From: Sean Christopherson <seanjc@google.com>
To: David Sauerwein <dssauerw@amazon.de>
Cc: "Paolo Bonzini" <pbonzini@redhat.com>,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
"David Woodhouse" <dwmw@amazon.co.uk>,
nh-open-source@amazon.com,
"Jan H. Schönherr" <jschoenh@amazon.de>
Subject: Re: [PATCH] x86: kvm: Initialize static calls before SMP boot
Date: Wed, 4 Mar 2026 11:19:12 -0800 [thread overview]
Message-ID: <aaiFsN3Jn_C5bTnd@google.com> (raw)
In-Reply-To: <20260304165012.13660-1-dssauerw@amazon.de>
On Wed, Mar 04, 2026, David Sauerwein wrote:
> Updating static calls is expensive on wide SMP systems because all
> online CPUs need to act in a coordinated manner for code patching to
> work as expected.
Eww. I am very, very against an early_initcall() in KVM, even if we pinky swear
we'll never use it for anything except prefetching static_call() targets. The
initcall framework lacks the ability to express dependencies, and KVM most definitely
has dependencies on arch and subsys code.
I also don't like hacking KVM to workaround what is effectively a generic
infrastructure issue/limitation.
Have y'all looked at Valentin's series to defer IPIs? I assume/hope deferring
IPIs would reduce the delay observed when doing the patching.
https://lore.kernel.org/all/20251010153839.151763-1-vschneid@redhat.com
next prev parent reply other threads:[~2026-03-04 19:19 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-04 16:50 [PATCH] x86: kvm: Initialize static calls before SMP boot David Sauerwein
2026-03-04 19:19 ` Sean Christopherson [this message]
2026-03-06 11:19 ` 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=aaiFsN3Jn_C5bTnd@google.com \
--to=seanjc@google.com \
--cc=dssauerw@amazon.de \
--cc=dwmw@amazon.co.uk \
--cc=jschoenh@amazon.de \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=nh-open-source@amazon.com \
--cc=pbonzini@redhat.com \
/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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.