When starting a domain without a CPU model specified in the domain XML,
QEMU will choose a default one. Which is fine unless the domain gets
migrated to another host because libvirt doesn't perform any CPU ABI
checks and the virtual CPU provided by QEMU on the destination host can
differ from the one on the source host.
With QEMU 4.2.0 we can probe for the default CPU model used by QEMU for
a particular machine type and store it in the domain XML. This way the
chosen CPU model is more visible to users and libvirt will make sure
the guest will see the exact same CPU after migration.
Architecture specific notes
- aarch64: We only set the default CPU for TCG domains as KVM requires
explicit "-cpu host" to work.
- ppc64: The default CPU for KVM is "host" thanks to some hacks in QEMU,
we will translate the default model to the model corresponding to the
host CPU ("POWER8" on a Power8 host, "POWER9" on Power9 host, etc.).
This is not a problem as the corresponding CPU model is in fact an
alias for "host". This is probably not ideal, but it's not wrong and
the default virtual CPU configured by libvirt is the same QEMU would
use. TCG uses various CPU models depending on machine type and its
version.
- s390x: The default CPU for KVM is "host" while TCG defaults to "qemu".
- x86_64: The default CPU model (qemu64) is not runnable on any host
with KVM, but QEMU just disables unavailable features and starts
happily.
https://bugzilla.redhat.com/show_bug.cgi?id=1598151https://bugzilla.redhat.com/show_bug.cgi?id=1598162
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
QEMU 4.2.0 will report default CPU types used by each machine type and
we will want to start using it.
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Almost all TCG query-machines replies match KVM. The only exceptions are
4.2.0 replies on s390x which differ in the reported default CPU type.
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Some specifics of machine types may depend on the accelerator and thus
the data should be moved to virQEMUCapsAccel. The TCG machine types are
just copied from the ones probed for KVM to simplify the changes to
qemucapabilitiestest data files.
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
The function copies machine type data from one QEMU caps structure to
another.
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
In preparation for making machine types dependent on the accelerator,
the <machine> elements are formatted between <cpu type='kvm'> and
<cpu type='tcg'>.
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
All the code for formatting machine type data was moved to a standalone
virQEMUCapsFormatMachines function.
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
All the code for loading machine type data was moved to a standalone
virQEMUCapsLoadMachines function.
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
To avoid duplicating code which selects the right virQEMUCapsAccel data
to be filled during probing.
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
It is a tiny wrapper around virQEMUCapsProbeQMPCPUDefinitions which will
soon get private parameters and thus it cannot be exposed outside
qemu_capabilities.
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
And make it use virQEMUCapsGetAccel once rather than repeating the same
code in all functions called from virQEMUCapsFormatAccel.
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
And make it use virQEMUCapsGetAccel once rather than repeating the same
code in all functions called from virQEMUCapsLoadAccel.
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
The function can be used to get the pointer to all data which depend on
the accelerator.
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
This is container for capabilities data that depend on the accelerator.
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
The new functions are designed to load and format capabilities which
depend on the accelerator (host CPU expansion and CPU models).
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
We need to create a mapping between CPU model names and their
corresponding QOM types.
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Both virDomainCapsCPUModelsAdd and virDomainCapsCPUModelsAddSteal are so
simple we can just squash the code in a single function.
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
We will need to keep some QEMU-specific data for each CPU model
supported by a QEMU binary. Instead of complicating the generic
virDomainCapsCPUModelsPtr, we can just directly store
qemuMonitorCPUDefsPtr returned by the capabilities probing code.
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Most of the code moved to a new virQEMUCapsFetchCPUDefinitions function
and the existing virQEMUCapsFetchCPUModels just becomes a small wrapper
around virQEMUCapsFetchCPUDefinitions and virQEMUCapsCPUDefsToModels.
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
The functions return virDomainCapsCPUModelsPtr and thus they should be
called *CPUModels for consistency. Functions called *CPUDefinitions will
work on qemuMonitorCPUDefsPtr.
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
The function translates qemuMonitorCPUDefsPtr (used by QEMU caps probing
code) into virDomainCapsCPUModelsPtr used by domain capabilities.
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
While virDomainCapsCPUModel structure contains 'usable' field with
virDomainCapsCPUUsable type, the lower level structure specific to QEMU
driver used virTriStateBool for the same thing and we had to translate
between them.
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Let's store qemuMonitorCPUDefInfo directly in the array of CPUs in
qemuMonitorCPUDefs rather then using an array of pointers.
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
It is a container for a CPU models list (qemuMonitorCPUDefInfo) and a
number of elements in this list.
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
The function would return a valid virDomainCapsCPUModelsPtr with empty
CPU models list if query-cpu-definitions exists in QEMU, but returns
GenericError meaning it's not in fact implemented. This behaviour is a
bit strange especially after such virDomainCapsCPUModels structure is
stored in capabilities XML and parsed back, which will result in NULL
virDomainCapsCPUModelsPtr rather than a structure containing nothing.
Let's just keep virDomainCapsCPUModelsPtr NULL if the QMP command is not
implemented and change the return value to int so that callers can
easily check for failure or success.
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Some callers of virQEMUCapsGetCPUDefinitions will need to filter the
returned list of CPU models. Let's add the filtering parameters directly
to virQEMUCapsGetCPUDefinitions to avoid copying the CPU models list
twice.
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Rather than returning a direct pointer the list stored in qemuCaps the
function now creates a new copy of the CPU models list.
The main purpose of this seemingly useless change is to update callers
to free the result returned by virQEMUCapsGetCPUDefinitions because the
internals of this function will change significantly in the following
patches.
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Generated with "spapr/kvm: Set default cpu model for all machine
classes" fix for QEMU applied.
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
