1-git-send-email-david@gibson.dropbear.id.au>
In-Reply-To: <1437372731-11097-1-git-send-email-david@gibson.dropbear.id.au>
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Hi David,

As noticed we did the same on ARM (4.2) for the same reason.
Reviewed-by: Eric Auger <eric.auger@linaro.org>

Best Regards

Eric


On 07/20/2015 08:12 AM, David Gibson wrote:
> ec53500f "kvm: Add VFIO device" added a special KVM pseudo-device which is
> used to handle any necessary interactions between KVM and VFIO.
> 
> Currently that device is built on x86 and ARM, but not powerpc, although
> powerpc does support both KVM and VFIO.  This makes things awkward in
> userspace
> 
> Currently qemu prints an alarming error message if you attempt to use VFIO
> and it can't initialize the KVM VFIO device.  We don't want to remove the
> warning, because lack of the KVM VFIO device could mean coherency problems
> on x86.  On powerpc, however, the error is harmless but looks disturbing,
> and a test based on host architecture in qemu would be ugly, and break if
> we do need the KVM VFIO device for something important in future.
> 
> There's nothing preventing the KVM VFIO device from being built for
> powerpc, so this patch turns it on.  It won't actually do anything, since
> we don't define any of the arch_*() hooks, but it will make qemu happy and
> we can extend it in future if we need to.
> 
> Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
> ---
>  arch/powerpc/kvm/Makefile | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/powerpc/kvm/Makefile b/arch/powerpc/kvm/Makefile
> index 0570eef..7f7b6d8 100644
> --- a/arch/powerpc/kvm/Makefile
> +++ b/arch/powerpc/kvm/Makefile
> @@ -8,7 +8,7 @@ ccflags-y := -Ivirt/kvm -Iarch/powerpc/kvm
>  KVM := ../../../virt/kvm
>  
>  common-objs-y = $(KVM)/kvm_main.o $(KVM)/coalesced_mmio.o \
> -		$(KVM)/eventfd.o
> +		$(KVM)/eventfd.o $(KVM)/vfio.o
>  
>  CFLAGS_e500_mmu.o := -I.
>  CFLAGS_e500_mmu_host.o := -I.
> 

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