Commit dbee3d02 authored Jun 12, 2018 by Linus Torvalds

KVM: x86: VMX: fix build without hyper-v



Commit ceef7d10 ("KVM: x86: VMX: hyper-v: Enlightened MSR-Bitmap
support") broke the build with Hyper-V disabled, because it accesses
ms_hyperv.nested_features without checking if that exists.

This is the quick-and-hacky build fix.

I suspect the proper fix is to replace the

    static_branch_unlikely(&enable_evmcs)

tests with an inline helper function that also checks that CONFIG_HYPERV
is enabled, since without that, enable_evmcs makes no sense.

But I want a working build environment first and foremost, and I'm upset
this slipped through in the first place.  My primary build tests missed
it because I tend to build with everything enabled, but it should have
been caught in the kvm tree.

Fixes: ceef7d10 ("KVM: x86: VMX: hyper-v: Enlightened MSR-Bitmap support")
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent b08fc527

arch/x86/kvm/vmx.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -4429,6 +4429,7 @@ static int alloc_loaded_vmcs(struct loaded_vmcs *loaded_vmcs)
		goto out_vmcs;
		memset(loaded_vmcs->msr_bitmap, 0xff, PAGE_SIZE);

		#if IS_ENABLED(CONFIG_HYPERV)
		if (static_branch_unlikely(&enable_evmcs) &&
		(ms_hyperv.nested_features & HV_X64_NESTED_MSR_BITMAP)) {
		struct hv_enlightened_vmcs *evmcs =
		@@ -4436,6 +4437,8 @@ static int alloc_loaded_vmcs(struct loaded_vmcs *loaded_vmcs)

		evmcs->hv_enlightenments_control.msr_bitmap = 1;
		}
		#endif

		}
		return 0;