Re: [libvirt] [Qemu-devel] [PATCH qom-cpu 10/11] target-i386: Call kvm_check_features_against_host() only if CONFIG_KVM is set

On Mon, 7 Jan 2013 10:00:09 -0200 Eduardo Habkost <ehabkost(a)redhat.com&gt; wrote: > On Sun, Jan 06, 2013 at 04:27:19PM +0200, Gleb Natapov wrote: > > On Fri, Jan 04, 2013 at 08:01:11PM -0200, Eduardo Habkost wrote: > > > This will be necessary once kvm_check_features_against_host() starts > > > using KVM-specific definitions (so it won't compile anymore if > > > CONFIG_KVM is not set). > > > > > > Signed-off-by: Eduardo Habkost <ehabkost(a)redhat.com&gt; > > > --- > > > target-i386/cpu.c | 4 ++++ > > > 1 file changed, 4 insertions(+) > > > > > > diff --git a/target-i386/cpu.c b/target-i386/cpu.c > > > index 1c3c7e1..876b0f6 100644 > > > --- a/target-i386/cpu.c > > > +++ b/target-i386/cpu.c > > > @@ -936,6 +936,7 @@ static void kvm_cpu_fill_host(x86_def_t *x86_cpu_def) > > > #endif /* CONFIG_KVM */ > > > } > > > > > > +#ifdef CONFIG_KVM > > > static int unavailable_host_feature(struct model_features_t *f, uint32_t mask) > > > { > > > int i; > > > @@ -987,6 +988,7 @@ static int kvm_check_features_against_host(x86_def_t *guest_def) > > > } > > > return rv; > > > } > > > +#endif > > > > > > static void x86_cpuid_version_get_family(Object *obj, Visitor *v, void *opaque, > > > const char *name, Error **errp) > > > @@ -1410,10 +1412,12 @@ static int cpu_x86_parse_featurestr(x86_def_t *x86_cpu_def, char *features) > > > x86_cpu_def->kvm_features &= ~minus_kvm_features; > > > x86_cpu_def->svm_features &= ~minus_svm_features; > > > x86_cpu_def->cpuid_7_0_ebx_features &= ~minus_7_0_ebx_features; > > > +#ifdef CONFIG_KVM > > > if (check_cpuid && kvm_enabled()) { > > > if (kvm_check_features_against_host(x86_cpu_def) && enforce_cpuid) > > > goto error; > > > } > > > +#endif > > Provide kvm_check_features_against_host() stub if !CONFIG_KVM and drop > > ifdef here. > > I will do. Igor probably will have to change his "target-i386: move > kvm_check_features_against_host() check to realize time" patch to use > the same approach, too. Gleb, Why do stub here? As result we will be adding more ifdef-s just in other places. Currently kvm_cpu_fill_host(), unavailable_host_feature() and

kvm_check_features_against_host() are bundled together in cpu.c so we could instead ifdef whole block. Like here: http://www.mail-archive.com/qemu-devel@nongnu.org/msg146536.html

For me code looks more readable with ifdef here, if we have stub, a reader would have to look at kvm_check_features_against_host() body to see if it does anything.