From c04cfb4596ad5032a9869a8f77fe9114ca8af9e0 Mon Sep 17 00:00:00 2001 From: Daniel Hoffman Date: Sun, 19 Nov 2023 12:31:16 -0800 Subject: hw/i386: fix short-circuit logic with non-optimizing builds `kvm_enabled()` is compiled down to `0` and short-circuit logic is used to remove references to undefined symbols at the compile stage. Some build configurations with some compilers don't attempt to simplify this logic down in some cases (the pattern appears to be that the literal false must be the first term) and this was causing some builds to emit references to undefined symbols. An example of such a configuration is clang 16.0.6 with the following configure: ./configure --enable-debug --without-default-features --target-list=x86_64-softmmu --enable-tcg-interpreter Signed-off-by: Daniel Hoffman Message-Id: <20231119203116.3027230-1-dhoff749@gmail.com> Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin --- hw/i386/x86.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) diff --git a/hw/i386/x86.c b/hw/i386/x86.c index b3d054889b..2b6291ad8d 100644 --- a/hw/i386/x86.c +++ b/hw/i386/x86.c @@ -131,8 +131,12 @@ void x86_cpus_init(X86MachineState *x86ms, int default_cpu_version) /* * Can we support APIC ID 255 or higher? With KVM, that requires * both in-kernel lapic and X2APIC userspace API. + * + * kvm_enabled() must go first to ensure that kvm_* references are + * not emitted for the linker to consume (kvm_enabled() is + * a literal `0` in configurations where kvm_* aren't defined) */ - if (x86ms->apic_id_limit > 255 && kvm_enabled() && + if (kvm_enabled() && x86ms->apic_id_limit > 255 && (!kvm_irqchip_in_kernel() || !kvm_enable_x2apic())) { error_report("current -smp configuration requires kernel " "irqchip and X2APIC API support."); @@ -418,8 +422,13 @@ void x86_cpu_pre_plug(HotplugHandler *hotplug_dev, } cpu->thread_id = topo_ids.smt_id; - if (hyperv_feat_enabled(cpu, HYPERV_FEAT_VPINDEX) && - kvm_enabled() && !kvm_hv_vpindex_settable()) { + /* + * kvm_enabled() must go first to ensure that kvm_* references are + * not emitted for the linker to consume (kvm_enabled() is + * a literal `0` in configurations where kvm_* aren't defined) + */ + if (kvm_enabled() && hyperv_feat_enabled(cpu, HYPERV_FEAT_VPINDEX) && + !kvm_hv_vpindex_settable()) { error_setg(errp, "kernel doesn't allow setting HyperV VP_INDEX"); return; } -- cgit v1.2.3