From: Vitaly Kuznetsov <vkuznets@redhat.com>
To: Dexuan Cui <decui@microsoft.com>
Cc: bp@alien8.de, haiyangz@microsoft.com, hpa@zytor.com,
kys@microsoft.com, linux-hyperv@vger.kernel.org,
linux-kernel@vger.kernel.org, mingo@redhat.com,
sthemmin@microsoft.com, tglx@linutronix.de, x86@kernel.org,
mikelley@microsoft.com, wei.liu@kernel.org, kvm@vger.kernel.org
Subject: Re: [PATCH] x86/hyperv: Suspend/resume the VP assist page for hibernation
Date: Fri, 17 Apr 2020 12:03:18 +0200 [thread overview]
Message-ID: <87blnqv389.fsf@vitty.brq.redhat.com> (raw)
In-Reply-To: <1587104999-28927-1-git-send-email-decui@microsoft.com>
Dexuan Cui <decui@microsoft.com> writes:
> Unlike the other CPUs, CPU0 is never offlined during hibernation. So in the
> resume path, the "new" kernel's VP assist page is not suspended (i.e.
> disabled), and later when we jump to the "old" kernel, the page is not
> properly re-enabled for CPU0 with the allocated page from the old kernel.
>
> So far, the VP assist page is only used by hv_apic_eoi_write().
No, not only for that ('git grep hv_get_vp_assist_page')
KVM on Hyper-V also needs VP assist page to use Enlightened VMCS. In
particular, Enlightened VMPTR is written there.
This makes me wonder: how does hibernation work with KVM in case we use
Enlightened VMCS and we have VMs running? We need to make sure VP Assist
page content is preserved.
--
Vitaly
next prev parent reply other threads:[~2020-04-17 10:03 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-17 6:29 [PATCH] x86/hyperv: Suspend/resume the VP assist page for hibernation Dexuan Cui
2020-04-17 9:07 ` Wei Liu
2020-04-17 22:44 ` Dexuan Cui
2020-04-17 10:03 ` Vitaly Kuznetsov [this message]
2020-04-17 10:55 ` Wei Liu
2020-04-17 12:03 ` Vitaly Kuznetsov
2020-04-17 13:08 ` Wei Liu
2020-04-17 23:07 ` Dexuan Cui
2020-04-17 11:00 ` Wei Liu
2020-04-17 23:47 ` Dexuan Cui
2020-04-20 12:08 ` Wei Liu
2020-04-20 16:40 ` Dexuan Cui
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=87blnqv389.fsf@vitty.brq.redhat.com \
--to=vkuznets@redhat.com \
--cc=bp@alien8.de \
--cc=decui@microsoft.com \
--cc=haiyangz@microsoft.com \
--cc=hpa@zytor.com \
--cc=kvm@vger.kernel.org \
--cc=kys@microsoft.com \
--cc=linux-hyperv@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mikelley@microsoft.com \
--cc=mingo@redhat.com \
--cc=sthemmin@microsoft.com \
--cc=tglx@linutronix.de \
--cc=wei.liu@kernel.org \
--cc=x86@kernel.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).