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 <phil@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);
>