Re: [Qemu-devel] [PATCH v3] virtio-mmio: implement modern (v2), personality (virtio-1)

[Vasyl Vavrychuk <vvavrychuk@gmail.com>]

Hi, Sergio,

 > For this reason, the v2 personality is disabled, keeping the legacy
 > behavior as default. Machine types willing to use v2, can enable it
 > using MachineClass's compat_props.
...
 > +    DEFINE_PROP_BOOL("force-legacy", VirtIOMMIOProxy, legacy, true),

Currently, I am not enable to set "force-legacy" to false from command 
line for
virt machine.

I think, the "force-legacy" and compat_props should work the other way 
around.

The "force-legacy" should be set to false by default to select a new 
behaviour.
Instead of this hw_compat_4_1 should be modified to keep the old behaviour:

--- a/hw/core/machine.c
+++ b/hw/core/machine.c
@@ -29,6 +29,7 @@

  GlobalProperty hw_compat_4_1[] = {
      { "virtio-pci", "x-pcie-flr-init", "off" },
+    { "virtio-mmio", "force-legacy", "on" },
  };
  const size_t hw_compat_4_1_len = G_N_ELEMENTS(hw_compat_4_1);


This way, one can keep the old behaviour by doing "-M virt-4.1"

Best regards,
Vasyl