From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E00B8C19F2D for ; Tue, 9 Aug 2022 09:22:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239196AbiHIJWl (ORCPT ); Tue, 9 Aug 2022 05:22:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51800 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239111AbiHIJW1 (ORCPT ); Tue, 9 Aug 2022 05:22:27 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 28EFBDF56; Tue, 9 Aug 2022 02:22:24 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=MIME-Version:Content-Type:References: In-Reply-To:Date:Cc:To:From:Subject:Message-ID:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=l6PutXL7aUBHBzO2nIvIBtJPp1k0u6SIve17NUt9Hag=; b=ltF9ULBtg2lhQsDlzGx5DXlgLr Xmh9fMIjvg02qpKXzRvcaTah09ulnbm1CVjs5BonCXMqjFLfjGUCSoXFp6h979C+1meuN3tT4Ew9l DnwwZMBCAE5A6MsPAQVRqUCgj2twtkUBRR6ZXMWE5/NmjpAnF7vG8s47v/9R1Yoi2uA30ItaS763+ lgMfbY7XSWzvQn/PEwhThn0tLKPuru9dBlviP8b7HTe82FWiHNHs27xeNuhQpFH9+uvWsYCobnzb2 60OHOjWZSz3yV0f9qGNKsciSFCEwtKTJzwvrXJjendA6VWr33eMGtkzGwKOpKh8qRmjihzTrDJjsw b04BQNAA==; Received: from [2001:8b0:10b:1:4a2a:e3ff:fe14:8625] (helo=u3832b3a9db3152.ant.amazon.com) by casper.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1oLLRK-00F6WU-NC; Tue, 09 Aug 2022 09:22:18 +0000 Message-ID: Subject: Re: [PATCH v3 2/2] KVM: x86/xen: Stop Xen timer before changing IRQ From: David Woodhouse To: Coleman Dietsch , kvm@vger.kernel.org Cc: Sean Christopherson , Paolo Bonzini , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H . Peter Anvin" , linux-kernel@vger.kernel.org, skhan@linuxfoundation.org, Pavel Skripkin , linux-kernel-mentees@lists.linuxfoundation.org, stable@vger.kernel.org, syzbot+e54f930ed78eb0f85281@syzkaller.appspotmail.com Date: Tue, 09 Aug 2022 10:22:17 +0100 In-Reply-To: <20220808190607.323899-3-dietschc@csp.edu> References: <20220808190607.323899-2-dietschc@csp.edu> <20220808190607.323899-3-dietschc@csp.edu> Content-Type: multipart/signed; micalg="sha-256"; protocol="application/pkcs7-signature"; boundary="=-/TQtfNz4K8qioE8Mme7a" User-Agent: Evolution 3.36.5-0ubuntu1 MIME-Version: 1.0 X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org. See http://www.infradead.org/rpr.html Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org --=-/TQtfNz4K8qioE8Mme7a Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Mon, 2022-08-08 at 14:06 -0500, Coleman Dietsch wrote: > Stop Xen timer (if it's running) prior to changing the IRQ vector and > potentially (re)starting the timer. Changing the IRQ vector while the > timer is still running can result in KVM injecting a garbage event, e.g. > vm_xen_inject_timer_irqs() could see a non-zero xen.timer_pending from > a previous timer but inject the new xen.timer_virq. Hm, wasn't that already addressed in the first patch I saw, which just called kvm_xen_stop_timer() unconditionally before (possibly) setting it up again? --=-/TQtfNz4K8qioE8Mme7a Content-Type: application/pkcs7-signature; name="smime.p7s" Content-Disposition: attachment; filename="smime.p7s" Content-Transfer-Encoding: base64 MIAGCSqGSIb3DQEHAqCAMIACAQExDzANBglghkgBZQMEAgEFADCABgkqhkiG9w0BBwEAAKCCEkQw ggYQMIID+KADAgECAhBNlCwQ1DvglAnFgS06KwZPMA0GCSqGSIb3DQEBDAUAMIGIMQswCQYDVQQG EwJVUzETMBEGA1UECBMKTmV3IEplcnNleTEUMBIGA1UEBxMLSmVyc2V5IENpdHkxHjAcBgNVBAoT FVRoZSBVU0VSVFJVU1QgTmV0d29yazEuMCwGA1UEAxMlVVNFUlRydXN0IFJTQSBDZXJ0aWZpY2F0 aW9uIEF1dGhvcml0eTAeFw0xODExMDIwMDAwMDBaFw0zMDEyMzEyMzU5NTlaMIGWMQswCQYDVQQG EwJHQjEbMBkGA1UECBMSR3JlYXRlciBNYW5jaGVzdGVyMRAwDgYDVQQHEwdTYWxmb3JkMRgwFgYD VQQKEw9TZWN0aWdvIExpbWl0ZWQxPjA8BgNVBAMTNVNlY3RpZ28gUlNBIENsaWVudCBBdXRoZW50 aWNhdGlvbiBhbmQgU2VjdXJlIEVtYWlsIENBMIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKC 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