| Message ID | 1623436283-20213-1-git-send-email-eric.devolder@oracle.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | acpi: Error Record Serialization Table, ERST, support for QEMU | expand |
On Fri, 11 Jun 2021 14:31:17 -0400 Eric DeVolder <eric.devolder@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.wilk@oracle.com> > Signed-off-by: Eric DeVolder <eric.devolder@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 >
Igor, Thanks for the feedback. I am working to address/correct the items. I hope to have v5 posted early next week. eric
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.wilk@oracle.com> Signed-off-by: Eric DeVolder <eric.devolder@oracle.com> --- v4: 11jun2021 - Converted to a PCI device, per Igor. - 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