KVM: x86: Add a VALID_MASK for the MSR exit reason flags

Add the mask KVM_MSR_EXIT_REASON_VALID_MASK for the MSR exit reason
flags.  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>
Message-Id: <20220921151525.904162-3-aaronlewis@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index cbec2e675c18f90e935ad642441641f0db8814bb..9ba8c1b73db49b1c27a9df0d1ff936a3f116309d 100644 (file)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -6230,9 +6230,7 @@ split_irqchip_unlock:
                break;
        case KVM_CAP_X86_USER_SPACE_MSR:
                r = -EINVAL;
-               if (cap->args[0] & ~(KVM_MSR_EXIT_REASON_INVAL |
-                                    KVM_MSR_EXIT_REASON_UNKNOWN |
-                                    KVM_MSR_EXIT_REASON_FILTER))
+               if (cap->args[0] & ~KVM_MSR_EXIT_REASON_VALID_MASK)
                        break;
                kvm->arch.user_space_msr_mask = cap->args[0];
                r = 0;

diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 0d5d4419139aeca5a932fa9f0ac4e29330f75767..7fea12369245a24cd14560a975804157b740fd64 100644 (file)
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -485,6 +485,9 @@ struct kvm_run {
 #define KVM_MSR_EXIT_REASON_INVAL      (1 << 0)
 #define KVM_MSR_EXIT_REASON_UNKNOWN    (1 << 1)
 #define KVM_MSR_EXIT_REASON_FILTER     (1 << 2)
+#define KVM_MSR_EXIT_REASON_VALID_MASK (KVM_MSR_EXIT_REASON_INVAL   |  \
+                                        KVM_MSR_EXIT_REASON_UNKNOWN |  \
+                                        KVM_MSR_EXIT_REASON_FILTER)
                        __u32 reason; /* kernel -> user */
                        __u32 index; /* kernel -> user */
                        __u64 data; /* kernel <-> user */