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

[Dominik Csapak]

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(-)

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2.39.5