[PATCH 4.20 63/92] kvm: vmx: Fix entry number check for add_atomic_switch_msr()

[Greg Kroah-Hartman]

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

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

From: Xiaoyao Li <xiaoyao...@linux.intel.com>

commit 98ae70cc476e833332a2c6bb72f941a25f0de226 upstream.

Commit ca83b4a7f2d068da79a0 ("x86/KVM/VMX: Add find_msr() helper function")
introduces the helper function find_msr(), which returns -ENOENT when
not find the msr in vmx->msr_autoload.guest/host. Correct checking contion
of no more available entry in vmx->msr_autoload.

Fixes: ca83b4a7f2d0 ("x86/KVM/VMX: Add find_msr() helper function")
Cc: sta...@vger.kernel.org
Signed-off-by: Xiaoyao Li <xiaoyao...@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonz...@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>

---
 arch/x86/kvm/vmx.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -2779,7 +2779,8 @@ static void add_atomic_switch_msr(struct
        if (!entry_only)
                j = find_msr(&m->host, msr);
 
-       if (i == NR_AUTOLOAD_MSRS || j == NR_AUTOLOAD_MSRS) {
+       if ((i < 0 && m->guest.nr == NR_AUTOLOAD_MSRS) ||
+               (j < 0 &&  m->host.nr == NR_AUTOLOAD_MSRS)) {
                printk_once(KERN_WARNING "Not enough msr switch entries. "
                                "Can't add msr %x\n", msr);
                return;