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authorPeter Maydell <peter.maydell@linaro.org>2017-10-16 17:29:16 +0100
committerPeter Maydell <peter.maydell@linaro.org>2017-10-16 17:29:16 +0100
commitc5bbcaa4b7c0f8a322bebe9ec563560178a68b55 (patch)
treedf49749a080033a983e0080ad6ce58ffe8d119cf /docs
parent79b2a13aa81724228166c794f48eb75bfb696b88 (diff)
parentab06ec43577177a442e8e5ca28d0154efe4ff60f (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.txt49
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.