Add APEI/GHES description document Signed-off-by: Dongjiu Geng <gengdongjiu@xxxxxxxxxx> --- Address Igor's comments to add a doc --- docs/specs/acpi_hest_ghes.txt | 98 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 98 insertions(+) create mode 100644 docs/specs/acpi_hest_ghes.txt diff --git a/docs/specs/acpi_hest_ghes.txt b/docs/specs/acpi_hest_ghes.txt new file mode 100644 index 0000000..816d7b9 --- /dev/null +++ b/docs/specs/acpi_hest_ghes.txt @@ -0,0 +1,98 @@ +Generating APEI tables and record CPER +============================= + +Copyright (C) 2017 HuaWei Corporation. + +Design Details: +------------------- + + etc/acpi/tables etc/hardware_errors + ==================== ========================================== ++ +--------------------------+ +------------------+ +| | HEST | | address | +--------------+ +| +--------------------------+ | registers | | Error Status | +| | GHES1 | | +----------------+ | Data Block 1 | +| +--------------------------+ +--------->| |status_address1 |------------->| +------------+ +| | ................. | | | +----------------+ | | CPER | +| | error_status_address-----+-+ +------->| |status_address2 |----------+ | | CPER | +| | ................. | | | +----------------+ | | | .... | +| | read_ack_register--------+-+ | | ............. | | | | CPER | +| | read_ack_preserve | | | +------------------+ | | +------------+ +| | read_ack_write | | | +----->| |status_addressN |--------+ | | Error Status | ++ +--------------------------+ | | | | +----------------+ | | | Data Block 2 | +| | GHES2 | +-+-+----->| | ack_value1 | | +-->| +------------+ ++ +--------------------------+ | | | +----------------+ | | | CPER | +| | ................. | | | +--->| | ack_value2 | | | | CPER | +| | error_status_address-----+---+ | | | +----------------+ | | | .... | +| | ................. | | | | | ............. | | | | CPER | +| | read_ack_register--------+-----+-+ | +----------------+ | +-+------------+ +| | read_ack_preserve | | +->| | ack_valueN | | | |.......... | +| | read_ack_write | | | | +----------------+ | | +------------+ ++ +--------------------------| | | | | Error Status | +| | ............... | | | | | Data Block N | ++ +--------------------------+ | | +---->| +------------+ +| | GHESN | | | | | CPER | ++ +--------------------------+ | | | | CPER | +| | ................. | | | | | .... | +| | error_status_address-----+-----+ | | | CPER | +| | ................. | | +-+------------+ +| | read_ack_register--------+---------+ +| | read_ack_preserve | +| | read_ack_write | ++ +--------------------------+ + +(1) QEMU generates the ACPI HEST table. This table goes in the current + "etc/acpi/tables" fw_cfg blob. Each error source has different + notification type. + +(2) A new fw_cfg blob called "etc/hardware_errors" is introduced. QEMU + also need to populate this blob. The "etc/hardwre_errors" fw_cfg blob contains + one address registers table and one Error Status Data Block table, all + of which are pre-allocated. + +(3) The address registers table contains N Error Status Address entries + and N Read Ack Address entries, the size for each entry is 8-byte. The + Error Status Data Block table contains N Error Status Data Block entry, + the size for each entry is 0x1000(4096) bytes. The total size for + "etc/hardware_errors" fw_cfg blob is (N * 8 * 2 + N * 4096) bytes + +(4) QEMU generates the ACPI linker/loader script for the firmware + +(4a) The HEST table is part of "etc/acpi/tables", which the firmware + already allocates memory for it and downloads, because QEMU already + generates an ALLOCATE linker/loader command for it. + +(4b) QEMU creates another ALLOCATE command for the "etc/hardware_errors" + blob. The firmware allocates memory for this blob, + and downloads it. + +(5) QEMU generates, N ADD_POINTER commands, which patch address in the + "Error Status Address" fields of the HEST table with a pointer to the + corresponding address registers in the downloaded "etc/hardware_errors" blob. + +(6) QEMU generates N ADD_POINTER commands for the firmware, pointing the + address registers (located in guest memory, in the downloaded + "etc/hardware_errors" blob) to the respective Error Status Data Blocks. + +(7) QEMU Defines a third, write-only fw_cfg blob, called "etc/hardware_errors_addr". + Through that blob, the firmware can send back the guest-side allocation addresses + to QEMU. The "etc/hardware_errors_addr" blob contains a 8-byte entry. QEMU generates + a single WRITE_POINTER commands for the firmware, the firmware will write the start + address of Error Status Data Block0 back to fw_cfg file "etc/hardware_errors_addr". + Then Qemu will know the start address of Error Status Data Block0. For error source K + (0 <= K < 2), its address offset is K * 0x1000, because each of Error Status Data Block + has fixed size which is 0x1000. Using this way, QEMU will know the address of each + Error Status Data Block. + +(8) When QEMU gets SIGBUS from the kernel, QEMU format the CPER right into guest + memory, and then inject whatever interrupt (or assert whatever GPIO line) which is + necessary for notifying the guest. + +(9) This notification (in virtual hardware) can either be handled by the + guest kernel stand-alone, or else the guest kernel can invoke an ACPI + event handler method with it. The ACPI event handler method could + invoke the specific guest kernel driver for error handling via a + Notify() operation. + +For the above design, it would leave the firmware alone after OS boot and firmware no need +to care about HEST, GHES, CPER. -- 1.8.3.1
