On Mon, Aug 19, 2013 at 09:04:28AM -0300, Eduardo Habkost wrote:
> On Sun, Aug 18, 2013 at 04:50:02PM +0300, Michael S. Tsirkin wrote:
> > Make 1.4 compat code call the 1.6 one, reducing
> > code duplication. Add comment explaining why we can't
> > make 1.4 call 1.5 as usual.
> >
> > Signed-off-by: Michael S. Tsirkin <m...@redhat.com>
> > ---
> > hw/i386/pc_piix.c | 4 ++--
> > hw/i386/pc_q35.c | 4 ++--
> > 2 files changed, 4 insertions(+), 4 deletions(-)
> >
> > diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
> > index 15c932e..86cfadc 100644
> > --- a/hw/i386/pc_piix.c
> > +++ b/hw/i386/pc_piix.c
> > @@ -272,8 +272,8 @@ static void pc_init_pci_1_4(QEMUMachineInitArgs *args)
> > {
> > x86_cpu_compat_set_features("n270", FEAT_1_ECX, 0, CPUID_EXT_MOVBE);
> > x86_cpu_compat_set_features("Westmere", FEAT_1_ECX, 0,
> > CPUID_EXT_PCLMULQDQ);
> > - has_pci_info = false;
> > - pc_init_pci(args);
> > + /* 1.5 was special - it enabled pvpanic in builtin machine */
> > + pc_init_pci_1_6(args);
> > }
> >
>
> I find this confusing (and probably it will be even more confusing when
> people read this code a few years from now). I would prefer the
> following pattern:
>
> static void pc_compat_1_5()
> {
> /* do 1.5 stuff (possibly undoing 1.6 stuff) */
> has_pvpanic = true;
> }
>
> static void pc_init_pci_1_5()
> {
> pc_compat_1_5();
> pc_init_pci();
> }
>
> static void pc_compat_1_4()
> {
> pc_compat_1_5();
> /* do 1.4 stuff (possibly undoing 1.5 stuff) */
> has_pvpanic = false;
> }
>
> static void pc_init_pci_1_4()
> {
> pc_compat_1_4();
> pc_init_pci();
> }
>
> static void pc_compat_1_3()
> {
> pc_compat_1_3();
> /* do 1.3 stuff (possibly undoing 1.4 stuff) */
> }
>
> static void pc_init_pci_1_3()
> {
> pc_compat_1_3();
> pc_init_pci();
> }
>
> Otherwise the same problem may happen again in the future.
Sure, why not. Want to send a patch like this?
Prefer a patch on top of this one, or instead of it?
>
> With this, we could even reuse the same pc_compat_*() functions on
> pc_piix.c and pc_q35.c.
That would be nice.
> > static void pc_init_pci_1_3(QEMUMachineInitArgs *args)
> > diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c
> > index 09d8183..8d62700 100644
> > --- a/hw/i386/pc_q35.c
> > +++ b/hw/i386/pc_q35.c
> > @@ -239,8 +239,8 @@ static void pc_q35_init_1_4(QEMUMachineInitArgs *args)
> > {
> > x86_cpu_compat_set_features("n270", FEAT_1_ECX, 0, CPUID_EXT_MOVBE);
> > x86_cpu_compat_set_features("Westmere", FEAT_1_ECX, 0,
> > CPUID_EXT_PCLMULQDQ);
> > - has_pci_info = false;
> > - pc_q35_init(args);
> > + /* 1.5 was special - it enabled pvpanic in builtin machine */
> > + pc_q35_init_1_6(args);
> > }
> >
> > static QEMUMachine pc_q35_machine_v1_6 = {
> > --
> > MST
>
> --
> Eduardo
