From 6e43353f10c6688060af0bc26bdfdd4cf9c96ea2 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= Date: Mon, 11 Sep 2017 18:59:24 +0200 Subject: hw/misc: add vmcoreinfo device MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit See docs/specs/vmcoreinfo.txt for details. "etc/vmcoreinfo" fw_cfg entry is added when using "-device vmcoreinfo". Signed-off-by: Marc-André Lureau Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin --- docs/specs/vmcoreinfo.txt | 41 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 41 insertions(+) create mode 100644 docs/specs/vmcoreinfo.txt (limited to 'docs') diff --git a/docs/specs/vmcoreinfo.txt b/docs/specs/vmcoreinfo.txt new file mode 100644 index 0000000..2868a77 --- /dev/null +++ b/docs/specs/vmcoreinfo.txt @@ -0,0 +1,41 @@ +================= +VMCoreInfo device +================= + +The `-device vmcoreinfo` will create a fw_cfg entry for a guest to +store dump details. + +etc/vmcoreinfo +************** + +A guest may use this fw_cfg entry to add information details to qemu +dumps. + +The entry of 16 bytes has the following layout, in little-endian:: + +#define VMCOREINFO_FORMAT_NONE 0x0 +#define VMCOREINFO_FORMAT_ELF 0x1 + + struct FWCfgVMCoreInfo { + uint16_t host_format; /* formats host supports */ + uint16_t guest_format; /* format guest supplies */ + uint32_t size; /* size of vmcoreinfo region */ + uint64_t paddr; /* physical address of vmcoreinfo region */ + }; + +Only full write (of 16 bytes) are considered valid for further +processing of entry values. + +A write of 0 in guest_format will disable further processing of +vmcoreinfo entry values & content. + +Format & content +**************** + +As of qemu 2.11, only VMCOREINFO_FORMAT_ELF is supported. + +The entry gives location and size of an ELF note that is appended in +qemu dumps. + +The note format/class must be of the target bitness and the size must +be less than 1Mb. -- cgit v1.1