Re: [Qemu-devel] [PATCH qemu v2 0/4] spapr_pci, vfio: NVIDIA V100 + POWER9 passthrough

[David Gibson <david@gibson.dropbear.id.au>]

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On Fri, Feb 15, 2019 at 02:32:14PM +1100, Alexey Kardashevskiy wrote:
> 
> 
> On 15/02/2019 14:24, David Gibson wrote:
> > On Fri, Feb 15, 2019 at 11:35:02AM +1100, Alexey Kardashevskiy wrote:
> >>
> >>
> >> On 15/02/2019 10:37, Alex Williamson wrote:
> >>> On Thu, 14 Feb 2019 16:21:40 +1100
> >>> Alexey Kardashevskiy <aik@ozlabs.ru> wrote:
> >>>
> >>>> This is for passing through NVIDIA V100 GPUs on POWER9 systems.
> >>>>
> >>>> This implements a subdriver for NVIDIA V100 GPU with coherent memory and
> >>>> NPU/ATS support available in the POWER9 CPU.
> >>>>
> >>>> 1/4 is a preparation for bigger DMA windows.
> >>>> 2/4 is a small cleanup.
> >>>>
> >>>> Here is the kernel driver:
> >>>> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/drivers/vfio/pci?h=v5.0-rc6&id=7f92891778dff62303c070ac81de7b7d80de331a
> >>>>
> >>>> SLOF changes already went in.
> >>>>
> >>>> This depends on "pci: Move NVIDIA vendor id to the rest of ids" (posted separately).
> >>>
> >>> TBH, I'm not sure it was the best idea to let it live or die on it's
> >>> own when it now creates a build dependency for this series.
> >> I am sure that patch is disgustingly primitive and can make it to
> >> upstream in just one click and the rest of the series will take more
> >> time anyway (always does :) ).
> >>
> >>>> This is based on sha1
> >>>> 1ea6057 Mark Cave-Ayland "mac_newworld: change default NIC to sungem for mac99 machine".
> >>>
> >>> Perhaps this is why it doesn't apply cleanly against qemu.git.  Are
> >>> there dependencies we need to wait for in the ppc tree as well?
> >>
> >> There are few changes in spapr_pci so conflicts are possible, every time
> >> when David updates his tree and I rebase I get some minor ones.
> >>
> >>>> Please comment. Thanks.
> >>>
> >>> Besides the build dependency on PCI_VENDOR_ID_NVIDIA, I also get this:
> >>>
> >>> .../qemu.git/hw/vfio/spapr.c: In function ‘vfio_spapr_create_window’:
> >>> .../qemu.git/hw/vfio/spapr.c:212:9: error: ‘ret’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
> >>>          error_report("Failed to create a window, ret = %d (%m)", ret);
> >>>          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> >>> cc1: all warnings being treated as errors
> >>
> >> Agrh. How exactly do you make them errors, not warnings? I get no
> >> warning/error with --disable-werror but not having  --disable-werror
> >> prints warnings, not errors so it does not fail the build and easy to miss.
> > 
> > Are you sure it's printing warnings with --enable-werror?  Otherwise
> > it sounds like you just have a compiler version that's not picking
> > this up.
> 
> Ah, here is my mistake - I thought not having --disable-werror means
> that it is enabled as ./configure does not advertise  "--enable-werror":
> 
> [fstn1-p1 qemu]$ ./configure --help | grep werror
>   --disable-werror         disable compilation abort on warning
> 
> 
> Apparently it is a tri-state flag :)

Um.. no.. I believe it should be on by default as well, I was just
saying --enable-werror because I thought it was clearer than the
double negative in "without --disable-werror".

-- 
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

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