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>

parent 27de22d0

arch/x86/lguest/boot.c

+5 −0

Original line number	Diff line number	Diff line
		@@ -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;