[PATCH v2 2/3] KVM: x86: Add a VALID_MASK for the flags in kvm_msr_filter_range

[Aaron Lewis <aaronlewis@google.com>]

Add the mask KVM_MSR_FILTER_RANGE_VALID_MASK for the flags in the
struct kvm_msr_filter_range.  This simplifies checks that validate
these flags, and makes it easier to introduce new flags in the future.

No functional change intended.

Signed-off-by: Aaron Lewis <aaronlewis@google.com>
---
 arch/x86/include/uapi/asm/kvm.h | 2 ++
 arch/x86/kvm/x86.c              | 2 +-
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/x86/include/uapi/asm/kvm.h b/arch/x86/include/uapi/asm/kvm.h
index 63691a4c62d0..a9fecd3eab61 100644
--- a/arch/x86/include/uapi/asm/kvm.h
+++ b/arch/x86/include/uapi/asm/kvm.h
@@ -214,6 +214,8 @@ struct kvm_msr_list {
 struct kvm_msr_filter_range {
 #define KVM_MSR_FILTER_READ  (1 << 0)
 #define KVM_MSR_FILTER_WRITE (1 << 1)
+#define KVM_MSR_FILTER_RANGE_VALID_MASK (KVM_MSR_FILTER_READ | \
+					 KVM_MSR_FILTER_WRITE)
 	__u32 flags;
 	__u32 nmsrs; /* number of msrs in bitmap */
 	__u32 base;  /* MSR index the bitmap starts at */
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index adaec8d07a25..6c1a531e3b88 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -6349,7 +6349,7 @@ static int kvm_add_msr_filter(struct kvm_x86_msr_filter *msr_filter,
 	if (!user_range->nmsrs)
 		return 0;
 
-	if (user_range->flags & ~(KVM_MSR_FILTER_READ | KVM_MSR_FILTER_WRITE))
+	if (user_range->flags & ~KVM_MSR_FILTER_RANGE_VALID_MASK)
 		return -EINVAL;
 
 	if (!user_range->flags)
-- 
2.37.1.359.gd136c6c3e2-goog