Changes v2 -> v3;
- Check for kvm_enabled() before setting cpuid_7_0_ebx_features
Changes v1 -> v2:
- Use kvm_arch_get_supported_cpuid() instead of host_cpuid() on
cpu_x86_fill_host().
We should use GET_SUPPORTED_CPUID for all bits on "-cpu host"
eventually, but I am not changing all the other CPUID leaves because
we may not be able to test such an intrusive change in time for 1.1.
Description of the bug:
Since QEMU 0.15, the CPUID information on CPUID[EAX=7,ECX=0] is being
returned unfiltered to the guest, directly from the GET_SUPPORTED_CPUID
return value.
The problem is that this makes the resulting CPU feature flags
unpredictable and dependent on the host CPU and kernel version. This
breaks live-migration badly if migrating from a host CPU that supports
some features on that CPUID leaf (running a recent kernel) to a kernel
or host CPU that doesn't support it.
Migration also is incorrect (the virtual CPU changes under the guest's
feet) if you migrate in the opposite direction (from an old CPU/kernel
to a new CPU/kernel), but with less serious consequences (guests
normally query CPUID information only once on boot).
Fortunately, the bug affects only users using cpudefs with level >= 7.
The right behavior should be to explicitly enable those features on
[cpudef] config sections or on the "-cpu" command-line arguments. Right
now there is no predefined CPU model on QEMU that has those features:
the latest Intel model we have is Sandy Bridge.
I would like to get this fixed on 1.1, so I am submitting this patch,
that enables those features only if "-cpu host" is being used (as we
don't have any pre-defined CPU model that actually have those features).
After 1.1 is released, we can make those features properly configurable
on [cpudef] and -cpu configuration.
One problem is: with this patch, users with the following setup:
- Running QEMU 1.0;
- Using a cpudef having level >= 7;
- Running a kernel that supports the features on CPUID leaf 7; and
- Running on a CPU that supports some features on CPUID leaf 7
won't be able to live-migrate to QEMU 1.1. But for these users
live-migration is already broken (they can't live-migrate to hosts with
older CPUs or older kernels, already), I don't see how to avoid this
problem.
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Commit de024815e3 (target-i386: QOM'ify
CPU init) moved mce_init() call from helper.c:cpu_x86_init() into
X86CPU's cpu.c:x86_cpu_initfn().
mce_init() checks for a family >= 6 though, so we could end up with a
sequence such as for -cpu somecpu,family=6:
x86_cpu_initfn => X86CPU::family == 5
mce_init => no-op
cpu_x86_register => X86CPU::family = 6
=> MCE unexpectedly not init'ed
or for -cpu someothercpu,family=5:
x86_cpu_initfn => X86CPU::family == 6
mce_init => init'ed
cpu_x86_register => X86CPU::family = 5
=> MCE unexpectedly init'ed
Therefore partially revert the above commit. To avoid moving
mce_init() back into helper.c, foresightedly move it into a
new x86_cpu_realize() function and, in lack of ObjectClass::realize,
call it directly from cpu_x86_init().
While at it, move the qemu_init_vcpu() call that used to follow
mce_init() in cpu_x86_init() into the new realizefn as well.
Reported-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Use Hz as unit.
Signed-off-by: Andreas Färber <afaerber@suse.de>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Using it now would incur converting the three x86_def_t vendor words
into a string for object_property_set_str(), then back to three words
in the "vendor" setter.
The built-in CPU definitions use numeric preprocessor defines to
initialize the three words in a charset-safe way, so do not change the
fields to char[12] just to use the setter.
Signed-off-by: Andreas Färber <afaerber@suse.de>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Add the property early in the initfn so that it can be used in helpers
such as mce_init().
Signed-off-by: Andreas Färber <afaerber@suse.de>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
[AF: Add an error_free(), spotted by Michael Roth]
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
A family field value of 0xf and extended family field value of 0xff is
the maximum representable unsigned family number.
All other CPUID property values are bounds-checked, so add a check here
for symmetry before we adopt it in a property setter.
Signed-off-by: Andreas Färber <afaerber@suse.de>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Avoids an x86_env_get_cpu() call there, to work with QOM properties.
Signed-off-by: Andreas Färber <afaerber@suse.de>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Don't assume zeroed cpuid_model[] fields.
This didn't break anything yet but QOM properties should be able to set
the value to something else without setting an intermediate zero string.
Reviewed-by: Eduardo Habhost <ehabkost@redhat.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
[AF: Use memset() instead of for loop, suggested by Igor]
Signed-off-by: Andreas Färber <afaerber@suse.de>
Move code from cpu_x86_init() to new QOM x86_cpu_initfn().
Also move mce_init() to cpu.c since it's used nowhere else.
Signed-off-by: Andreas Färber <afaerber@suse.de>
Embed CPUX86State as first member of X86CPU.
Distinguish between "x86_64-cpu" and "i386-cpu".
Drop cpu_x86_close() in favor of calling object_delete() directly.
For now let CPUClass::reset() call cpu_state_reset().
Signed-off-by: Andreas Färber <afaerber@suse.de>
