Re: [PATCH] KVM: x86: fix bogus warning about reserved bits

From: Borislav Petkov
Date: Thu Sep 24 2015 - 06:12:40 EST


On Thu, Sep 24, 2015 at 11:23:08AM +0800, Xiao Guangrong wrote:
> >+static inline bool
> >+boot_cpu_is_amd(void)
> >+{
> >+ WARN_ON_ONCE(!tdp_enabled);
> >+ return shadow_x_mask != 0;
>
> shadow_x_mask != 0 is Intel's CPU.
>
> Borislav, could you please check shadow_x_mask == 0 instead and test it again?

That did the trick:

[ 62.640392] kvm: zapping shadow pages for mmio generation wraparound
[ 63.100301] cpuid(0).ebx = 68747541
[ 63.193426] kvm [3748]: vcpu0 unhandled rdmsr: 0xc0010112
[ 64.538294] kvm [3748]: vcpu0 unhandled rdmsr: 0xc0011021
[ 64.866263] kvm [3748]: vcpu1 unhandled rdmsr: 0xc0011021
[ 64.971972] kvm [3748]: vcpu2 unhandled rdmsr: 0xc0011021
[ 65.070376] kvm [3748]: vcpu3 unhandled rdmsr: 0xc0011021
[ 65.170625] kvm [3748]: vcpu4 unhandled rdmsr: 0xc0011021
[ 65.272838] kvm [3748]: vcpu5 unhandled rdmsr: 0xc0011021
[ 65.374288] kvm [3748]: vcpu6 unhandled rdmsr: 0xc0011021
[ 65.474825] kvm [3748]: vcpu7 unhandled rdmsr: 0xc0011021

That's all I got in dmesg from booting the guest - no more mmio PF
warnings.

Thanks.

--
Regards/Gruss,
Boris.

ECO tip #101: Trim your mails when you reply.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/