[PATCH v3 05/10] KVM: x86/xen: Consolidate checks on Xen vCPU ID for singleshot timer hypercalls

[Sean Christopherson <seanjc@google.com>]

Hoist the checks on the Xen vCPU ID when handling set_singleshot_timer and
stop_singleshot_timer hypercalls out of their individual case-statements,
so that both checks on the ID are in common code.  kvm_xen_hcall_vcpu_op()
is already doubly committed to handling only singleshot timer hypercalls,
and even if that were to change in the future, the function could simply
be renamed and turned into a helper specifically for timer hypercalls.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 arch/x86/kvm/xen.c | 14 +++++---------
 1 file changed, 5 insertions(+), 9 deletions(-)

diff --git a/arch/x86/kvm/xen.c b/arch/x86/kvm/xen.c
index 27c1aeeab8af..db10f12d10cf 100644
--- a/arch/x86/kvm/xen.c
+++ b/arch/x86/kvm/xen.c
@@ -1614,13 +1614,13 @@ static bool kvm_xen_hcall_vcpu_op(struct kvm_vcpu *vcpu, bool longmode, int cmd,
 	if (vcpu->arch.xen.vcpu_id == XEN_VCPU_ID_INVALID)
 		return false;
 
+	if (vcpu->arch.xen.vcpu_id != vcpu_id) {
+		*r = -EINVAL;
+		return true;
+	}
+
 	switch (cmd) {
 	case VCPUOP_set_singleshot_timer:
-		if (vcpu->arch.xen.vcpu_id != vcpu_id) {
-			*r = -EINVAL;
-			return true;
-		}
-
 		/*
 		 * The only difference for 32-bit compat is the 4 bytes of
 		 * padding after the interesting part of the structure. So
@@ -1648,10 +1648,6 @@ static bool kvm_xen_hcall_vcpu_op(struct kvm_vcpu *vcpu, bool longmode, int cmd,
 		return true;
 
 	case VCPUOP_stop_singleshot_timer:
-		if (vcpu->arch.xen.vcpu_id != vcpu_id) {
-			*r = -EINVAL;
-			return true;
-		}
 		kvm_xen_stop_timer(vcpu);
 		*r = 0;
 		return true;
-- 
2.55.0.rc0.799.gd6f94ed593-goog