[PATCH 4.18 41/79] x86/KVM/VMX: Add find_msr() helper function

[Greg Kroah-Hartman]

4.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Konrad Rzeszutek Wilk <konrad.w...@oracle.com>

.. to help find the MSR on either the guest or host MSR list.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.w...@oracle.com>
Signed-off-by: Thomas Gleixner <t...@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
 arch/x86/kvm/vmx.c |   31 ++++++++++++++++++-------------
 1 file changed, 18 insertions(+), 13 deletions(-)

--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -2432,9 +2432,20 @@ static void clear_atomic_switch_msr_spec
        vm_exit_controls_clearbit(vmx, exit);
 }
 
+static int find_msr(struct vmx_msrs *m, unsigned int msr)
+{
+       unsigned int i;
+
+       for (i = 0; i < m->nr; ++i) {
+               if (m->val[i].index == msr)
+                       return i;
+       }
+       return -ENOENT;
+}
+
 static void clear_atomic_switch_msr(struct vcpu_vmx *vmx, unsigned msr)
 {
-       unsigned i;
+       int i;
        struct msr_autoload *m = &vmx->msr_autoload;
 
        switch (msr) {
@@ -2455,11 +2466,8 @@ static void clear_atomic_switch_msr(stru
                }
                break;
        }
-       for (i = 0; i < m->guest.nr; ++i)
-               if (m->guest.val[i].index == msr)
-                       break;
-
-       if (i == m->guest.nr)
+       i = find_msr(&m->guest, msr);
+       if (i < 0)
                return;
        --m->guest.nr;
        --m->host.nr;
@@ -2483,7 +2491,7 @@ static void add_atomic_switch_msr_specia
 static void add_atomic_switch_msr(struct vcpu_vmx *vmx, unsigned msr,
                                  u64 guest_val, u64 host_val)
 {
-       unsigned i;
+       int i;
        struct msr_autoload *m = &vmx->msr_autoload;
 
        switch (msr) {
@@ -2518,16 +2526,13 @@ static void add_atomic_switch_msr(struct
                wrmsrl(MSR_IA32_PEBS_ENABLE, 0);
        }
 
-       for (i = 0; i < m->guest.nr; ++i)
-               if (m->guest.val[i].index == msr)
-                       break;
-
+       i = find_msr(&m->guest, msr);
        if (i == NR_AUTOLOAD_MSRS) {
                printk_once(KERN_WARNING "Not enough msr switch entries. "
                                "Can't add msr %x\n", msr);
                return;
-       } else if (i == m->guest.nr) {
-               ++m->guest.nr;
+       } else if (i < 0) {
+               i = m->guest.nr++;
                ++m->host.nr;
                vmcs_write32(VM_ENTRY_MSR_LOAD_COUNT, m->guest.nr);
                vmcs_write32(VM_EXIT_MSR_LOAD_COUNT, m->host.nr);