diff options
Diffstat (limited to 'docs')
| -rw-r--r-- | docs/specs/vmcoreinfo.txt | 41 |
1 files changed, 41 insertions, 0 deletions
diff --git a/docs/specs/vmcoreinfo.txt b/docs/specs/vmcoreinfo.txt new file mode 100644 index 0000000000..2868a77142 --- /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. |