Re: [BUG + PATCH/Bugfix] x86/lguest: fix pgdir pmd index calculation

Ingo Molnar
2008-02-29T19:59:26Z

* Ahmed S. Darwish <darwish.07@gmail.com> wrote:

> On the lguest _guest_ side, 'cpu_has_tsc' is _always_ false (due to
> lguest using his own clocksource ?), thus a guest with a pentium+ cpu
> always panics with:

does the "RDTSC" instruction work in an lguest guest? If not, then the
lguest kernel is correct in not exposing it - and then the solution is
to build a non-TSC guest kernel. Does the patch below help?

but if the RDTSC instruction does work in an lguest guest, then the
proper approach would be to expose it in the CPU features.

Ingo
---
arch/x86/Kconfig.cpu | 1 +
1 file changed, 1 insertion(+)

Index: linux-x86.q/arch/x86/Kconfig.cpu
===================================================================
--- linux-x86.q.orig/arch/x86/Kconfig.cpu
+++ linux-x86.q/arch/x86/Kconfig.cpu
@@ -393,6 +393,7 @@ config X86_P6_NOP
config X86_TSC
def_bool y
depends on ((MWINCHIP3D || MWINCHIP2 || MCRUSOE || MEFFICEON || MCYRIXIII || MK7 || MK6 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || M586MMX || M586TSC || MK8 || MVIAC3_2 || MVIAC7 || MGEODEGX1 || MGEODE_LX || MCORE2) && !X86_NUMAQ) || X86_64
+ depends on !LGUEST_GUEST

# this should be set for all -march=.. options where the compiler
# generates cmov.