Re: [PATCH] target/i386: add VMX features to named CPU models

[Kashyap Chamarthy <kchamart@redhat.com>]

On Wed, Nov 20, 2019 at 06:57:20PM +0100, Paolo Bonzini wrote:
> On 20/11/19 18:50, Daniel P. Berrangé wrote:
> > On Wed, Nov 20, 2019 at 06:37:53PM +0100, Paolo Bonzini wrote:
> >> This allows using "-cpu Haswell,+vmx", which we did not really want to
> >> support in QEMU but was produced by Libvirt when using the "host-model"
> >> CPU model.
> > Can you say what is currently broken ?  If I launch my current QEMU (I have
> > 4.1.1 on Fedora 31):
> > 
> >  qemu-system-x86_64 -cpu Haswell,+vmx
> > 
> > ... I don't get any reported errors.
> > 
> 
> KVM does not load in the guest, though?

Indeed it doesn't:

    $> ./min-qemu.sh
    qemu-system-x86_64: warning: host doesn't support requested feature: CPUID.01H:ECX.vmx [bit 5]

    [...]
    cirros login: cirros
    Password: 
    [cirros] $ cat /proc/cpuinfo | grep vmx
    [cirros] $ echo $?
    1

Where `cat min-qemu.sh` is:
------------------------------------------------------------------------
#!/usr/bin/env bash

args=(
 -display none
 -cpu Haswell,+vmx
 -no-user-config
 -machine q35,accel=kvm
 -nodefaults
 -m 2048
 -serial stdio
 -drive file=/export/vm1.qcow2,format=qcow2,if=virtio
)

~/build/qemu/x86_64-softmmu/qemu-system-x86_64 "${args[@]}"
------------------------------------------------------------------------

[...]

-- 
/kashyap