From: Dongjiu Geng <gengdongjiu@xxxxxxxxxx>
Add APEI/GHES detailed design document
Signed-off-by: Dongjiu Geng <gengdongjiu@xxxxxxxxxx>
Signed-off-by: Xiang Zheng <zhengxiang9@xxxxxxxxxx>
---
docs/specs/acpi_hest_ghes.rst | 95 +++++++++++++++++++++++++++++++++++
docs/specs/index.rst | 1 +
2 files changed, 96 insertions(+)
create mode 100644 docs/specs/acpi_hest_ghes.rst
diff --git a/docs/specs/acpi_hest_ghes.rst b/docs/specs/acpi_hest_ghes.rst
new file mode 100644
index 0000000000..348825f9d3
--- /dev/null
+++ b/docs/specs/acpi_hest_ghes.rst
@@ -0,0 +1,95 @@
+APEI tables generating and CPER record
+======================================
+
+..
+ Copyright (c) 2019 HUAWEI TECHNOLOGIES CO., LTD.
+
+ This work is licensed under the terms of the GNU GPL, version 2 or later.
+ See the COPYING file in the top-level directory.
+
+Design Details
+--------------
+
+::
+
+ etc/acpi/tables etc/hardware_errors
+ ==================== ==========================================
+ + +--------------------------+ +-----------------------+
+ | | HEST | | address | +--------------+
+ | +--------------------------+ | registers | | Error Status |
+ | | GHES1 | | +---------------------+ | Data Block 1 |
+ | +--------------------------+ +--------->| |error_block_address1 |----------->| +------------+
+ | | ................. | | | +---------------------+ | | CPER |
+ | | error_status_address-----+-+ +------->| |error_block_address2 |--------+ | | CPER |
+ | | ................. | | | +---------------------+ | | | .... |
+ | | read_ack_register--------+-+ | | | .............. | | | | CPER |
+ | | read_ack_preserve | | | +-----------------------+ | | +------------+
+ | | read_ack_write | | | +----->| |error_block_addressN |------+ | | Error Status |
+ + +--------------------------+ | | | | +---------------------+ | | | Data Block 2 |
+ | | GHES2 | +-+-+----->| |read_ack_register1 | | +-->| +------------+
+ + +--------------------------+ | | | +---------------------+ | | | CPER |
+ | | ................. | | | +--->| |read_ack_register2 | | | | CPER |
+ | | error_status_address-----+---+ | | | +---------------------+ | | | .... |
+ | | ................. | | | | | ............. | | | | CPER |
+ | | read_ack_register--------+-----+-+ | +---------------------+ | +-+------------+
+ | | read_ack_preserve | | +->| |read_ack_registerN | | | |.......... |
+ | | 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 types.
+
+(2) A new fw_cfg blob called "etc/hardware_errors" is introduced. QEMU
+ also needs to populate this blob. The "etc/hardware_errors" fw_cfg blob
+ contains an address registers table and an Error Status Data Block table.
+
+(3) The address registers table contains N Error Block Address entries
+ and N Read Ack Register entries. The size for each entry is 8-byte.
+ The Error Status Data Block table contains N Error Status Data Block
+ entries. The size for each entry is 4096(0x1000) bytes. The total size
+ for the "etc/hardware_errors" fw_cfg blob is (N * 8 * 2 + N * 4096) bytes.
+ N is the number of the kinds of hardware error sources.
+
+(4) QEMU generates the ACPI linker/loader script for the firmware. The
+ firmware pre-allocates memory for "etc/acpi/tables", "etc/hardware_errors"
+ and copies blob contents there.
+
+(5) QEMU generates N ADD_POINTER commands, which patch addresses in the
+ "error_status_address" fields of the HEST table with a pointer to the
+ corresponding "address registers" in the "etc/hardware_errors" blob.
+
+(6) QEMU generates N ADD_POINTER commands, which patch addresses in the
+ "read_ack_register" fields of the HEST table with a pointer to the
+ corresponding "address registers" in the "etc/hardware_errors" blob.
+
+(7) QEMU generates N ADD_POINTER commands for the firmware, which patch
+ addresses in the "error_block_address" fields with a pointer to the
+ respective "Error Status Data Block" in the "etc/hardware_errors" blob.
+
+(8) QEMU defines a third and write-only fw_cfg blob which is 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 command
+ for the firmware. The firmware will write back the start address of
+ "etc/hardware_errors" blob to the fw_cfg file "etc/hardware_errors_addr".
+
+(9) When QEMU gets a SIGBUS from the kernel, QEMU formats the CPER right into
+ guest memory, and then injects platform specific interrupt (in case of
+ arm/virt machine it's Synchronous External Abort) as a notification which
+ is necessary for notifying the guest.
+
+(10) This notification (in virtual hardware) will be handled by the guest
+ kernel, guest APEI driver will read the CPER which is recorded by QEMU and
+ do the recovery.
diff --git a/docs/specs/index.rst b/docs/specs/index.rst
index 984ba44029..3019b9c976 100644
--- a/docs/specs/index.rst
+++ b/docs/specs/index.rst
@@ -13,3 +13,4 @@ Contents:
ppc-xive
ppc-spapr-xive
acpi_hw_reduced_hotplug
+ acpi_hest_ghes
--
2.19.1
