From dbee3d02458b129b847c21f5fa60baba3eafc6f7 Mon Sep 17 00:00:00 2001
From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Tue, 12 Jun 2018 20:28:00 -0700
Subject: [PATCH] KVM: x86: VMX: fix build without hyper-v
Commit ceef7d10dfb6 ("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: ceef7d10dfb6 ("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>
---
arch/x86/kvm/vmx.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index fc61e25966e47..d0dd35d582da4 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -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;
--
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