Re: [Qemu-devel] [PATCH] pc/fwcfg: unbreak migration from qemu-2.5 and qemu-2.6 during firmware boot

[Eduardo Habkost]

On Mon, Apr 24, 2017 at 09:56:04PM +0200, Igor Mammedov wrote:
> On Mon, 24 Apr 2017 16:37:31 -0300
> Eduardo Habkost <address@hidden> wrote:
> 
> > On Mon, Apr 24, 2017 at 09:32:33PM +0200, Igor Mammedov wrote:
> > > On Mon, 24 Apr 2017 16:13:17 -0300
> > > Eduardo Habkost <address@hidden> wrote:
> > > 
> > > > On Mon, Apr 24, 2017 at 08:58:17PM +0200, Igor Mammedov wrote:
> > > > [...]
> > > > > diff --git a/hw/i386/pc.c b/hw/i386/pc.c
> > > > > index f3b372a18f..3f2d96da64 100644
> > > > > --- a/hw/i386/pc.c
> > > > > +++ b/hw/i386/pc.c
> > > > > @@ -1047,7 +1047,7 @@ static void load_linux(PCMachineState *pcms,
> > > > >      fw_cfg_add_i32(fw_cfg, FW_CFG_SETUP_SIZE, setup_size);
> > > > >      fw_cfg_add_bytes(fw_cfg, FW_CFG_SETUP_DATA, setup, setup_size);
> > > > >  
> > > > > -    if (fw_cfg_dma_enabled(fw_cfg)) {
> > > > > +    if (!pcmc->linuxboot_dma_disabled && fw_cfg_dma_enabled(fw_cfg)) 
> > > > > {
> > > > 
> > > > Why not name the flag just "linuxboot_dma", set it to true by
> > > > default at pc_machine_class_init(), and avoid the double
> > > > negative?
> > > to avoid setting it to true somewhere else, so less thing could go wrong
> > > but is you prefer *_enable variant I can switch to it.
> > 
> > I would prefer to. We already have other compat flags initialized
> > inside pc_machine_class_init(), so this would fit nicely there.
> how about 'use_linuxboot_mmio' instead, it will remove negation
> and let me not to touch pc_machine_class_init()?

Sounds good to me.

-- 
Eduardo