On 01/17/2018 09:48 AM, Jonas Pfefferle wrote:
On Tue, 16 Jan 2018 18:01:32 +0100
Maxime Coquelin <maxime.coque...@redhat.com> wrote:
Hi Jonas,
On 01/16/2018 05:08 PM, Jonas Pfefferle wrote:
On Mon, 15 Jan 2018 17:11:58 +0100
Thomas Monjalon <tho...@monjalon.net> wrote:
15/01/2018 13:22, Jonas Pfefferle:
On Sat, 13 Jan 2018 23:49:30 +0100
Thomas Monjalon <tho...@monjalon.net> wrote:
> 13/01/2018 13:15, Burakov, Anatoly:
>> On 11-Jan-18 11:45 PM, Thomas Monjalon wrote:
>> > 07/11/2017 10:50, Jonas Pfefferle1:
>> >>> Is there something urgent for 17.11?
>> >>> Or can it be refined in 18.02?
>> >>
>> >> Nothing urgent. We can refine this for 18.02.
>> >>
>> >>> Anatoly, any thought?
>> > >> > Anatoly, Jonas, how do you want to proceed with this patch?
>> > >> >> I don't see anything to be refined here, it's a simple
bug fix - >>code >> assumes noiommu mode support is always
available, when it might not >>be >> the case on older kernels.
> > As a bug fix, the title must start with "fix" and a tag "Fixes:"
> must be added to help with backport.
> At the same time, the explanation of the bug must be added in
> the commit log please.
> > Thanks
It's not really a bug fix since it does not change the semantic of
the function but just adds nicer error handling.
Regarding redefining the code: What I don't like is the special
cases we have to check for when using the sPAPR iommu because it
does not support VA mappings yet. I think we should decide which
iova mode to use based on the iommu types available, i.e. each
iommu type should report which iova type it supports. Thoughts?
Have you looked at what Maxime did?
https://dpdk.org/dev/patchwork/patch/33650/
How does it affect this patch?
IMO it has the same problem. We shouldn't add more exception cases in
drivers/bus/pci/linux/pci.c but instead keep all the information
about what an IOMMU can do in lib/librte_eal/linuxapp/eal/eal_vfio.c
I agree adding an exception in drivers/bus/pci/linux/pci.c isn't great,
but we need first to fix a regression introduced in v17.11 LTS, and
IMHO, we cannot do a big rework as the fix is to be backported.
Once fixed, I agree we should work on a refactoring. I don't know if
eal_vfio is the right place though, as in my case for example I cannot
get the information needed through vfio ioctl().
Out of curiosity, what prevents sPAPR to use VA mode for now?
Maxime
Sounds good to me.
The current sPAPR Linux driver cannot use virtual addresses because the
DMA window size is restricted to RAM size and always starts at 0. This
is not a hardware restriction and we are working on allowing to create
arbitrary size windows.
Thanks for the clarification, is the DMA window size information
accessible from user-space, so that we can enable VA mode or not
depending on its value?
Maxime
Jonas
