This patch maps /domain/cpu/cache element into -cpu parameters:
- <cache mode='passthrough'/> is translated to host-cache-info=on
- <cache level='3' mode='emulate'/> is transformed into l3-cache=on
- <cache mode='disable'/> is turned in host-cache-info=off,l3-cache=off
Any other <cache> element is forbidden.
The tricky part is detecting whether QEMU supports the CPU properties.
The 'host-cache-info' property is introduced in v2.4.0-1389-ge265e3e480,
earlier QEMU releases enabled host-cache-info by default and had no way
to disable it. If the property is present, it defaults to 'off' for any
QEMU until at least 2.9.0.
The 'l3-cache' property was introduced later by v2.7.0-200-g14c985cffa.
Earlier versions worked as if l3-cache=off was passed. For any QEMU
until at least 2.9.0 l3-cache is 'off' by default.
QEMU 2.9.0 was the first release which supports probing both properties
by running device-list-properties with typename=host-x86_64-cpu. Older
QEMU releases did not support device-list-properties command for CPU
devices. Thus we can't really rely on probing them and we can just use
query-cpu-model-expansion QMP command as a witness.
Because the cache property probing is only reliable for QEMU >= 2.9.0
when both are already supported for quite a few releases, we let QEMU
report an error if a specific cache mode is explicitly requested. The
other mode (or both if a user requested CPU cache to be disabled) is
explicitly turned off for QEMU >= 2.9.0 to avoid any surprises in case
the QEMU defaults change. Any older QEMU already turns them off so not
doing so explicitly does not make any harm.
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
CPU features which change their value from disabled to enabled between
two calls to query-cpu-model-expansion (the first with no extra
properties set and the second with 'migratable' property set to false)
can be marked as enabled and non-migratable in qemuMonitorCPUModelInfo.
Since the code consuming qemuMonitorCPUModelInfo currently ignores the
migratable flag, this change is effectively changing the CPU model
advertised in domain capabilities to contain all features (even those
which block migration). And this matches what we do for QEMU older than
2.9.0, when we detect all CPUID bits ourselves without asking QEMU.
As a result of this change
<cpu mode='host-model'>
<feature name='invtsc' policy='require'/>
</cpu>
will work with all QEMU versions. Such CPU definition would be forbidden
with QEMU >= 2.9.0 without this patch.
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
If calling query-cpu-model-expansion on the 'host'/'max' CPU model with
'migratable' property set to false succeeds, we know QEMU is able to
tell us which features would disable migration. Thus we can mark all
enabled features as migratable.
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
QEMU is able to tell us whether a CPU feature would block migration or
not. This patch adds support for storing such features in
qemuMonitorCPUModelInfo.
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
The event is fired when a given block backend node (identified by the
node name) experiences a write beyond the bound set via
block-set-write-threshold QMP command. This wires up the monitor code to
extract the data and allow us receiving the events and the capability.
QEMU 2.9 introduces the pcie-root-port device, which is
a generic version of the existing ioh3420 device.
Make the new device available to libvirt users.
The static CPU model expansion is designed to return only canonical
names of all CPU properties. To maintain backwards compatibility libvirt
is stuck with different spelling of some of the features, but we need to
use the full expansion to get the additional spellings. In addition to
returning all spelling variants for all properties the full expansion
will contain properties which are not guaranteed to be migration
compatible. Thus, we need to combine both expansions. First we need to
call the static expansion to limit the result to migratable properties.
Then we can use the result of the static expansion as an input to the
full expansion to get both canonical names and their aliases.
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Querying "host" CPU model expansion only makes sense for KVM. QEMU 2.9.0
introduces a new "max" CPU model which can be used to ask QEMU what the
best CPU it can provide to a TCG domain is.
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
While query-cpu-model-expansion returns only boolean features on s390,
but x86_64 reports some integer and string properties which we are
interested in.
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Due to the extra architecture-specific logic, it's already
necessary for users to call virQEMUCapsHasPCIMultiBus(),
so the capability itself is just a pointless distraction.
QEMU 2.9.0 is not released yet but it's close to its release and
we need this data to implement new features that will be in
that release.
Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
