The SPDX folks have obsoleted the BSD-2-Clause-FreeBSD identifier. Catch
up to that fact and revert to their recommended match of BSD-2-Clause.
Discussed with: pfg
MFC After: 3 days
Sponsored by: Netflix
This patch fixes virtual machine single stepping on VMX hosts.
Currently, when using bhyve's gdb stub, each attempt at single-stepping
a vCPU lands in a timer interrupt. The current single-stepping mechanism
uses the Monitor Trap Flag feature to cause VMEXIT after a single
instruction is executed. Unfortunately, the SDM states that MTF causes
VMEXITs for the next instruction that gets executed, which is often not
what the person using the debugger expects. [1]
This patch adds a new VM capability that masks interrupts on a vCPU by
blocking interrupt injection and modifies the gdb stub to use the newly
added capability while single-stepping a vCPU.
[1] Intel SDM 26.5.2 Vol. 3C
Reviewed by: corvink, jbh
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D39949
This replaces the 'struct vm, int vcpuid' tuple passed to most API
calls and is similar to the changes recently made in vmm(4) in the
kernel.
struct vcpu is an opaque type managed by libvmmapi. For now it stores
a pointer to the VM context and an integer id.
As an immediate effect this removes the divergence between the kernel
and userland for the instruction emulation code introduced by the
recent vmm(4) changes.
Since this is a major change to the vmmapi API, bump VMMAPI_VERSION to
0x200 (2.0) and the shared library major version.
While here (and since the major version is bumped), remove unused
vcpu argument from vm_setup_pptdev_msi*().
Add new functions vm_suspend_all_cpus() and vm_resume_all_cpus() for
use by the debug server. The underyling ioctl (which uses a vcpuid of
-1) remains unchanged, but the userlevel API now uses separate
functions for global CPU suspend/resume.
Reviewed by: corvink, markj
Differential Revision: https://reviews.freebsd.org/D38124
Allow user to specify the IP address available for gdb debugger.
Reviewed by: jhb, grehan, rgrimes, bcr (man pages)
Differential Revision: https://reviews.freebsd.org/D29607
The check needs to be in the public routine (gdb_cpu_suspend()), not
in the internal routine called from various places
(_gdb_cpu_suspend()). All the other callers of _gdb_cpu_suspend()
already check gdb_active, and this breaks the use of snapshots when
the debug server is not enabled since gdb_cpu_suspend() tries to lock
an uninitialized mutex.
Reported by: Darius Mihai, Elena Mihailescu
Reviewed by: elenamihailescu22_gmail.com
Fixes: 621b509048
Differential Revision: https://reviews.freebsd.org/D29538
Replace the existing ad-hoc configuration via various global variables
with a small database of key-value pairs. The database supports
heirarchical keys using a MIB-like syntax to name the path to a given
key. Values are always stored as strings. The API used to manage
configuation values does include wrappers to handling boolean values.
Other values use non-string types require parsing by consumers.
The configuration values are stored in a tree using nvlists. Leaf
nodes hold string values. Configuration values are permitted to
reference other configuration values using '%(name)'. This permits
constructing template configurations.
All existing command line arguments now set configuration values. For
devices, the "-s" option parses its option argument to generate a list
of key-value pairs for the given device.
A new '-o' command line option permits setting an individual
configuration variable. The key name is always given as a full path
of dot-separated components.
A new '-k' command line option parses a simple configuration file.
This configuration file holds a flat list of 'key=value' lines where
the 'key' is the full path of a configuration variable. Lines
starting with a '#' are comments.
In general, bhyve starts by parsing command line options in sequence
and applying those settings to configuration values. Once this is
complete, bhyve then begins initializing its state based on the
configuration values. This means that subsequent configuration
options or files may override or supplement previously given settings.
A special 'config.dump' configuration value can be set to true to help
debug configuration issues. When this value is set, bhyve will print
out the configuration variables as a flat list of 'key=value' lines.
Most command line argments map to a single configuration variable,
e.g. '-w' sets the 'x86.strictmsr' value to false. A few command
line arguments have less obvious effects:
- Multiple '-p' options append their values (as a comma-seperated
list) to "vcpu.N.cpuset" values (where N is a decimal vcpu number).
- For '-s' options, a pci.<bus>.<slot>.<function> node is created.
The first argument to '-s' (the device type) is used as the value of
a "device" variable. Additional comma-separated arguments are then
parsed into 'key=value' pairs and used to set additional variables
under the device node. A PCI device emulation driver can provide
its own hook to override the parsing of the additonal '-s' arguments
after the device type.
After the configuration phase as completed, the init_pci hook
then walks the "pci.<bus>.<slot>.<func>" nodes. It uses the
"device" value to find the device model to use. The device
model's init routine is passed a reference to its nvlist node
in the configuration tree which it can query for specific
variables.
The result is that a lot of the string parsing is removed from
the device models and centralized. In addition, adding a new
variable just requires teaching the model to look for the new
variable.
- For '-l' options, a similar model is used where the string is
parsed into values that are later read during initialization.
One key note here is that the serial ports use the commonly
used lowercase names from existing documentation and examples
(e.g. "lpc.com1") instead of the uppercase names previously
used internally in bhyve.
Reviewed by: grehan
MFC after: 3 months
Differential Revision: https://reviews.freebsd.org/D26035
- Allow the userland hypervisor to intercept breakpoint exceptions
(BP#) in the guest. A new capability (VM_CAP_BPT_EXIT) is used to
enable this feature. These exceptions are reported to userland via
a new VM_EXITCODE_BPT that includes the length of the original
breakpoint instruction. If userland wishes to pass the exception
through to the guest, it must be explicitly re-injected via
vm_inject_exception().
- Export VMCS_ENTRY_INST_LENGTH as a VM_REG_GUEST_ENTRY_INST_LENGTH
pseudo-register. Injecting a BP# on Intel requires setting this to
the length of the breakpoint instruction. AMD SVM currently ignores
writes to this register (but reports success) and fails to read it.
- Rework the per-vCPU state tracked by the debug server. Rather than
a single 'stepping_vcpu' global, add a structure for each vCPU that
tracks state about that vCPU ('stepping', 'stepped', and
'hit_swbreak'). A global 'stopped_vcpu' tracks which vCPU is
currently reporting an event. Event handlers for MTRAP and
breakpoint exits loop until the associated event is reported to the
debugger.
Breakpoint events are discarded if the breakpoint is not present
when a vCPU resumes in the breakpoint handler to retry submitting
the breakpoint event.
- Maintain a linked-list of active breakpoints in response to the GDB
'Z0' and 'z0' packets.
Reviewed by: markj (earlier version)
MFC after: 2 months
Differential Revision: https://reviews.freebsd.org/D20309
Coverity warned about gdb_write_mem sign extending the result of
parse_byte shifted left by 24 bits when generating a 32-bit memory
write value for MMIO. Simplify the code by using parse_integer
instead of unrolled parse_byte calls.
CID: 1401600
Reviewed by: cem
MFC after: 1 month
Differential Revision: https://reviews.freebsd.org/D20508
This doesn't recognize any features yet, but does parse the features
string. It advertises an arbitrary packet size of 4k.
Reviewed by: markj, Scott Phillips <d.scott.phillips@intel.com>
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D20308
- Add a write_mem counterpart to read_mem to handle writes to MMIO.
- Add support for the GDB 'M' packet to write bytes to the guest's
memory. For MMIO writes, attempt to batch writes up into words.
This is imprecise, but if you write a single 2 or 4-byte aligned
word, it should be treated as a single MMIO write operation.
- While here, tidy up the parsing of the 'm' command used for reading
memory to match 'M'.
Reviewed by: markj, Scott Phillips <d.scott.phillips@intel.com>
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D20307
will return success when the kernel is built without support of
the capability mode.
It is important to note, that I'm taking a more conservative approach
with these changes and it will be done in small steps.
Reviewed by: jhb
MFC after: 6 weeks
Differential Revision: https://reviews.freebsd.org/D18744
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
