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 X-Spam-Level: X-Spam-Status: No, score=-3.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 63894C433DF for ; Mon, 12 Oct 2020 05:50:24 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id B640E2078E for ; Mon, 12 Oct 2020 05:50:23 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=gibson.dropbear.id.au header.i=@gibson.dropbear.id.au header.b="C3H/Kjkn" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B640E2078E Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=gibson.dropbear.id.au Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:34252 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kRqj0-0006kq-NJ for qemu-devel@archiver.kernel.org; Mon, 12 Oct 2020 01:50:22 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:46324) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kRqiB-000606-SH; Mon, 12 Oct 2020 01:49:31 -0400 Received: from ozlabs.org ([203.11.71.1]:33673) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kRqi8-0007Ix-PR; Mon, 12 Oct 2020 01:49:31 -0400 Received: by ozlabs.org (Postfix, from userid 1007) id 4C8nn04GKKz9sT6; Mon, 12 Oct 2020 16:49:24 +1100 (AEDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gibson.dropbear.id.au; s=201602; t=1602481764; bh=5myDoT9glAj6UIQl/rhiWg36DL4weyBKQNx5WXxr/44=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=C3H/Kjkn7nz+f2bicfCqvKL0Nks0AGD1K2SxU26O+BH9CSfSPX4UWoWu9KEElrMcw pKXBMnnrqcBZ84O9COeyhjbNQfKPWfWOMhoZ9o0ThR93wJ92JWuoUwLfJNSqBB+B+P a4QkhopqRN1TBY50ltNvJKLQoW+E5bryXzbGxvI4= Date: Mon, 12 Oct 2020 16:38:46 +1100 From: David Gibson To: =?iso-8859-1?Q?C=E9dric?= Le Goater Subject: Re: [PATCH v2 0/6] spapr/xive: Activate StoreEOI in P10 compat guests Message-ID: <20201012053846.GE4787@yekko.fritz.box> References: <20201005165147.526426-1-clg@kaod.org> <20201009002326.GB1025389@yekko.fritz.box> <5a3af480-8e84-ddb8-e40e-e3050f6c2978@kaod.org> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="KdquIMZPjGJQvRdI" Content-Disposition: inline In-Reply-To: <5a3af480-8e84-ddb8-e40e-e3050f6c2978@kaod.org> Received-SPF: pass client-ip=203.11.71.1; envelope-from=dgibson@ozlabs.org; helo=ozlabs.org X-detected-operating-system: by eggs.gnu.org: First seen = 2020/10/12 01:33:58 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -17 X-Spam_score: -1.8 X-Spam_bar: - X-Spam_report: (-1.8 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, HEADER_FROM_DIFFERENT_DOMAINS=0.25, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Gustavo Romero , qemu-ppc@nongnu.org, qemu-devel@nongnu.org, Greg Kurz Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" --KdquIMZPjGJQvRdI Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, Oct 09, 2020 at 07:57:32AM +0200, C=E9dric Le Goater wrote: > On 10/9/20 2:23 AM, David Gibson wrote: > > On Mon, Oct 05, 2020 at 06:51:41PM +0200, C=E9dric Le Goater wrote: > >> Hello, > >> > >> When an interrupt has been handled, the OS notifies the interrupt > >> controller with an EOI sequence. On the XIVE interrupt controller > >> (POWER9 and POWER10), this can be done with a load or a store > >> operation on the ESB interrupt management page of the interrupt. The > >> StoreEOI operation has less latency and improves interrupt handling > >> performance but it was deactivated during the POWER9 DD2.0 time-frame > >> because of ordering issues. POWER9 systems use the LoadEOI instead. > >> POWER10 has fixed the issue with a special load command which enforces > >> Load-after-Store ordering and StoreEOI can be safely used. > >=20 > > Do you mean that ordering is *always* enforced on P10? Or it's a > > special form of load that has the ordering? >=20 > It's a special form of load that has the ordering, only on available=20 > on P10. It's a no-op on P9. no-op as in the load will have regular semantics, or as in the whole load won't do anything? I assume this meanse XIVE code needs to be updated to use that special load for all accesses to XIVE registers...=20 > Linux commit b1f9be9392f0 ("powerpc/xive: Enforce load-after-store =20 > ordering when StoreEOI is active") introduced the Load-after-Store=20 > ordering offset and P10 support was added in the same 5.8 release. =2E. which I guess this does? > This is why StoreEOI should be advertised on P10 compat kernels only.=20 > I would have preferred to introduce some extra CAS bits. that would=20 > have been cleaner than mix the two. Ok. > The basic requirement is to advertise StoreEOI when the CPU compat > allows it. I have used the capabilities to toggle the feature on/off. > It seemed a clean way to cover all the extra needs :=20 >=20 > - switch it off on P10 if needed > - switch it on on P9 for tests Ok, seems reasonable > > Also, weirdly, despite the series being addressed to me, only some of > > the patches ended up in my inbox, rather than the list folder :/. >=20 >=20 > Yes. I have received a few ot these :=20 > =20 > The original message was received at Mon, 5 Oct 2020 12:51:56 -0400 > from m0098419.ppops.net [127.0.0.1] >=20 > ----- The following addresses had permanent fatal errors ----- > Drat, I guess ozlabs.org fell off the net for a while. --=20 David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/~dgibson --KdquIMZPjGJQvRdI Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEEdfRlhq5hpmzETofcbDjKyiDZs5IFAl+D6+UACgkQbDjKyiDZ s5L8rBAA1jUJoHK/udp5MMWNfZ8SztIMFgni7muInfQ5eHvl3ZW0rmCgqPYxTR35 Hgsc3gMwgVmWuBLEMXrkUhIuP+q5PDDUPKxkjsNFS3tdoKyU7KBMxJ9FVQAWGptx k21lBxRt6ORJrYUysmEuNJp4DW5RIxwLXe1i/UzMC+cmx58Ca3L4AD8/8nYjwnVM DzhFw9RZ0L7NfH+dKOoN4TqVADLdSPW+t46TsGXBr6OzYouH+I2fbrvQvaCEXodS EbEUZglW9sMFDaVOlqxLBI3WM483Q7F6KG6DE2KKJ6MnNHVkIkhrqo67Dq2OoCzS T2QXpdBdKsJ1oc3ztmBR8XEaiObUAYdxKKNL/RLzp4pqU7bE2oh0D9728h1EXLrI JoPx7dJ9ojEaZB8z2QuuFJGs3RG6LbHkfPajK7JP5xeNo1A8DHfyxtWeGAhlKQhO CBs+aujpsUevpHxBaO1DJ0kH7DcLF6kuzmYEvdBIr2zSM4VILrEqcj5D9JJgXryk WsBFCjbAzgU4530akOviIkwE/4foYaXNbaBIIX3mhV2g8VD2nsr7Q+C8OqFAp827 oIiPyGGNVOTm9prnQKI903d7ZjyhUHtejk3O+6ydYcFKxh3G9SzZ2+84Lj9TjJjM JFAPokNFE5SKmvRxIiHu7trT9xgw0C/YUqnFm4zAT2j7Tw7eWJ8= =vnGP -----END PGP SIGNATURE----- --KdquIMZPjGJQvRdI--