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 C6917C25B0C for ; Tue, 9 Aug 2022 14:36:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243189AbiHIOg1 (ORCPT ); Tue, 9 Aug 2022 10:36:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56840 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231768AbiHIOgY (ORCPT ); Tue, 9 Aug 2022 10:36:24 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 247E3B489; Tue, 9 Aug 2022 07:36:23 -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=n0f6MfKve4+T6C9VP9HMAipX8D+7c7oc6TJ/Jy1pTzc=; b=WDXRQ48l9l2XSSHP/yjrfk+EIZ +LRNZUgWIJIdvnossZoUyopopTj6AbW9miLSlGl6hmQO6BJ9HXUcGYupNPLmse3yxMnj/sPxUZ8Qm bUWxLRuRkwDPTB0tuldM6qGKjBAsi7NMeSY/HUFE1NKPJHa092RWeIqnQo7g+duXJKfSAnmnoykbp X2F6pVk0pFhOzPwrm7EIaDapXUd2wExWpdzErx3bVNYry674kb2rITsGla23GqJgecFKnkXtWvhyG OFVyJbuBk7nN1jQfIj9TAm+78HQn09R+nDJn3wxNO/iQIeVFt9CCUUz9+o3QKijwdP7woyulBaEKd uSpz9HrQ==; 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 1oLQL9-00FTUv-Gj; Tue, 09 Aug 2022 14:36:15 +0000 Message-ID: <8e99bcfb8dd3a8c2ff8fa9d88b77490aac83cd10.camel@infradead.org> Subject: Re: [PATCH v3 2/2] KVM: x86/xen: Stop Xen timer before changing IRQ From: David Woodhouse To: Paolo Bonzini , Sean Christopherson Cc: Coleman Dietsch , kvm@vger.kernel.org, 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, metikaya Date: Tue, 09 Aug 2022 15:36:13 +0100 In-Reply-To: <953d2e99-ed1a-384d-6d3a-0f656a243f82@redhat.com> References: <20220808190607.323899-2-dietschc@csp.edu> <20220808190607.323899-3-dietschc@csp.edu> <43e258cc-71ac-bde4-d1f8-9eb9519928d3@redhat.com> <4fc1371b83001b4eed1617c37bec6b9d007e45c2.camel@infradead.org> <0b5dcab333906f166fcdbc296373cc5e08bec79f.camel@infradead.org> <953d2e99-ed1a-384d-6d3a-0f656a243f82@redhat.com> Content-Type: multipart/signed; micalg="sha-256"; protocol="application/pkcs7-signature"; boundary="=-MmsHTjnrl23FvL2TyIKY" 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 --=-MmsHTjnrl23FvL2TyIKY Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Tue, 2022-08-09 at 16:31 +0200, Paolo Bonzini wrote: > On 8/9/22 16:16, David Woodhouse wrote: > > I find the new version a bit harder to follow, with its init-then-stop- > > then-start logic: > >=20 > > case KVM_XEN_VCPU_ATTR_TYPE_TIMER: > > if (data->u.timer.port && > > data->u.timer.priority !=3D KVM_IRQ_ROUTING_XEN_EVTCHN_PRIO_2LEVE= L) { > > r =3D -EINVAL; > > break; > > } > >=20 > > if (!vcpu->arch.xen.timer.function) > > kvm_xen_init_timer(vcpu); > >=20 > > /* Stop the timer (if it's running) before changing the vector */ > > kvm_xen_stop_timer(vcpu); > > vcpu->arch.xen.timer_virq =3D data->u.timer.port; >=20 >=20 > I think this is fine, if anything the kvm_xen_stop_timer() call could be= =20 > placed in an "else" but I'm leaning towards applying this version of the= =20 > patch. Fair enough. It should definitely work, and is functionally identical in all interesting cases. In that case, for both of the patches from this v3 series: Acked-by: David Woodhouse Thanks. --=-MmsHTjnrl23FvL2TyIKY 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 AQEAyjztlApB/975Rrno1jvm2pK/KxBOqhq8gr2+JhwpKirSzZxQgT9tlC7zl6hn1fXjSo5MqXUf 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