From: Sean Christopherson <seanjc@google.com>
To: Wanpeng Li <kernellwp@gmail.com>
Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
Paolo Bonzini <pbonzini@redhat.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
Aili Yao <yaoaili@kingsoft.com>
Subject: Re: [PATCH v2] KVM: LAPIC: Enable timer posted-interrupt when mwait/hlt is advertised
Date: Wed, 12 Jan 2022 00:39:15 +0000 [thread overview]
Message-ID: <Yd4jMyi4JIE+uh5o@google.com> (raw)
In-Reply-To: <1641471612-34483-1-git-send-email-wanpengli@tencent.com>
On Thu, Jan 06, 2022, Wanpeng Li wrote:
> From: Wanpeng Li <wanpengli@tencent.com>
>
> As commit 0c5f81dad46 (KVM: LAPIC: Inject timer interrupt via posted interrupt)
> mentioned that the host admin should well tune the guest setup, so that vCPUs
> are placed on isolated pCPUs, and with several pCPUs surplus for *busy* housekeeping.
> It is better to disable mwait/hlt/pause vmexits to keep the vCPUs in non-root
> mode. However, we may isolate pCPUs for other purpose like DPDK or we can make
> some guests isolated and others not, we may lose vmx preemption timer/timer fastpath
> due to not well tuned setup, and the checking in kvm_can_post_timer_interrupt()
> is not enough. Let's guarantee mwait/hlt is advertised before enabling posted-interrupt
> interrupt. vmx preemption timer/timer fastpath can continue to work if both of them
> are not advertised.
>
> Reported-by: Aili Yao <yaoaili@kingsoft.com>
> Cc: Aili Yao <yaoaili@kingsoft.com>
> Cc: Sean Christopherson <seanjc@google.com>
> Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
> ---
Reviewed-by: Sean Christopherson <seanjc@google.com>
next prev parent reply other threads:[~2022-01-12 0:39 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-06 12:20 [PATCH v2] KVM: LAPIC: Enable timer posted-interrupt when mwait/hlt is advertised Wanpeng Li
2022-01-12 0:39 ` Sean Christopherson [this message]
2022-01-19 7:12 ` Wanpeng Li
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=Yd4jMyi4JIE+uh5o@google.com \
--to=seanjc@google.com \
--cc=jmattson@google.com \
--cc=joro@8bytes.org \
--cc=kernellwp@gmail.com \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=pbonzini@redhat.com \
--cc=vkuznets@redhat.com \
--cc=wanpengli@tencent.com \
--cc=yaoaili@kingsoft.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.