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

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Commit ceef7d10df ("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: ceef7d10df ("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>
This commit is contained in:
Linus Torvalds 2018-06-12 20:28:00 -07:00
parent b08fc5277a
commit dbee3d0245
1 changed files with 3 additions and 0 deletions
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3
arch/x86/kvm/vmx.c
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@ -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;