The query-cpu-model-expand QMP command needs at least one static
model, to allow the "static" expansion mode to be implemented.
Instead of defining static versions of every CPU model, define a
"base" CPU model that has absolutely no feature flag enabled.
Despite having no CPUID data set at all, "-cpu base" is even a
functional CPU:
* It can boot a Slackware Linux 1.01 image with a Linux 0.99.12
kernel[1].
* It is even possible to boot[2] a modern Fedora x86_64 guest by
manually enabling the following CPU features:
-cpu base,+lm,+msr,+pae,+fpu,+cx8,+cmov,+sse,+sse2,+fxsr
[1] http://www.qemu-advent-calendar.org/2014/#day-1
[2] This is what can be seen in the guest:
[root@localhost ~]# cat /proc/cpuinfo
processor : 0
vendor_id : unknown
cpu family : 0
model : 0
model name : 00/00
stepping : 0
physical id : 0
siblings : 1
core id : 0
cpu cores : 1
apicid : 0
initial apicid : 0
fpu : yes
fpu_exception : yes
cpuid level : 1
wp : yes
flags : fpu msr pae cx8 cmov fxsr sse sse2 lm nopl
bugs :
bogomips : 5832.70
clflush size : 64
cache_alignment : 64
address sizes : 36 bits physical, 48 bits virtual
power management:
[root@localhost ~]# x86info -v -a
x86info v1.30. Dave Jones 2001-2011
Feedback to <davej@redhat.com>.
No TSC, MHz calculation cannot be performed.
Unknown vendor (0)
MP Table:
Family: 0 Model: 0 Stepping: 0
CPU Model (x86info's best guess):
eax in: 0x00000000, eax = 00000001 ebx = 00000000 ecx = 00000000 edx = 00000000
eax in: 0x00000001, eax = 00000000 ebx = 00000800 ecx = 00000000 edx = 07008161
eax in: 0x80000000, eax = 80000001 ebx = 00000000 ecx = 00000000 edx = 00000000
eax in: 0x80000001, eax = 00000000 ebx = 00000000 ecx = 00000000 edx = 20000000
Feature flags:
fpu Onboard FPU
msr Model-Specific Registers
pae Physical Address Extensions
cx8 CMPXCHG8 instruction
cmov CMOV instruction
fxsr FXSAVE and FXRSTOR instructions
sse SSE support
sse2 SSE2 support
Long NOPs supported: yes
Address sizes : 0 bits physical, 0 bits virtual
0MHz processor (estimate).
running at an estimated 0MHz
[root@localhost ~]#
Message-Id: <20170222190029.17243-2-ehabkost@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Tested-by: Jiri Denemark <jdenemar@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
5adbed3088