KVM: VMX: Add vmx_setup_uret_msr() to handle lookup and swap

Add vmx_setup_uret_msr() to wrap the lookup and manipulation of the uret
MSRs array during setup_msrs().  In addition to consolidating code, this
eliminates move_msr_up(), which while being a very literally description
of the function, isn't exacly helpful in understanding the net effect of
the code.

No functional change intended.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20200923180409.32255-12-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 1ad9fac..3300e37 100644 (file)
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -1614,12 +1614,15 @@ static void vmx_queue_exception(struct kvm_vcpu *vcpu)
        vmx_clear_hlt(vcpu);
 }
 
-/*
- * Swap MSR entry in host/guest MSR entry array.
- */
-static void move_msr_up(struct vcpu_vmx *vmx, int from, int to)
+static void vmx_setup_uret_msr(struct vcpu_vmx *vmx, unsigned int msr)
 {
        struct vmx_uret_msr tmp;
+       int from, to;
+
+       from = __vmx_find_uret_msr(vmx, msr);
+       if (from < 0)
+               return;
+       to = vmx->nr_active_uret_msrs++;
 
        tmp = vmx->guest_uret_msrs[to];
        vmx->guest_uret_msrs[to] = vmx->guest_uret_msrs[from];
@@ -1633,42 +1636,26 @@ static void move_msr_up(struct vcpu_vmx *vmx, int from, int to)
  */
 static void setup_msrs(struct vcpu_vmx *vmx)
 {
-       int nr_active_uret_msrs, index;
-
-       nr_active_uret_msrs = 0;
+       vmx->guest_uret_msrs_loaded = false;
+       vmx->nr_active_uret_msrs = 0;
 #ifdef CONFIG_X86_64
        /*
         * The SYSCALL MSRs are only needed on long mode guests, and only
         * when EFER.SCE is set.
         */
        if (is_long_mode(&vmx->vcpu) && (vmx->vcpu.arch.efer & EFER_SCE)) {
-               index = __vmx_find_uret_msr(vmx, MSR_STAR);
-               if (index >= 0)
-                       move_msr_up(vmx, index, nr_active_uret_msrs++);
-               index = __vmx_find_uret_msr(vmx, MSR_LSTAR);
-               if (index >= 0)
-                       move_msr_up(vmx, index, nr_active_uret_msrs++);
-               index = __vmx_find_uret_msr(vmx, MSR_SYSCALL_MASK);
-               if (index >= 0)
-                       move_msr_up(vmx, index, nr_active_uret_msrs++);
+               vmx_setup_uret_msr(vmx, MSR_STAR);
+               vmx_setup_uret_msr(vmx, MSR_LSTAR);
+               vmx_setup_uret_msr(vmx, MSR_SYSCALL_MASK);
        }
 #endif
-       if (update_transition_efer(vmx)) {
-               index = __vmx_find_uret_msr(vmx, MSR_EFER);
-               if (index >= 0)
-                       move_msr_up(vmx, index, nr_active_uret_msrs++);
-       }
-       if (guest_cpuid_has(&vmx->vcpu, X86_FEATURE_RDTSCP)) {
-               index = __vmx_find_uret_msr(vmx, MSR_TSC_AUX);
-               if (index >= 0)
-                       move_msr_up(vmx, index, nr_active_uret_msrs++);
-       }
-       index = __vmx_find_uret_msr(vmx, MSR_IA32_TSX_CTRL);
-       if (index >= 0)
-               move_msr_up(vmx, index, nr_active_uret_msrs++);
+       if (update_transition_efer(vmx))
+               vmx_setup_uret_msr(vmx, MSR_EFER);
 
-       vmx->nr_active_uret_msrs = nr_active_uret_msrs;
-       vmx->guest_uret_msrs_loaded = false;
+       if (guest_cpuid_has(&vmx->vcpu, X86_FEATURE_RDTSCP))
+               vmx_setup_uret_msr(vmx, MSR_TSC_AUX);
+
+       vmx_setup_uret_msr(vmx, MSR_IA32_TSX_CTRL);
 
        if (cpu_has_vmx_msr_bitmap())
                vmx_update_msr_bitmap(&vmx->vcpu);