Brian Jackson wrote:
On Thursday 03 June 2010 21:33:24 Govender, Sashan wrote:
Hi
We bumped into this issue with VMWare ESX 4 where it doesn't support
hardware virtualization if the processor is an AMD Athlon/Opteron
(http://communities.vmware.com/docs/DOC-9150). Does linux-kvm have a
similar issue? More specifically will the the module kvm_amd.ko support
AMD-V on an Opteron 2218?
Yes, KVM doesn't try to be too smart. If you have svm/vt, it runs. If you
don't, it falls back to tcg (qemu's normal/slow mode). The kvm-amd module will
load as long as the bios and the CPU both support and enable svm.
That's right. Please note that KVM depends on hardware virtualization,
so it does not have the choice like VMware has. Falling back to QEMU/TCG
is not comparable to VMware's binary translation, because their approach
is highly optimized and limited to x86 on x86, whereas QEMU wants to
emulate each supported architecture on each host architecture, so it
naturally cannot be as sophisticated as the VMware approach.
Nested paging has been supported by KVM for a long time, if it's there
it will be automatically used.
BTW, every Opteron with a four-digit number supports AMD-V, and KVM will
run on every such processor. I am not aware of any _Opteron_ boards not
allowing AMD-V, but there are some desktop/notebook systems where the
BIOS denies AMD-V (although the processor has it).
There presence of the "svm" flag in /proc/cpuinfo is a safe indicator
for the usability of KVM.
Regards,
Andre.
--
Andre Przywara
AMD-Operating System Research Center (OSRC), Dresden, Germany
Tel: +49 351 448-3567-12
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