[Xen-changelog] [xen-4.1-testing] x86/xenoprof: fix kernel/user mode detection for HVM

[Xen patchbot-4.1-testing <patchbot@xxxxxxx>]

# HG changeset patch
# User Jacob Shin <jacob.shin@xxxxxxx>
# Date 1351497674 -3600
# Node ID de551622e12493ca8747a69d68cd08103411a220
# Parent  9cedd98b1835418d0a01e116c96fe6b3fb1660cb
x86/xenoprof: fix kernel/user mode detection for HVM

While trying oprofile under Xen, I noticed that HVM passive domain's
kernel addresses were showing up as user application. It turns out
under HVM get_cpu_user_regs()->cs contains 0x0000beef.

Signed-off-by: Jacob Shin <jacob.shin@xxxxxxx>

Don't cast away const-ness. Use SS instead of CS to determine ring.
Special-case real and protected mode.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
Acked-by: Keir Fraser <keir@xxxxxxx>
xen-unstable changeset: 26055:14e32621dbaf
xen-unstable date: Mon Oct 15 13:04:51 UTC 2012
---


diff -r 9cedd98b1835 -r de551622e124 xen/arch/x86/oprofile/xenoprof.c
--- a/xen/arch/x86/oprofile/xenoprof.c  Mon Oct 29 08:59:47 2012 +0100
+++ b/xen/arch/x86/oprofile/xenoprof.c  Mon Oct 29 09:01:14 2012 +0100
@@ -82,10 +82,21 @@ int xenoprofile_get_mode(struct vcpu *v,
     if ( !guest_mode(regs) )
         return 2;
 
-    if ( is_hvm_vcpu(v) )
-        return ((regs->cs & 3) != 3);
+    if ( !is_hvm_vcpu(v) )
+        return guest_kernel_mode(v, regs);
 
-    return guest_kernel_mode(v, regs);  
+    switch ( hvm_guest_x86_mode(v) )
+    {
+        struct segment_register ss;
+
+    case 0: /* real mode */
+        return 1;
+    case 1: /* vm86 mode */
+        return 0;
+    default:
+        hvm_get_segment_register(v, x86_seg_ss, &ss);
+        return (ss.sel & 3) != 3;
+    }
 }
 
 /*

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