| Message ID | 20180525153640.3228067-1-arnd@arndb.de |
|---|---|
| State | New |
| Headers | show |
| Series | KVM: x86: VMX: fix building without CONFIG_HYPERV | expand |
Arnd Bergmann <arnd@arndb.de> writes: > The global ms_hyperv variable is part of the hyperv support, so > we get a link error from accessing it in kernels that have this > turned off: > > arch/x86/kvm/vmx.o: In function `alloc_loaded_vmcs': > vmx.c:(.text+0x1654a): undefined reference to `ms_hyperv' > vmx.c:(.text+0x1657a): undefined reference to `ms_hyperv' > > This changes the condition to first check the compile-time > configuration symbol to avoid the link error. > > Fixes: ceef7d10dfb6 ("KVM: x86: VMX: hyper-v: Enlightened MSR-Bitmap support") > Signed-off-by: Arnd Bergmann <arnd@arndb.de> Thanks, Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com> (I don't really like this IS_ENABLED(CONFIG_HYPERV) spreading across KVM but keeping stuff like this ms_hyperv structure defined when !IS_ENABLED(CONFIG_HYPERV) is also ugly. It may make sense to define helpers similar to kvm_para_has_feature() and define them to 'false' when Hyper-V support code is compiled out. I'll look into this option later, this patch should be taken to fix the immediate issue). > --- > arch/x86/kvm/vmx.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c > index ea098131dcce..e6d6ccab43c3 100644 > --- a/arch/x86/kvm/vmx.c > +++ b/arch/x86/kvm/vmx.c > @@ -4232,7 +4232,8 @@ static int alloc_loaded_vmcs(struct loaded_vmcs *loaded_vmcs) > goto out_vmcs; > memset(loaded_vmcs->msr_bitmap, 0xff, PAGE_SIZE); > > - if (static_branch_unlikely(&enable_evmcs) && > + if (IS_ENABLED(CONFIG_HYPERV) && > + static_branch_unlikely(&enable_evmcs) && > (ms_hyperv.nested_features & HV_X64_NESTED_MSR_BITMAP)) { > struct hv_enlightened_vmcs *evmcs = > (struct hv_enlightened_vmcs *)loaded_vmcs->vmcs; -- Vitaly
2018-05-25 17:36+0200, Arnd Bergmann: > The global ms_hyperv variable is part of the hyperv support, so > we get a link error from accessing it in kernels that have this > turned off: > > arch/x86/kvm/vmx.o: In function `alloc_loaded_vmcs': > vmx.c:(.text+0x1654a): undefined reference to `ms_hyperv' > vmx.c:(.text+0x1657a): undefined reference to `ms_hyperv' > > This changes the condition to first check the compile-time > configuration symbol to avoid the link error. > > Fixes: ceef7d10dfb6 ("KVM: x86: VMX: hyper-v: Enlightened MSR-Bitmap support") > Signed-off-by: Arnd Bergmann <arnd@arndb.de> Queued, thanks.
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index ea098131dcce..e6d6ccab43c3 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -4232,7 +4232,8 @@ static int alloc_loaded_vmcs(struct loaded_vmcs *loaded_vmcs) goto out_vmcs; memset(loaded_vmcs->msr_bitmap, 0xff, PAGE_SIZE); - if (static_branch_unlikely(&enable_evmcs) && + if (IS_ENABLED(CONFIG_HYPERV) && + static_branch_unlikely(&enable_evmcs) && (ms_hyperv.nested_features & HV_X64_NESTED_MSR_BITMAP)) { struct hv_enlightened_vmcs *evmcs = (struct hv_enlightened_vmcs *)loaded_vmcs->vmcs;
The global ms_hyperv variable is part of the hyperv support, so we get a link error from accessing it in kernels that have this turned off: arch/x86/kvm/vmx.o: In function `alloc_loaded_vmcs': vmx.c:(.text+0x1654a): undefined reference to `ms_hyperv' vmx.c:(.text+0x1657a): undefined reference to `ms_hyperv' This changes the condition to first check the compile-time configuration symbol to avoid the link error. Fixes: ceef7d10dfb6 ("KVM: x86: VMX: hyper-v: Enlightened MSR-Bitmap support") Signed-off-by: Arnd Bergmann <arnd@arndb.de> --- arch/x86/kvm/vmx.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) -- 2.9.0