[Xen-changelog] [xen-unstable] x86/vMCE: don't advertise features we don't support

[Xen patchbot-unstable <patchbot@xxxxxxx>]

# HG changeset patch
# User Jan Beulich <jbeulich@xxxxxxxx>
# Date 1330070623 -3600
# Node ID e80b0bb4470b944a5b52a91c0ec85a1d65d18c55
# Parent  0c3d19f40ab145d101de84051c3e00eef17fa1cb
x86/vMCE: don't advertise features we don't support

... or even know of. Apart from CMCI, which was masked off already,
this now also suppresses the advertising of extended state registers
(reading of which would likely be meaningless in a guest and represent
an information leak).

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
Acked-by: Keir Fraser <keir@xxxxxxx>
---


diff -r 0c3d19f40ab1 -r e80b0bb4470b xen/arch/x86/cpu/mcheck/vmce.c
--- a/xen/arch/x86/cpu/mcheck/vmce.c    Mon Feb 20 22:16:32 2012 +0100
+++ b/xen/arch/x86/cpu/mcheck/vmce.c    Fri Feb 24 09:03:43 2012 +0100
@@ -457,7 +457,7 @@
 
     rdmsrl(MSR_IA32_MCG_CAP, value);
     /* For Guest vMCE usage */
-    g_mcg_cap = value & ~MCG_CMCI_P;
+    g_mcg_cap = value & (MCG_CAP_COUNT | MCG_CTL_P | MCG_TES_P | MCG_SER_P);
     if (value & MCG_CTL_P)
         rdmsrl(MSR_IA32_MCG_CTL, h_mcg_ctl);
 
diff -r 0c3d19f40ab1 -r e80b0bb4470b xen/arch/x86/cpu/mcheck/x86_mca.h
--- a/xen/arch/x86/cpu/mcheck/x86_mca.h Mon Feb 20 22:16:32 2012 +0100
+++ b/xen/arch/x86/cpu/mcheck/x86_mca.h Fri Feb 24 09:03:43 2012 +0100
@@ -30,12 +30,13 @@
 
 
 /* Bitfield of the MSR_IA32_MCG_CAP register */
-#define MCG_SER_P               (1UL<<24)
 #define MCG_CAP_COUNT           0x00000000000000ffULL
-#define MCG_CTL_P               0x0000000000000100ULL
-#define MCG_EXT_P              (1UL<<9)
-#define MCG_EXT_CNT            (16)
-#define MCG_CMCI_P             (1UL<<10)
+#define MCG_CTL_P               (1ULL<<8)
+#define MCG_EXT_P               (1ULL<<9)
+#define MCG_CMCI_P              (1ULL<<10)
+#define MCG_TES_P               (1ULL<<11)
+#define MCG_EXT_CNT             16
+#define MCG_SER_P               (1ULL<<24)
 /* Other bits are reserved */
 
 /* Bitfield of the MSR_IA32_MCG_STATUS register */

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