From: Paolo Bonzini <pbonzini@redhat.com>
To: Igor Mammedov <imammedo@redhat.com>, linux-kernel@vger.kernel.org
Cc: x86@kernel.org, hpa@zytor.com, mingo@redhat.com,
tglx@linutronix.de, kvm@vger.kernel.org, mtosatti@redhat.com
Subject: Re: [PATCH 2/2] x86: kvm: do not advertise stable clocksource if CPU has TSC drift BUG
Date: Thu, 31 Jul 2014 16:38:49 +0200 [thread overview]
Message-ID: <53DA54F9.8090605@redhat.com> (raw)
In-Reply-To: <1406800033-13404-3-git-send-email-imammedo@redhat.com>
Il 31/07/2014 11:47, Igor Mammedov ha scritto:
> Signed-off-by: Igor Mammedov <imammedo@redhat.com>
> ---
> arch/x86/kvm/cpuid.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
> index 38a0afe..f519823 100644
> --- a/arch/x86/kvm/cpuid.c
> +++ b/arch/x86/kvm/cpuid.c
> @@ -478,8 +478,9 @@ static inline int __do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
> (1 << KVM_FEATURE_CLOCKSOURCE2) |
> (1 << KVM_FEATURE_ASYNC_PF) |
> (1 << KVM_FEATURE_PV_EOI) |
> - (1 << KVM_FEATURE_CLOCKSOURCE_STABLE_BIT) |
> (1 << KVM_FEATURE_PV_UNHALT);
> + if (!static_cpu_has_bug(X86_BUG_AMD_TSC_DRIFT))
> + entry->eax |= (1 << KVM_FEATURE_CLOCKSOURCE_STABLE_BIT);
>
> if (sched_info_on())
> entry->eax |= (1 << KVM_FEATURE_STEAL_TIME);
>
Marcelo, is there anything we can do if the VM migrates from a sane host
to a buggy one?
Paolo
prev parent reply other threads:[~2014-07-31 14:38 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-07-31 9:47 [PATCH 0/2] Avoid using TSC clocksource on AMD APUs affected by erratum 778 Igor Mammedov
2014-07-31 9:47 ` [PATCH 1/2] x86: AMD: mark TSC unstable on APU family 15h models 10h-1fh Igor Mammedov
2014-07-31 15:47 ` Borislav Petkov
2014-07-31 16:33 ` Paolo Bonzini
2014-08-01 9:02 ` Borislav Petkov
2014-07-31 9:47 ` [PATCH 2/2] x86: kvm: do not advertise stable clocksource if CPU has TSC drift BUG Igor Mammedov
2014-07-31 14:38 ` Paolo Bonzini [this message]
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