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authorRusty Russell <rusty@rustcorp.com.au>2009-07-18 05:47:44 +0200
committerRusty Russell <rusty@rustcorp.com.au>2009-07-17 14:17:45 +0200
commit7a5049205f7265620c48781814155f2763e70abb (patch)
tree7b3cf5ec83687e74028bbfa100dac4e6d449155a /arch/x86/lguest
parentlguest: remove unnecessary forward struct declaration (diff)
downloadlinux-7a5049205f7265620c48781814155f2763e70abb.tar.xz
linux-7a5049205f7265620c48781814155f2763e70abb.zip
lguest: restrict CPUID to avoid perf counter wrmsr
Avoid the following: [ 0.012093] WARNING: at arch/x86/kernel/apic/apic.c:249 native_apic_write_dummy+0x2f/0x40() Rather than chase each new cpuid-detected feature, just lie about the highest valid CPUID so this code is never run. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Diffstat (limited to 'arch/x86/lguest')
-rw-r--r--arch/x86/lguest/boot.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/arch/x86/lguest/boot.c b/arch/x86/lguest/boot.c
index 0188fd37b6c0..f2bf1f73d468 100644
--- a/arch/x86/lguest/boot.c
+++ b/arch/x86/lguest/boot.c
@@ -379,6 +379,11 @@ static void lguest_cpuid(unsigned int *ax, unsigned int *bx,
native_cpuid(ax, bx, cx, dx);
switch (function) {
+ case 0: /* ID and highest CPUID. Futureproof a little by sticking to
+ * older ones. */
+ if (*ax > 5)
+ *ax = 5;
+ break;
case 1: /* Basic feature request. */
/* We only allow kernel to see SSE3, CMPXCHG16B and SSSE3 */
*cx &= 0x00002201;