Re: [libvirt] kvm: "warning: host doesn't support requested feature: CPUID.01H:ECX.x2apic [bit 21]"
(CCing libvir-list)
On Sat, Feb 20, 2016 at 04:00:30AM -0500, Paolo Bonzini wrote:
----- Original Message -----
> From: "Jan Kiszka" <jan.kiszka(a)web.de>
> To: "Eduardo Habkost" <ehabkost(a)redhat.com>, "Paolo
Bonzini" <pbonzini(a)redhat.com>
> Cc: "qemu-devel" <qemu-devel(a)nongnu.org>, "kvm"
<kvm(a)vger.kernel.org>
> Sent: Saturday, February 20, 2016 9:09:32 AM
> Subject: kvm: "warning: host doesn't support requested feature:
CPUID.01H:ECX.x2apic [bit 21]"
>
> Hi all,
>
> I suppose 5120901a37 introduced this: qemu with kernel_irqchip=off now
> generates these warnings, one per VCPU, during QEMU startup. Is the plan
> to live with them until we finally have x2APIC emulation in userspace
> (ie. also MSR vmexiting to there), or should we otherwise avoid it?
I think it's a bug, x2apic should be auto-suppressed with kernel_irqchip=off.
My first reaction is to dislike the idea of adding yet another
variable that affects the results of CPU models.
But considering that we are moving towards a design where libvirt
must not assume or query any low-level detail from CPU models at
all, maybe this won't be harmful.
--
Eduardo