From: Paolo Bonzini <pbonzini@redhat.com>
To: Vitaly Kuznetsov <vkuznets@redhat.com>, qemu-devel@nongnu.org
Cc: Marcelo Tosatti <mtosatti@redhat.com>,
Richard Henderson <richard.henderson@linaro.org>,
Eduardo Habkost <ehabkost@redhat.com>,
"Dr . David Alan Gilbert" <dgilbert@redhat.com>
Subject: Re: [PATCH 3/3] i386: Make sure kvm_arch_set_tsc_khz() succeeds on migration when 'hv-reenlightenment' was exposed
Date: Fri, 19 Mar 2021 12:04:13 +0100 [thread overview]
Message-ID: <7acdfa23-da34-c76e-1a44-cf611fe94917@redhat.com> (raw)
In-Reply-To: <87mtuz5vkp.fsf@vitty.brq.redhat.com>
On 19/03/21 10:41, Vitaly Kuznetsov wrote:
>> What I want to achieve is to forbid migration of VMs with
>> reenlightenment, if they don't also specify tsc-khz to the frequency of
>> the TSC on the source host. We can't check it at the beginning of
>> migration, but at least we can check it at the end.
>>
>> Maybe we're talking about two different things?
> No, your suggestion basically extends mine and I'm just trying to
> understand the benefit. With my suggestion, it is not required to
> specify tsc-khz on the source, we just take 'native' tsc frequency as a
> reference. Post-migration, we require that KVM_SET_TSC_KHZ succeeds (and
> not just 'try' like kvm_arch_put_registers() does so we effectively
> break migration when we are unable to set the desired TSC frequency
> (also at the end).
Oh, okay, I understand the confusion; I was thinking of checking for
user_tsc_khz in the post-load function for reenlightenment, not in the
command line processing.
Paolo
next prev parent reply other threads:[~2021-03-19 11:05 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-18 16:02 [PATCH 0/3] i386: Make sure TSC frequency is preserved across migration when Hyper-V reenlightenment is in use Vitaly Kuznetsov
2021-03-18 16:02 ` [PATCH 1/3] i386: Make Hyper-V related sections KVM only Vitaly Kuznetsov
2021-03-18 16:06 ` Paolo Bonzini
2021-03-18 16:02 ` [PATCH 2/3] i386: Fix 'hypercall_hypercall' typo Vitaly Kuznetsov
2021-03-18 16:12 ` Paolo Bonzini
2021-03-18 16:02 ` [PATCH 3/3] i386: Make sure kvm_arch_set_tsc_khz() succeeds on migration when 'hv-reenlightenment' was exposed Vitaly Kuznetsov
2021-03-18 16:12 ` Paolo Bonzini
2021-03-18 16:38 ` Vitaly Kuznetsov
2021-03-18 17:36 ` Paolo Bonzini
2021-03-19 9:41 ` Vitaly Kuznetsov
2021-03-19 11:04 ` Paolo Bonzini [this message]
2021-03-19 12:02 ` Vitaly Kuznetsov
2021-03-18 18:03 ` Marcelo Tosatti
2021-03-19 9:46 ` Vitaly Kuznetsov
2021-03-18 20:13 ` Dr. David Alan Gilbert
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