virt-manager/virtinst/domcapabilities.py
Cole Robinson 2c477f3302 domain: cpu: Use host-passthrough by default on x86
When libvirt and qemu are new enough, use host-passthrough for the
CPU default. Nowadays this is recommended over host-model for most
end user usage where migration isn't a critical feature.

Signed-off-by: Cole Robinson <crobinso@redhat.com>
2022-02-16 14:03:44 -05:00

419 lines
14 KiB
Python

#
# Support for parsing libvirt's domcapabilities XML
#
# Copyright 2014 Red Hat, Inc.
#
# This work is licensed under the GNU GPLv2 or later.
# See the COPYING file in the top-level directory.
import re
import xml.etree.ElementTree as ET
import libvirt
from .domain import DomainCpu
from .logger import log
from .xmlbuilder import XMLBuilder, XMLChildProperty, XMLProperty
########################################
# Genering <enum> and <value> handling #
########################################
class _Value(XMLBuilder):
XML_NAME = "value"
value = XMLProperty(".")
class _HasValues(XMLBuilder):
values = XMLChildProperty(_Value)
def get_values(self):
return [v.value for v in self.values]
class _Enum(_HasValues):
XML_NAME = "enum"
name = XMLProperty("./@name")
class _CapsBlock(_HasValues):
supported = XMLProperty("./@supported", is_yesno=True)
enums = XMLChildProperty(_Enum)
def enum_names(self):
return [e.name for e in self.enums]
def has_enum(self, name):
return name in self.enum_names()
def get_enum(self, name):
for enum in self.enums:
if enum.name == name:
return enum
# Didn't find a match. Could be talking to older libvirt, or
# driver with incomplete info. Return a stub enum
return _Enum(self.conn)
def _make_capsblock(xml_root_name):
"""
Build a class object representing a list of <enum> in the XML. For
example, domcapabilities may have a block like:
<graphics supported='yes'>
<enum name='type'>
<value>sdl</value>
<value>vnc</value>
<value>spice</value>
</enum>
</graphics>
To build a class that tracks that whole <graphics> block, call this
like _make_capsblock("graphics")
"""
class TmpClass(_CapsBlock):
pass
setattr(TmpClass, "XML_NAME", xml_root_name)
return TmpClass
################################
# SEV launch security handling #
################################
class _SEV(XMLBuilder):
XML_NAME = "sev"
supported = XMLProperty("./@supported", is_yesno=True)
cbitpos = XMLProperty("./cbitpos", is_int=True)
reducedPhysBits = XMLProperty("./reducedPhysBits", is_int=True)
#############################
# Misc toplevel XML classes #
#############################
class _OS(_CapsBlock):
XML_NAME = "os"
loader = XMLChildProperty(_make_capsblock("loader"), is_single=True)
class _Devices(_CapsBlock):
XML_NAME = "devices"
hostdev = XMLChildProperty(_make_capsblock("hostdev"), is_single=True)
disk = XMLChildProperty(_make_capsblock("disk"), is_single=True)
video = XMLChildProperty(_make_capsblock("video"), is_single=True)
graphics = XMLChildProperty(_make_capsblock("graphics"), is_single=True)
tpm = XMLChildProperty(_make_capsblock("tpm"), is_single=True)
filesystem = XMLChildProperty(_make_capsblock("filesystem"), is_single=True)
class _Features(_CapsBlock):
XML_NAME = "features"
gic = XMLChildProperty(_make_capsblock("gic"), is_single=True)
sev = XMLChildProperty(_SEV, is_single=True)
class _MemoryBacking(_CapsBlock):
XML_NAME = "memoryBacking"
###############
# CPU classes #
###############
class _CPUModel(XMLBuilder):
XML_NAME = "model"
model = XMLProperty(".")
usable = XMLProperty("./@usable")
fallback = XMLProperty("./@fallback")
class _CPUMode(_CapsBlock):
XML_NAME = "mode"
name = XMLProperty("./@name")
models = XMLChildProperty(_CPUModel)
def get_model(self, name):
for model in self.models:
if model.model == name:
return model
class _CPU(XMLBuilder):
XML_NAME = "cpu"
modes = XMLChildProperty(_CPUMode)
def get_mode(self, name):
for mode in self.modes:
if mode.name == name:
return mode
#################################
# DomainCapabilities main class #
#################################
class DomainCapabilities(XMLBuilder):
@staticmethod
def build_from_params(conn, emulator, arch, machine, hvtype):
xml = None
if conn.support.conn_domain_capabilities():
try:
xml = conn.getDomainCapabilities(emulator, arch,
machine, hvtype)
except Exception: # pragma: no cover
log.debug("Error fetching domcapabilities XML",
exc_info=True)
if not xml:
# If not supported, just use a stub object
return DomainCapabilities(conn)
return DomainCapabilities(conn, parsexml=xml)
@staticmethod
def build_from_guest(guest):
return DomainCapabilities.build_from_params(guest.conn,
guest.emulator, guest.os.arch, guest.os.machine, guest.type)
# Mapping of UEFI binary names to their associated architectures. We
# only use this info to do things automagically for the user, it shouldn't
# validate anything the user explicitly enters.
_uefi_arch_patterns = {
"i686": [
r".*edk2-i386-.*\.fd", # upstream qemu
r".*ovmf-ia32.*", # fedora, gerd's firmware repo
],
"x86_64": [
r".*edk2-x86_64-.*\.fd", # upstream qemu
r".*OVMF_CODE\.fd", # RHEL
r".*ovmf-x64/OVMF.*\.fd", # gerd's firmware repo
r".*ovmf-x86_64-.*", # SUSE
r".*ovmf.*", ".*OVMF.*", # generic attempt at a catchall
],
"aarch64": [
r".*AAVMF_CODE\.fd", # RHEL
r".*aarch64/QEMU_EFI.*", # gerd's firmware repo
r".*aarch64.*", # generic attempt at a catchall
r".*edk2-aarch64-code\.fd", # upstream qemu
],
"armv7l": [
r".*AAVMF32_CODE\.fd", # Debian qemu-efi-arm package
r".*arm/QEMU_EFI.*", # fedora, gerd's firmware repo
r".*edk2-arm-code\.fd" # upstream qemu
],
}
def find_uefi_path_for_arch(self):
"""
Search the loader paths for one that matches the passed arch
"""
if not self.arch_can_uefi():
return # pragma: no cover
firmware_files = [f.value for f in self.os.loader.values]
if self.conn.is_bhyve():
for firmware_file in firmware_files:
if 'BHYVE_UEFI.fd' in firmware_file:
return firmware_file
return (firmware_files and
firmware_files[0] or None) # pragma: no cover
patterns = self._uefi_arch_patterns.get(self.arch)
for pattern in patterns:
for path in firmware_files:
if re.match(pattern, path):
return path
def label_for_firmware_path(self, path):
"""
Return a pretty label for passed path, based on if we know
about it or not
"""
if not path:
if self.arch in ["i686", "x86_64"]:
return _("BIOS")
return _("Default")
for arch, patterns in self._uefi_arch_patterns.items():
for pattern in patterns:
if re.match(pattern, path):
return (_("UEFI %(arch)s: %(path)s") %
{"arch": arch, "path": path})
return _("Custom: %(path)s" % {"path": path})
def arch_can_uefi(self):
"""
Return True if we know how to setup UEFI for the passed arch
"""
return self.arch in list(self._uefi_arch_patterns.keys())
def supports_uefi_loader(self):
"""
Return True if libvirt advertises support for UEFI loader
"""
return "yes" in self.os.loader.get_enum("readonly").get_values()
def supports_firmware_efi(self):
return "efi" in self.os.get_enum("firmware").get_values()
def supports_safe_host_model(self):
"""
Return True if domcaps reports support for cpu mode=host-model.
host-model in fact predates this support, however it wasn't
general purpose safe prior to domcaps advertisement.
"""
m = self.cpu.get_mode("host-model")
return (m and m.supported and
m.models[0].fallback == "forbid")
def supports_safe_host_passthrough(self):
"""
Return True if host-passthrough is safe enough to use by default.
We limit this to domcaps new enough to report whether host-passthrough
is migratable or not, which also means libvirt is about new enough
to not taint the VM for using host-passthrough
"""
m = self.cpu.get_mode("host-passthrough")
return (m and m.supported and
"on" in m.get_enum("hostPassthroughMigratable").get_values())
def get_cpu_models(self):
models = []
for m in self.cpu.modes:
if m.name == "custom" and m.supported:
for model in m.models:
if model.usable != "no":
models.append(model.model)
return models
def _convert_mode_to_cpu(self, xml):
root = ET.fromstring(xml)
root.tag = "cpu"
root.attrib = {}
arch = ET.SubElement(root, "arch")
arch.text = self.arch
return ET.tostring(root, encoding="unicode")
def _get_expanded_cpu(self, mode):
cpuXML = self._convert_mode_to_cpu(mode.get_xml())
log.debug("Generated CPU XML for security flag baseline:\n%s", cpuXML)
try:
expandedXML = self.conn.baselineHypervisorCPU(
self.path, self.arch, self.machine, self.domain, [cpuXML],
libvirt.VIR_CONNECT_BASELINE_CPU_EXPAND_FEATURES)
except (libvirt.libvirtError, AttributeError):
expandedXML = self.conn.baselineCPU([cpuXML],
libvirt.VIR_CONNECT_BASELINE_CPU_EXPAND_FEATURES)
return DomainCpu(self.conn, expandedXML)
def _lookup_cpu_security_features(self):
ret = []
sec_features = [
'spec-ctrl',
'ssbd',
'ibpb',
'virt-ssbd',
'md-clear']
for m in self.cpu.modes:
if m.name != "host-model" or not m.supported:
continue # pragma: no cover
try:
cpu = self._get_expanded_cpu(m)
except libvirt.libvirtError as e: # pragma: no cover
log.warning(_("Failed to get expanded CPU XML: %s"), e)
break
for feature in cpu.features:
if feature.name in sec_features:
ret.append(feature.name)
log.debug("Found host-model security features: %s", ret)
return ret
_features = None
def get_cpu_security_features(self):
if self._features is None:
self._features = self._lookup_cpu_security_features() or []
return self._features
def supports_sev_launch_security(self):
"""
Returns False if either libvirt doesn't advertise support for SEV at
all (< libvirt-4.5.0) or if it explicitly advertises it as unsupported
on the platform
"""
return bool(self.features.sev.supported)
def supports_video_bochs(self):
"""
Returns False if either libvirt or qemu do not have support to bochs
video type.
"""
models = self.devices.video.get_enum("modelType").get_values()
return bool("bochs" in models)
def supports_video_qxl(self):
if not self.devices.video.has_enum("modelType"):
# qxl long predates modelType in domcaps, so if it is missing,
# use spice support as a rough value
return self.supports_graphics_spice()
return "qxl" in self.devices.video.get_enum("modelType").get_values()
def supports_video_virtio(self):
return "virtio" in self.devices.video.get_enum("modelType").get_values()
def supports_tpm_emulator(self):
"""
Returns False if either libvirt or qemu do not have support for
emulating a TPM.
"""
models = self.devices.tpm.get_enum("model").get_values()
backends = self.devices.tpm.get_enum("backendModel").get_values()
return len(models) > 0 and bool("emulator" in backends)
def supports_graphics_spice(self):
if not self.devices.graphics.supported:
# domcaps is too old, or the driver doesn't advertise graphics
# support. Use our pre-existing logic
if not self.conn.is_qemu() and not self.conn.is_test():
return False
return self.conn.caps.host.cpu.arch in ["i686", "x86_64"]
types = self.devices.graphics.get_enum("type").get_values()
return bool("spice" in types)
def supports_filesystem_virtiofs(self):
"""
Return True if libvirt advertises support for virtiofs
"""
types = self.devices.filesystem.get_enum("driverType").get_values()
return bool("virtiofs" in types)
def supports_memorybacking_memfd(self):
"""
Return True if libvirt advertises support for memfd memory backend
"""
sourceTypes = self.memorybacking.get_enum("sourceType").get_values()
return bool("memfd" in sourceTypes)
XML_NAME = "domainCapabilities"
os = XMLChildProperty(_OS, is_single=True)
cpu = XMLChildProperty(_CPU, is_single=True)
devices = XMLChildProperty(_Devices, is_single=True)
features = XMLChildProperty(_Features, is_single=True)
memorybacking = XMLChildProperty(_MemoryBacking, is_single=True)
arch = XMLProperty("./arch")
domain = XMLProperty("./domain")
machine = XMLProperty("./machine")
path = XMLProperty("./path")