On Wed 13. Nov 2024 at 19:06, Paolo Bonzini <pbonz...@redhat.com> wrote:
> On 11/13/24 15:49, Phil Dennis-Jordan wrote: > > It appears that existing call sites for the kvm_enable_x2apic() > > function rely on the compiler eliding the calls during optimisation > > when building with KVM disabled, or on platforms other than Linux, > > where that function is declared but not defined. > > > > This fragile reliance recently broke down when commit b12cb38 added > > a new call site which apparently failed to be optimised away when > > building QEMU on macOS with clang, resulting in a link error. > > That's weird, can you check the preprocessor output? The definition > of kvm_irqchip_in_kernel() should be just "false" on macOS, in fact > even the area you're changing should be simplified like > Yeah, to be honest this header file seems a bit of a mess. It’s being #included by a bunch of .c files in hw/ despite being located in target/ not include/ which suggests to me that some of the declarations ought to be moved. As I’m not really familiar with any of the KVM code base I would not normally be attempting to clean this up but the staging & master branches currently don’t build on macOS, so I was aiming for the simplest fix possible for the immediate problem. (I will test your patch shortly however.) > diff --git a/target/i386/kvm/kvm_i386.h b/target/i386/kvm/kvm_i386.h > index 9de9c0d3038..7edb154a16e 100644 > --- a/target/i386/kvm/kvm_i386.h > +++ b/target/i386/kvm/kvm_i386.h > @@ -13,8 +13,7 @@ > > #include "sysemu/kvm.h" > > -#ifdef CONFIG_KVM > - > +/* always false if !CONFIG_KVM */ > #define kvm_pit_in_kernel() \ > (kvm_irqchip_in_kernel() && !kvm_irqchip_is_split()) > #define kvm_pic_in_kernel() \ > @@ -22,14 +21,6 @@ > #define kvm_ioapic_in_kernel() \ > (kvm_irqchip_in_kernel() && !kvm_irqchip_is_split()) > > -#else > - > -#define kvm_pit_in_kernel() 0 > -#define kvm_pic_in_kernel() 0 > -#define kvm_ioapic_in_kernel() 0 > - > -#endif /* CONFIG_KVM */ > - > bool kvm_has_smm(void); > bool kvm_enable_x2apic(void); > > Paolo > > > > > Signed-off-by: Phil Dennis-Jordan <p...@philjordan.eu> > > --- > > target/i386/kvm/kvm_i386.h | 3 ++- > > 1 file changed, 2 insertions(+), 1 deletion(-) > > > > diff --git a/target/i386/kvm/kvm_i386.h b/target/i386/kvm/kvm_i386.h > > index 9de9c0d3038..7ce47388d90 100644 > > --- a/target/i386/kvm/kvm_i386.h > > +++ b/target/i386/kvm/kvm_i386.h > > @@ -21,17 +21,18 @@ > > (kvm_irqchip_in_kernel() && !kvm_irqchip_is_split()) > > #define kvm_ioapic_in_kernel() \ > > (kvm_irqchip_in_kernel() && !kvm_irqchip_is_split()) > > +bool kvm_enable_x2apic(void); > > > > #else > > > > #define kvm_pit_in_kernel() 0 > > #define kvm_pic_in_kernel() 0 > > #define kvm_ioapic_in_kernel() 0 > > +#define kvm_enable_x2apic() 0 > > > > #endif /* CONFIG_KVM */ > > > > bool kvm_has_smm(void); > > -bool kvm_enable_x2apic(void); > > bool kvm_hv_vpindex_settable(void); > > bool kvm_enable_hypercall(uint64_t enable_mask); > > > >
