Commit 7a504920 authored by Rusty Russell's avatar Rusty Russell
Browse files

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: default avatarRusty Russell <>
parent 27de22d0
......@@ -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;
case 1: /* Basic feature request. */
/* We only allow kernel to see SSE3, CMPXCHG16B and SSSE3 */
*cx &= 0x00002201;
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