On 10/07/2014 03:58 PM, Paolo Bonzini wrote:
Il 07/10/2014 21:44, Wei Huang ha scritto:
AMD CPU doesn't support hyperthreading. Even though QEMU fixes
this issue by setting CPUID_0000_0001_EBX and CPUID_8000_0008_ECX
via conversion, it is better to stop end-users in the first place
with a warning message.
Hi Wei,
what exactly breaks if you try creating an AMD VM with hyperthreading?
Hi Paolo,
It isn't a bug IMO. I tested various combinations; and current QEMU
handles it very well. It converts threads=n to proper
CPUID_0000_0001_EBX[LogicalProcCount] and CPUID_8000_0008_ECX[NC]
accordingly for AMD.
There is a bugzilla reported for such configuration:
https://bugzilla.redhat.com/show_bug.cgi?id=1135772. So I thought such
checking might be a good thing to do.
I am worried that the default CPU is an AMD one when KVM is disabled,
and thus "qemu-system-x86_64 -smp threads=2" will likely be broken.
"-smp threads=2" will be rejected by the patch. Unless the meaning of
threads is not limited to threads-per-core, shouldn't end users use
"-smp 2" in this case or something like "-smp 2,cores=2,sockets=1"?
Paolo
