Re: [PATCH 1/4] Fix tboot enabled macro

[Jan Kiszka <jan.kiszka@web.de>]

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Zachary Amsden wrote:
> 
(please post inlined - I have to copy your patch manually now)

> From 614d5fa8bba5f98fd3cb1d66d63b0b70ca98fe51 Mon Sep 17 00:00:00 2001
> From: Zachary Amsden <zamsden@redhat.com>
> Date: Fri, 14 May 2010 12:25:14 -1000
> Subject: [PATCH 1/5] Fix tboot_enabled macro; was present in 2.6.33
> 
> Signed-off-by: Zachary Amsden <zamsden@redhat.com>
> ---
>  x86/external-module-compat.h |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/x86/external-module-compat.h b/x86/external-module-compat.h
> index 7d793a0..09bf232 100644
> --- a/x86/external-module-compat.h
> +++ b/x86/external-module-compat.h
> @@ -770,7 +770,7 @@ static inline void hw_breakpoint_restore(void)
>  #define percpu_write(t, v)	__get_cpu_var(t) = v
>  #endif
>  
> -#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,35)
> +#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,33)
>  #define tboot_enabled()		0
>  #endif

This is for CONFIG_INTEL_TXT enabled? Good point but needs to be solved
differently. tboot, the variable that is checked by the original header,
is not exported to modules. I wonder how this worked out for you...

Solution should be: hack tboot_enabled to kvm_tboot_enabled and
unconditionally define that to 0 for older kernels. If tboot is actually
enabled in hardware, KVM may not load but I'm unsure if it's OK to
assume tboot == 1 for that case or if that will cause breakages if it's
off instead - CC'ing the KVM patch author.

Jan


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