This commit adds a new debug server to bhyve. Unlike the existing -g
option which provides an efficient connection to a debug server
running in the guest OS, this debug server permits inspection and
control of the guest from within the hypervisor itself without
requiring any cooperation from the guest. It is similar to the debug
server provided by qemu.
To avoid conflicting with the existing -g option, a new -G option has
been added that accepts a TCP port. An IPv4 socket is bound to this
port and listens for connections from debuggers. In addition, if the
port begins with the character 'w', the hypervisor will pause the
guest at the first instruction until a debugger attaches and
explicitly continues the guest. Note that only a single debugger can
attach to a guest at a time.
Virtual CPUs are exposed to the remote debugger as threads. General
purpose register values can be read for each virtual CPU. Other
registers cannot currently be read, and no register values can be
changed by the debugger.
The remote debugger can read guest memory but not write to guest
memory. To facilitate source-level debugging of the guest, memory
addresses from the debugger are treated as virtual addresses (rather
than physical addresses) and are resolved to a physical address using
the active virtual address translation of the current virtual CPU.
Memory reads should honor memory mapped I/O regions, though the debug
server does not attempt to honor any alignment or size constraints
when accessing MMIO.
The debug server provides limited support for controlling the guest.
The guest is suspended when a debugger is attached and resumes when a
debugger detaches. A debugger can suspend a guest by sending a Ctrl-C
request (e.g. via Ctrl-C in GDB). A debugger can also continue a
suspended guest while remaining attached. Breakpoints are not yet
supported. Single stepping is supported on Intel CPUs that support
MTRAP VM exits, but is not available on other systems.
While the current debug server has limited functionality, it should
at least be usable for basic debugging now. It is also a useful
checkpoint to serve as a base for adding additional features.
Reviewed by: grehan
Differential Revision: https://reviews.freebsd.org/D15022
from userland without the need to use sysctls, it allows the old
sysctls to continue to function, but deprecates them at
FreeBSD_version 1200060 (Relnotes for deprecate).
The command line of bhyve is maintained in a backwards compatible way.
The API of libvmmapi is maintained in a backwards compatible way.
The sysctl's are maintained in a backwards compatible way.
Added command option looks like:
bhyve -c [[cpus=]n][,sockets=n][,cores=n][,threads=n][,maxcpus=n]
The optional parts can be specified in any order, but only a single
integer invokes the backwards compatible parse. [,maxcpus=n] is
hidden by #ifdef until kernel support is added, though the api
is put in place.
bhyvectl --get-cpu-topology option added.
Reviewed by: grehan (maintainer, earlier version),
Reviewed by: bcr (manpages)
Approved by: bde (mentor), phk (mentor)
Tested by: Oleg Ginzburg <olevole@olevole.ru> (cbsd)
MFC after: 1 week
Relnotes: Y
Differential Revision: https://reviews.freebsd.org/D9930
The code was successfully tested with FreeBSD, Linux, Solaris and Windows
guests. This interface is predictably slower (about 2x) then virtio-net,
but it is very helpful for guests not supporting virtio-net by default.
Thanks to Jeremiah Lott and Peter Grehan for doing original heavy lifting.
While old syntax is still supported, new syntax looks like this:
-s 3,ahci,hd:/dev/zvol/XXX,hd:/dev/zvol/YYY,cd:/storage/ZZZ.iso
Sponsored by: iXsystems, Inc.
A couple of minor memory size option related nits:
- use common name 'memsize' (instead of 'max-size' or just 'size')
- bhyve: update usage with memsize unit suffix, drop legacy "MB"
unit
- bhyveload: update usage with memsize unit suffix
- bhyve(8): document default size
- bhyveload(8): use memsize formatting like it's done
in bhyve(8)
Reviewed by: wblock, grehan
Approved by: re (kib), wblock, grehan
Differential Revision: https://reviews.freebsd.org/D6952
devmem is used to represent MMIO devices like the boot ROM or a VESA framebuffer
where doing a trap-and-emulate for every access is impractical. devmem is a
hybrid of system memory (sysmem) and emulated device models.
devmem is mapped in the guest address space via nested page tables similar
to sysmem. However the address range where devmem is mapped may be changed
by the guest at runtime (e.g. by reprogramming a PCI BAR). Also devmem is
usually mapped RO or RW as compared to RWX mappings for sysmem.
Each devmem segment is named (e.g. "bootrom") and this name is used to
create a device node for the devmem segment (e.g. /dev/vmm/testvm.bootrom).
The device node supports mmap(2) and this decouples the host mapping of
devmem from its mapping in the guest address space (which can change).
Reviewed by: tychon
Discussed with: grehan
Differential Revision: https://reviews.freebsd.org/D2762
MFC after: 4 weeks
The default behavior is to infer the logical and physical sector sizes from
the block device backend. However older versions of Windows only work with
specific logical/physical combinations:
- Vista and Windows 7: 512/512
- Windows 7 SP1: 512/512 or 512/4096
For this reason allow the sector size to be specified using the following
block device option: sectorsize=logical[/physical]
Reported by: Leon Dang (ldang@nahannisys.com)
Reviewed by: grehan
MFC after: 2 weeks
The default remains localtime for compatibility with the original device model
in bhyve(8). This is required for OpenBSD guests which assume that the RTC
keeps UTC time.
Reviewed by: grehan
Pointed out by: Jason Tubnor (jason@tubnor.net)
MFC after: 2 weeks
similar to -g.)
- Document -U to set the SMBIOS UUID.
- Add missing options to the usage output and to the manpage Synopsis.
- Don't claim that bvmdebug is amd64-only (it is also a device, not an
option).
This has not added a lot of value when debugging bhyve issues while greatly
increasing the time and space required to store the core file.
Passing the "-C" option to bhyve(8) will change the default and dump guest
memory in the core dump.
Requested by: grehan
Reviewed by: grehan
a 'hostcpu'. The new format of the argument string is "vcpu:hostcpu".
This allows pinning a subset of the vcpus if desired.
It also allows pinning a vcpu to more than a single 'hostcpu'.
Submitted by: novel (initial version)
because there isn't a standard way to relay this information to the guest OS.
Add a command line option "-Y" to bhyve(8) to inhibit MPtable generation.
If the virtual machine is using PCI devices on buses other than 0 then it can
still use ACPI tables to convey this information to the guest.
Discussed with: grehan@
Call through to /dev/random synchronously to fill
virtio buffers with RNG data.
Tested with FreeBSD-CURRENT and Ubuntu guests.
Submitted by: Leon Dang
Discussed with: markm
MFC after: 3 weeks
Sponsored by: Nahanni Systems
