NOTE: Also, I wanted to push this v3 for review while alerting
that I will be on holiday through June 8 (possibly a few days
later).
NOTE: The patches are arranged such that each can be applied
in order and not break the build (except the 0001 patch). Igor
has hinted at changing this, but I'm unsure how else to
re-arrange these patches accordingly.
NOTE: With the conversion to TYPE_MEMORY_BACKEND_FILE, live
migration to a completely different host does not behave
properly (it loses the ERST contents because the file is not
present on the new host). This still needs to be worked out.
Other than live migration, this patchset fully works.
This patchset introduces support for the ACPI Error Record
Serialization Table, ERST.
Linux uses the persistent storage filesystem, pstore, to record
information (eg. dmesg tail) upon panics and shutdowns. Pstore is
independent of, and runs before, kdump. In certain scenarios (ie.
hosts/guests with root filesystems on NFS/iSCSI where networking
software and/or hardware fails), pstore may contain the only
information available for post-mortem debugging.
Two common storage backends for the pstore filesystem are ACPI ERST
and UEFI. Most BIOS implement ACPI ERST; however, ACPI ERST is not
currently supported in QEMU, and UEFI is not utilized in all guests.
By implementing ACPI ERST within QEMU, then the ACPI ERST becomes a
viable pstore storage backend for virtual machines (as it is now for
bare metal machines).
Enabling support for ACPI ERST facilitates a consistent method to
capture kernel panic information in a wide range of guests: from
resource-constrained microvms to very large guests, and in
particular, in direct-boot environments (which would lack UEFI
run-time services).
Note that Microsoft Windows also utilizes the ACPI ERST for certain
crash information, if available.
The ACPI ERST persistent storage is contained within a single backing
file, with a default size of 64KiB. The size and filename of the
backing file can be obtained from QEMU parameters.
The ACPI specification[1], in Chapter "ACPI Platform Error Interfaces
(APEI)", and specifically subsection "Error Serialization", outlines
a method for storing error records into persistent storage.
[1] "Advanced Configuration and Power Interface Specification",
version 6.2, May 2017.
https://www.uefi.org/sites/default/files/resources/ACPI_6_2.pdf
[2] "Unified Extensible Firmware Interface Specification",
version 2.8, March 2019.
https://uefi.org/sites/default/files/resources/UEFI_Spec_2_8_final.pdf
Suggested-by: Konrad Wilk <konrad.w...@oracle.com>
Signed-off-by: Eric DeVolder <eric.devol...@oracle.com>
---
v3: 28may2021
- Converted to using a TYPE_MEMORY_BACKEND_FILE object rather than
internal array with explicit file operations, per Igor.
- Changed the way the qdev and base address are handled, allowing
ERST to be disabled at run-time. Also aligns better with other
existing code.
v2: 8feb2021
- Added qtest/smoke test per Paolo Bonzini
- Split patch into smaller chunks, per Igo Mammedov
- Did away with use of ACPI packed structures, per Igo Mammedov
v1: 26oct2020
- initial post
---
hw/acpi/erst.c | 909 +++++++++++++++++++++++++++++++++++++++++++++++++
hw/acpi/meson.build | 1 +
hw/i386/acpi-build.c | 4 +
include/hw/acpi/erst.h | 97 ++++++
4 files changed, 1011 insertions(+)
create mode 100644 hw/acpi/erst.c
create mode 100644 include/hw/acpi/erst.h
Eric DeVolder (7):
ACPI ERST: bios-tables-test.c steps 1 and 2
ACPI ERST: header file for ERST
ACPI ERST: support for ACPI ERST feature
ACPI ERST: include ERST feature in build of ACPI support
ACPI ERST: create ERST device for pc/x86 machines.
ACPI ERST: qtest for ERST
ACPI ERST: step 6 of bios-tables-test.c
hw/acpi/erst.c | 902 +++++++++++++++++++++++++++++++++++++++++++
hw/acpi/meson.build | 1 +
hw/i386/acpi-build.c | 7 +
hw/i386/pc.c | 31 ++
include/hw/acpi/erst.h | 82 ++++
include/hw/i386/pc.h | 1 +
tests/data/acpi/microvm/ERST | 0
tests/data/acpi/pc/ERST | Bin 0 -> 976 bytes
tests/data/acpi/q35/ERST | Bin 0 -> 976 bytes
tests/qtest/erst-test.c | 106 +++++
tests/qtest/meson.build | 2 +
11 files changed, 1132 insertions(+)
create mode 100644 hw/acpi/erst.c
create mode 100644 include/hw/acpi/erst.h
create mode 100644 tests/data/acpi/microvm/ERST
create mode 100644 tests/data/acpi/pc/ERST
create mode 100644 tests/data/acpi/q35/ERST
create mode 100644 tests/qtest/erst-test.c
--
1.8.3.1
