Re: 回复: [edk2-devel] [PATCH v1 1/1] MdeModulePkg: Warn if out of flash space when writing variables

["Oliver Steffen" <osteffen@redhat.com>]

Quoting Laszlo Ersek (2024-03-05 08:33:57)
> On 3/5/24 01:40, gaoliming via groups.io wrote:
> > Oliver:
> >   If there is no enough space, Variable driver will reclaim flash and
> > reserve the enough space at boot time.
>
> What if the flash is genuinely fully occupied by *live* non-volatile
> variables?
>
> Laszlo
>
> >   At the runtime, reclaim will not be trigged. The space may be out of
> > resource. The warning message may be reported. Is this your case?
> >

Not exactly. It is like Laszlo describes in his question above.

Background:
We had the case where an OVMF based VM ran out of flash space after a
large number of reboots and hardware configuration changes. The MAC
address of the NIC was changing a lot over the life time of the VM. The
variable store was consumed entirely by networking related non-volatile
variables, written for each network card/MAC address present during
boot. Almost all of those were obsolete, of course, but the error that
presented itself at first was a VM that failed to boot the firmware and
ended up in an rather cryptic ASSERT message.

The hope is that this new message makes it easier for non-experts to
diagnose the situation.

The root cause is of course not addressed by this, but it might also be
hard to solve. One would have to identify obsolete network/hardware
settings somehow, but there is no way to tell if a certain NIC/MAC
might come back at a later point or not.

Thanks,
  Oliver

> > Thanks
> > Liming
> >> -----\u90ae\u4ef6\u539f\u4ef6-----
> >> \u53d1\u4ef6\u4eba: devel@edk2.groups.io <devel@edk2.groups.io> \u4ee3\u8868 Oliver Steffen
> >> \u53d1\u9001\u65f6\u95f4: 2024\u5e743\u67084\u65e5 23:18
> >> \u6536\u4ef6\u4eba: devel@edk2.groups.io
> >> \u6284\u9001: Oliver Steffen <osteffen@redhat.com>; Bob Feng
> >> <bob.c.feng@intel.com>; Liming Gao <gaoliming@byosoft.com.cn>; Rebecca
> >> Cran <rebecca@bsdio.com>; Yuwei Chen <yuwei.chen@intel.com>; Gerd
> >> Hoffmann <kraxel@redhat.com>; Laszlo Ersek <lersek@redhat.com>
> >> \u4e3b\u9898: [edk2-devel] [PATCH v1 1/1] MdeModulePkg: Warn if out of flash space
> >> when writing variables
> >>
> >> Emit a DEBUG_WARN message if there is not enough flash space left to
> >> write/update a variable. This condition is currently not logged
> >> appropriately in all cases, given that full variable store can easily
> >> render the system unbootable.
> >> This new message helps identifying this condition.
> >>
> >> Cc: Bob Feng <bob.c.feng@intel.com>
> >> Cc: Gerd Hoffmann <kraxel@redhat.com>
> >> Cc: Laszlo Ersek <lersek@redhat.com>
> >> Cc: Liming Gao <gaoliming@byosoft.com.cn>
> >> Cc: Rebecca Cran <rebecca@bsdio.com>
> >> Cc: Yuwei Chen <yuwei.chen@intel.com>
> >>
> >> Signed-off-by: Oliver Steffen <osteffen@redhat.com>
> >> ---
> >>  MdeModulePkg/Universal/Variable/RuntimeDxe/Variable.c | 2 ++
> >>  1 file changed, 2 insertions(+)
> >>
> >> diff --git a/MdeModulePkg/Universal/Variable/RuntimeDxe/Variable.c
> >> b/MdeModulePkg/Universal/Variable/RuntimeDxe/Variable.c
> >> index d394d237a53f..1c7659031dc5 100644
> >> --- a/MdeModulePkg/Universal/Variable/RuntimeDxe/Variable.c
> >> +++ b/MdeModulePkg/Universal/Variable/RuntimeDxe/Variable.c
> >> @@ -2364,6 +2364,8 @@ UpdateVariable (
> >>                    );
> >>
> >>        ASSERT_EFI_ERROR (Status);
> >>
> >>      }
> >>
> >> +  } else if (Status == EFI_OUT_OF_RESOURCES) {
> >>
> >> +    DEBUG ((DEBUG_WARN, "UpdateVariable failed: Out of flash
> >> space\n"));
> >>
> >>    }
> >>
> >>
> >>
> >>    return Status;
> >>
> >> --
> >> 2.44.0
> >>
> >>
> >>
> >>
> >>
> >
> >
> >
> >
> >
> > 
> >
> >
>

--
🎩Oliver Steffen (he/him) - Software Engineer, Virtualization
Red Hat GmbH <https://www.redhat.com/de/global/dach>,
Registered seat: Werner-von-Siemens-Ring 12, D-85630 Grasbrunn, Germany
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