From: David Edmondson <dme@dme.org>
To: Richard Henderson <richard.henderson@linaro.org>, qemu-devel@nongnu.org
Cc: Eduardo Habkost <ehabkost@redhat.com>,
kvm@vger.kernel.org, Michael Roth <michael.roth@amd.com>,
Marcelo Tosatti <mtosatti@redhat.com>,
Cameron Esfahani <dirty@apple.com>,
babu.moger@amd.com, Roman Bolshakov <r.bolshakov@yadro.com>,
Paolo Bonzini <pbonzini@redhat.com>
Subject: Re: [RFC PATCH 8/8] target/i386: Move X86XSaveArea into TCG
Date: Thu, 08 Jul 2021 17:13:57 +0100 [thread overview]
Message-ID: <m235so4wca.fsf@dme.org> (raw)
In-Reply-To: <e4a048f5-cc6d-7bbe-6659-54075cafb9c6@linaro.org>
On Thursday, 2021-07-08 at 08:22:02 -07, Richard Henderson wrote:
> On 7/8/21 12:45 AM, David Edmondson wrote:
>> Actually, that's nonsense. With KVM or HVF we have to use the offsets of
>> the host CPU, as the hardware won't do anything else, irrespective of
>> the general CPU model chosen.
>>
>> To have KVM -> TCG migration work it would be necessary to pass the
>> offsets in the migration stream and have TCG observe them, as you
>> originally said.
>>
>> TCG -> KVM migration would only be possible if TCG was configured to use
>> the same offsets as would later required by KVM (meaning, the host CPU).
>
> And kvm -> kvm migration, with the same general cpu model chosen, but with different host
> cpus with different offsets?
>
> It seems like we must migrate then and verify the offsets in that case, so that we can
> fail the migration.
Agreed.
I will look into migrating the offsets.
dme.
--
The sound of a barking dog on a loop, a plane rises in the crystal blue.
next prev parent reply other threads:[~2021-07-08 17:07 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-05 10:46 [RFC PATCH 0/8] Derive XSAVE state component offsets from CPUID leaf 0xd where possible David Edmondson
2021-07-05 10:46 ` [RFC PATCH 1/8] target/i386: Declare constants for XSAVE offsets David Edmondson
2021-07-05 10:46 ` [RFC PATCH 2/8] target/i386: Consolidate the X86XSaveArea offset checks David Edmondson
2021-07-05 10:46 ` [RFC PATCH 3/8] target/i386: Clarify the padding requirements of X86XSaveArea David Edmondson
2021-07-05 10:46 ` [RFC PATCH 4/8] target/i386: Pass buffer and length to XSAVE helper David Edmondson
2021-07-05 10:46 ` [RFC PATCH 5/8] target/i386: Make x86_ext_save_areas visible outside cpu.c David Edmondson
2021-07-05 10:46 ` [RFC PATCH 6/8] target/i386: Observe XSAVE state area offsets David Edmondson
2021-07-05 10:46 ` [RFC PATCH 7/8] target/i386: Populate x86_ext_save_areas offsets using cpuid where possible David Edmondson
2021-07-05 10:46 ` [RFC PATCH 8/8] target/i386: Move X86XSaveArea into TCG David Edmondson
2021-07-07 1:09 ` Richard Henderson
2021-07-07 6:51 ` Paolo Bonzini
2021-07-07 10:10 ` David Edmondson
2021-07-08 7:45 ` David Edmondson
2021-07-08 15:22 ` Richard Henderson
2021-07-08 16:13 ` David Edmondson [this message]
2021-07-05 16:57 ` [RFC PATCH 0/8] Derive XSAVE state component offsets from CPUID leaf 0xd where possible Paolo Bonzini
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