qemu-devel.nongnu.org archive mirror
 help / color / mirror / Atom feed
From: Jan Kiszka <jan.kiszka@siemens.com>
To: Liran Alon <liran.alon@oracle.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>, qemu-devel <qemu-devel@nongnu.org>
Subject: Re: [Qemu-devel] [PATCH] i386/kvm: Do not sync nested state during runtime
Date: Mon, 22 Jul 2019 12:20:31 +0200	[thread overview]
Message-ID: <0972ccd9-386d-b618-f055-e8ae0181b64e@siemens.com> (raw)
In-Reply-To: <A9036EC6-848A-4D42-95AF-42E2302EEC0B@oracle.com>

On 22.07.19 11:44, Liran Alon wrote:
> 
> 
>> On 22 Jul 2019, at 7:00, Jan Kiszka <jan.kiszka@siemens.com> wrote:
>>
>> Writing the nested state e.g. after a vmport access can invalidate
>> important parts of the kernel-internal state, and it is not needed as
>> well. So leave this out from KVM_PUT_RUNTIME_STATE.
>>
>> Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
>> Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
> 
> As QEMU never modifies vCPU nested-state in userspace besides in vmload and vCPU creation,
> shouldn’t this be under KVM_PUT_FULL_STATE? Same as the call to kvm_arch_set_tsc_khz().

Reset is a relevant modification as well. If we do not write back a state that
is disabling virtualization, we break.

Jan

-- 
Siemens AG, Corporate Technology, CT RDA IOT SES-DE
Corporate Competence Center Embedded Linux


  reply	other threads:[~2019-07-22 10:20 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-07-22  4:00 [Qemu-devel] [PATCH] i386/kvm: Do not sync nested state during runtime Jan Kiszka
2019-07-22  9:44 ` Liran Alon
2019-07-22 10:20   ` Jan Kiszka [this message]
2019-07-22 10:31     ` Liran Alon
2019-07-22 10:43       ` Jan Kiszka
2019-07-22 11:23         ` Paolo Bonzini

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=0972ccd9-386d-b618-f055-e8ae0181b64e@siemens.com \
    --to=jan.kiszka@siemens.com \
    --cc=liran.alon@oracle.com \
    --cc=pbonzini@redhat.com \
    --cc=qemu-devel@nongnu.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).