2020-02-28 02:52:14

by Valdis Klētnieks

Subject: [PATCH] KVM: nVMX: allow compiling with W=1

Compile error with CONFIG_KVM_INTEL=y and W=1:

CC arch/x86/kvm/vmx/vmx.o
arch/x86/kvm/vmx/vmx.c:68:32: error: 'vmx_cpu_id' defined but not used [-Werror=unused-const-variable=]
68 | static const struct x86_cpu_id vmx_cpu_id[] = {
| ^~~~~~~~~~
cc1: all warnings being treated as errors

When building with =y, the MODULE_DEVICE_TABLE macro doesn't generate a
reference to the structure (or any code at all). This makes W=1 compiles
unhappy.

Wrap both in a #ifdef to avoid the issue.

Signed-off-by: Valdis Kletnieks <[email protected]>

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 40a1467d1655..5c2fc2177b0d 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -65,11 +65,13 @@
MODULE_AUTHOR("Qumranet");
MODULE_LICENSE("GPL");

+#ifdef MODULE
static const struct x86_cpu_id vmx_cpu_id[] = {
X86_FEATURE_MATCH(X86_FEATURE_VMX),
{}
};
MODULE_DEVICE_TABLE(x86cpu, vmx_cpu_id);
+#endif

bool __read_mostly enable_vpid = 1;
module_param_named(vpid, enable_vpid, bool, 0444);

2020-02-28 09:36:37

by Paolo Bonzini

Subject: Re: [PATCH] KVM: nVMX: allow compiling with W=1

On 28/02/20 03:49, Valdis Klētnieks wrote:
> Compile error with CONFIG_KVM_INTEL=y and W=1:
>
> CC arch/x86/kvm/vmx/vmx.o
> arch/x86/kvm/vmx/vmx.c:68:32: error: 'vmx_cpu_id' defined but not used [-Werror=unused-const-variable=]
> 68 | static const struct x86_cpu_id vmx_cpu_id[] = {
> | ^~~~~~~~~~
> cc1: all warnings being treated as errors
>
> When building with =y, the MODULE_DEVICE_TABLE macro doesn't generate a
> reference to the structure (or any code at all). This makes W=1 compiles
> unhappy.
>
> Wrap both in a #ifdef to avoid the issue.
>
> Signed-off-by: Valdis Kletnieks <[email protected]>
>
> diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
> index 40a1467d1655..5c2fc2177b0d 100644
> --- a/arch/x86/kvm/vmx/vmx.c
> +++ b/arch/x86/kvm/vmx/vmx.c
> @@ -65,11 +65,13 @@
> MODULE_AUTHOR("Qumranet");
> MODULE_LICENSE("GPL");
>
> +#ifdef MODULE
> static const struct x86_cpu_id vmx_cpu_id[] = {
> X86_FEATURE_MATCH(X86_FEATURE_VMX),
> {}
> };
> MODULE_DEVICE_TABLE(x86cpu, vmx_cpu_id);
> +#endif
>
> bool __read_mostly enable_vpid = 1;
> module_param_named(vpid, enable_vpid, bool, 0444);
>

Queued, and doing the same for AMD.

Paolo