[PATCH] vfio: Enable VFIO device for powerpc

[PATCH] vfio: Enable VFIO device for powerpc

[David Gibson]

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.
-- 
2.4.3

Re: [PATCH] vfio: Enable VFIO device for powerpc

[Eric Auger]

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.
> 

[PATCH] vfio: Enable VFIO device for powerpc

[David Gibson]

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>
Reviewed-by: Eric Auger <eric.auger@linaro.org>
---
 arch/powerpc/kvm/Makefile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Alex (Graf), sorry, forgot to send this to you on my first posting of
this patch, but I'm guessing it's your tree it should go in via.
Resending, with Eric's reviewed-by line folded in.  Please apply.

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.
-- 
2.4.3

Re: [PATCH] vfio: Enable VFIO device for powerpc

[Alexander Graf]

On 13.08.15 03:15, 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>
> Reviewed-by: Eric Auger <eric.auger@linaro.org>

Paul is going to take care of the kvm-ppc tree for 4.3. Also, ppc kvm
patches should get CC on the kvm-ppc@vger mailing list ;).

Paul, could you please pick this one up?


Thanks!

Alex

Re: [PATCH] vfio: Enable VFIO device for powerpc

[Paul Mackerras]

On Wed, Aug 26, 2015 at 11:34:26AM +0200, Alexander Graf wrote:
> 
> 
> On 13.08.15 03:15, 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>
> > Reviewed-by: Eric Auger <eric.auger@linaro.org>
> 
> Paul is going to take care of the kvm-ppc tree for 4.3. Also, ppc kvm
> patches should get CC on the kvm-ppc@vger mailing list ;).
> 
> Paul, could you please pick this one up?

Sure, I'll do that once I get home (end of this week).

Paul.

Re: [PATCH] vfio: Enable VFIO device for powerpc

[Paolo Bonzini]

On 26/08/2015 20:54, Paul Mackerras wrote:
> On Wed, Aug 26, 2015 at 11:34:26AM +0200, Alexander Graf wrote:
>>
>>
>> On 13.08.15 03:15, 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>
>>> Reviewed-by: Eric Auger <eric.auger@linaro.org>
>>
>> Paul is going to take care of the kvm-ppc tree for 4.3. Also, ppc kvm
>> patches should get CC on the kvm-ppc@vger mailing list ;).
>>
>> Paul, could you please pick this one up?
> 
> Sure, I'll do that once I get home (end of this week).

This was not in the 4.3 pull request, but I think we can apply it after
the end of the merge window.

Paolo

Re: [PATCH] vfio: Enable VFIO device for powerpc

[Paolo Bonzini]

On 26/08/2015 20:54, Paul Mackerras wrote:
> On Wed, Aug 26, 2015 at 11:34:26AM +0200, Alexander Graf wrote:
>> On 13.08.15 03:15, 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>
>>> Reviewed-by: Eric Auger <eric.auger@linaro.org>

This patch (commit 178a787502123) did not select CONFIG_KVM_VFIO, so the
patch did nothing---except causing build failures which I fixed in
commit 0af574be32cdd ("KVM: PPC: do not compile in vfio.o
unconditionally", 2016-03-21) by making the patch a total no-op.

Is KVM_VFIO really needed, and if so can this patch be fixed?

Thanks,

Paolo

Re: [PATCH] vfio: Enable VFIO device for powerpc

[Cornelia Huck]

On Thu, 11 Aug 2016 14:57:24 +0200
Paolo Bonzini <pbonzini@redhat.com> wrote:

> On 26/08/2015 20:54, Paul Mackerras wrote:
> > On Wed, Aug 26, 2015 at 11:34:26AM +0200, Alexander Graf wrote:
> >> On 13.08.15 03:15, 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>
> >>> Reviewed-by: Eric Auger <eric.auger@linaro.org>
> 
> This patch (commit 178a787502123) did not select CONFIG_KVM_VFIO, so the
> patch did nothing---except causing build failures which I fixed in
> commit 0af574be32cdd ("KVM: PPC: do not compile in vfio.o
> unconditionally", 2016-03-21) by making the patch a total no-op.
> 
> Is KVM_VFIO really needed, and if so can this patch be fixed?

FWIW, we enabled building vfio.o on s390 in 14b0b4a ("KVM: s390: Enable
the KVM-VFIO device") with the rationale "while we don't need it, be
like everybody else".

Should powerpc (and every other architecture supporting kvm and vfio)
select KVM_VFIO so that really everybody does the same thing?

Re: [PATCH] vfio: Enable VFIO device for powerpc

[Alexey Kardashevskiy]

On 11/08/16 23:19, Cornelia Huck wrote:
> On Thu, 11 Aug 2016 14:57:24 +0200
> Paolo Bonzini <pbonzini@redhat.com> wrote:
> 
>> On 26/08/2015 20:54, Paul Mackerras wrote:
>>> On Wed, Aug 26, 2015 at 11:34:26AM +0200, Alexander Graf wrote:
>>>> On 13.08.15 03:15, 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>
>>>>> Reviewed-by: Eric Auger <eric.auger@linaro.org>
>>
>> This patch (commit 178a787502123) did not select CONFIG_KVM_VFIO, so the
>> patch did nothing---except causing build failures which I fixed in
>> commit 0af574be32cdd ("KVM: PPC: do not compile in vfio.o
>> unconditionally", 2016-03-21) by making the patch a total no-op.
>>
>> Is KVM_VFIO really needed, and if so can this patch be fixed?
> 
> FWIW, we enabled building vfio.o on s390 in 14b0b4a ("KVM: s390: Enable
> the KVM-VFIO device") with the rationale "while we don't need it, be
> like everybody else".
> 
> Should powerpc (and every other architecture supporting kvm and vfio)
> select KVM_VFIO so that really everybody does the same thing?
> 

I recently posted one for ppc64/book3s:
https://patchwork.ozlabs.org/patch/655305/




-- 
Alexey

Re: [PATCH] vfio: Enable VFIO device for powerpc

[David Gibson]

[-- Attachment #1: Type: text/plain, Size: 2575 bytes --]

On Thu, Aug 11, 2016 at 03:19:57PM +0200, Cornelia Huck wrote:
> On Thu, 11 Aug 2016 14:57:24 +0200
> Paolo Bonzini <pbonzini@redhat.com> wrote:
> 
> > On 26/08/2015 20:54, Paul Mackerras wrote:
> > > On Wed, Aug 26, 2015 at 11:34:26AM +0200, Alexander Graf wrote:
> > >> On 13.08.15 03:15, 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>
> > >>> Reviewed-by: Eric Auger <eric.auger@linaro.org>
> > 
> > This patch (commit 178a787502123) did not select CONFIG_KVM_VFIO, so the
> > patch did nothing---except causing build failures which I fixed in
> > commit 0af574be32cdd ("KVM: PPC: do not compile in vfio.o
> > unconditionally", 2016-03-21) by making the patch a total no-op.
> > 
> > Is KVM_VFIO really needed, and if so can this patch be fixed?
> 
> FWIW, we enabled building vfio.o on s390 in 14b0b4a ("KVM: s390: Enable
> the KVM-VFIO device") with the rationale "while we don't need it, be
> like everybody else".
> 
> Should powerpc (and every other architecture supporting kvm and vfio)
> select KVM_VFIO so that really everybody does the same thing?

Yes, I think it should.  That was my intention when I sent that patch
- I just messed it up.

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 819 bytes --]

[PATCH] vfio: Enable VFIO device for powerpc

[David Gibson]

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>
Reviewed-by: Eric Auger <eric.auger@linaro.org>
---
 arch/powerpc/kvm/Makefile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

[RESEND?] I thought I sent this out some time ago.  Not sure if I
forgot, or if it fell through the cracks somewhere else.  In any case,
please apply.

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.
-- 
2.5.0