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author | Peter Maydell <peter.maydell@linaro.org> | 2017-10-16 17:29:16 +0100 |
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committer | Peter Maydell <peter.maydell@linaro.org> | 2017-10-16 17:29:16 +0100 |
commit | c5bbcaa4b7c0f8a322bebe9ec563560178a68b55 (patch) | |
tree | df49749a080033a983e0080ad6ce58ffe8d119cf /docs | |
parent | 79b2a13aa81724228166c794f48eb75bfb696b88 (diff) | |
parent | ab06ec43577177a442e8e5ca28d0154efe4ff60f (diff) |
Merge remote-tracking branch 'remotes/mst/tags/for_upstream' into staging
pc, pci, virtio: fixes, features
A bunch of fixes all over the place.
A new vmcore device - the user interface around it is still somewhat
controversial, but I feel most of the code is fine, suggestions can be
addressed by adding patches on top.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
# gpg: Signature made Sun 15 Oct 2017 04:02:23 BST
# gpg: using RSA key 0x281F0DB8D28D5469
# gpg: Good signature from "Michael S. Tsirkin <mst@kernel.org>"
# gpg: aka "Michael S. Tsirkin <mst@redhat.com>"
# Primary key fingerprint: 0270 606B 6F3C DF3D 0B17 0970 C350 3912 AFBE 8E67
# Subkey fingerprint: 5D09 FD08 71C8 F85B 94CA 8A0D 281F 0DB8 D28D 5469
* remotes/mst/tags/for_upstream: (26 commits)
tests/pxe: Test more NICs when running in SPEED=slow mode
pc: remove useless hot_add_cpu initialisation
isapc: Remove unnecessary migration compatibility code
virtio-pci: Replace modern_as with direct access to modern_bar
virtio: fix descriptor counting in virtqueue_pop
hw/gen_pcie_root_port: make IO RO 0 on IO disabled
pci: Validate interfaces on base_class_init
xen/pt: Mark TYPE_XEN_PT_DEVICE as hybrid
pci: Add INTERFACE_CONVENTIONAL_PCI_DEVICE to Conventional PCI devices
pci: Add INTERFACE_PCIE_DEVICE to all PCIe devices
pci: Add interface names to hybrid PCI devices
pci: conventional-pci-device and pci-express-device interfaces
PCI: PCIe access should always be little endian
virtio/pci/migration: Convert to VMState
hw/pci-bridge/pcie_pci_bridge: properly handle MSI unavailability case
pci: allow 32-bit PCI IO accesses to pass through the PCI bridge
virtio/vhost: reset dev->log after syncing
MAINTAINERS: add Dump maintainers
scripts/dump-guest-memory.py: add vmcoreinfo
kdump: set vmcoreinfo location
...
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Diffstat (limited to 'docs')
-rw-r--r-- | docs/specs/vmcoreinfo.txt | 49 |
1 files changed, 49 insertions, 0 deletions
diff --git a/docs/specs/vmcoreinfo.txt b/docs/specs/vmcoreinfo.txt new file mode 100644 index 0000000000..821261067f --- /dev/null +++ b/docs/specs/vmcoreinfo.txt @@ -0,0 +1,49 @@ +================= +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. + +If the ELF note name is "VMCOREINFO", it is expected to be the Linux +vmcoreinfo note (see Documentation/ABI/testing/sysfs-kernel-vmcoreinfo +in Linux source). In this case, qemu dump code will read the content +as a key=value text file, looking for "NUMBER(phys_base)" key +value. The value is expected to be more accurate than architecture +guess of the value. This is useful for KASLR-enabled guest with +ancient tools not handling the VMCOREINFO note. |