[pve-devel] [PATCH common/qemu-server] improve sysfs write behaviour

[Christoph Heiss]

Reviewed-by: Christoph Heiss <c.heiss at proxmox.com>
Tested-by: Christoph Heiss <c.heiss at proxmox.com>

Tested at least to the degree that this series does not regress
anything. (as I don't have any hardware to passthrough that exhibits
that problem in the first place)

On Tue, Nov 05, 2024 at 10:24:19AM +0100, Dominik Csapak wrote:
> As i feared previously in [0], making it a hard error when encountering
> errors during sysfs writes uncovered some situations where our code was
> too strict to keep some setups working.
>
> One such case is resetting devices, which is seemingly not necessary
> at all times, so this series
>
> * donwgrades that error to warning
> * adds some more logging to `file_write` to be able to better debug
>
> Alternatively, we could rewrite file_write such that we can control the
> error behaviour with a parameter and replace all "old" call sites so
> that we ignore errors. But since the only other call sites currently are
> for binding vfio-pci to the device. (which AFAIK is necessary and not
> optional) and setting mdev models (which is also not optional), we should
> mostly be fine with this approach here.
>
> In [1], some users reported it's breaking, at least one with binding of
> vfio-pci, which I'm currently investigating there to see if it's really
> necessary.
>
> 0: https://lore.proxmox.com/pve-devel/20240723082925.934603-1-d.csapak@proxmox.com/
> 1: https://forum.proxmox.com/threads/156848/
>
> pve-common:
>
> Dominik Csapak (1):
>   sysfstools: file_write: log the actual error if there was one
>
>  src/PVE/SysFSTools.pm | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
>
> qemu-server:
>
> Dominik Csapak (1):
>   pci: don't hard require resetting devices for passthrough
>
>  PVE/QemuServer/PCI.pm | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> --
> 2.39.5
>
>
>
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