On Fri, 11 Jun 2021 14:31:17 -0400 Eric DeVolder <eric.devol...@oracle.com> wrote:
> 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. The size and location of the backing file is specified upon > QEMU startup of the ACPI ERST device. > > 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> > > --- > v4: 11jun2021 > - Converted to a PCI device, per Igor. Series looks much better now that impl. were split into backend/frontend parts and dynamic MMIO placement. I left some mandatory nit-picking about comments, styles, overall documentation, leftovers from previous revisions. And also some how we can simplify impl. a bit more. > - Updated qtest. > > 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 > > --- > Eric DeVolder (6): > 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: create ACPI ERST table for pc/x86 machines. > ACPI ERST: qtest for ERST > ACPI ERST: step 6 of bios-tables-test.c > > hw/acpi/erst.c | 880 > +++++++++++++++++++++++++++++++++++++++++++ > hw/acpi/meson.build | 1 + > hw/i386/acpi-build.c | 5 + > include/hw/acpi/erst.h | 79 ++++ > 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 | 109 ++++++ > tests/qtest/meson.build | 2 + > 9 files changed, 1076 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 >
