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 mm01.cs.columbia.edu (mm01.cs.columbia.edu [128.59.11.253]) by smtp.lore.kernel.org (Postfix) with ESMTP id E7714C54EE9 for ; Tue, 20 Sep 2022 18:09:24 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 561E94B600; Tue, 20 Sep 2022 14:09:24 -0400 (EDT) X-Virus-Scanned: at lists.cs.columbia.edu Authentication-Results: mm01.cs.columbia.edu (amavisd-new); dkim=softfail (fail, message has been altered) header.i=@kernel.org Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id dY3wPFw-bC7i; Tue, 20 Sep 2022 14:09:23 -0400 (EDT) Received: from mm01.cs.columbia.edu (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 490F34B630; Tue, 20 Sep 2022 14:09:23 -0400 (EDT) Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 1578D4B600 for ; Tue, 20 Sep 2022 14:09:22 -0400 (EDT) X-Virus-Scanned: at lists.cs.columbia.edu Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id rczGh18v80J1 for ; Tue, 20 Sep 2022 14:09:21 -0400 (EDT) Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by mm01.cs.columbia.edu (Postfix) with ESMTPS id DCCD14B24C for ; Tue, 20 Sep 2022 14:09:20 -0400 (EDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 9F980B82BDE; Tue, 20 Sep 2022 18:09:19 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E6ABFC433D6; Tue, 20 Sep 2022 18:09:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1663697358; bh=IIE2Zez7/a1Qc1VfKvs+5cgbTBSAcI81MQ0uNGej81k=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=pMCbSfXW0auMJ8qdBUOJUWWMcdlqjby77wNDSZrfbtznHTzJrnkXJ7mVuJpWMKdoE X6r3WHJkLHyB0R4AL6RNcgP/DxYgyHsrRRYn/7LbQzIhYi2gcVxGaKAj7xKI1L79Xe fVzEJ5uMMx3wlV6fcEOie4HC7o+aT3kyBidHfIzDsKrwxLti++kAl/FoJTbzRSBjm6 DsL1h/QBIc97Xu8S63i4vZZJ5YZ8cO8byyPcsP1UWgwUYMtgSFdezOr8mHSTI6jFqd VDnLxBQykRWIBdW0UKjtOd3pTOryhACTeZbYChUdhuqAJ+VUqcyNSfSTZCiI0lVyQ8 YKSoAJjFqVtxw== Date: Tue, 20 Sep 2022 19:09:15 +0100 From: Mark Brown To: Marc Zyngier Subject: Re: [PATCH v3 2/7] arm64/fpsimd: Track the saved FPSIMD state type separately to TIF_SVE Message-ID: References: <20220815225529.930315-1-broonie@kernel.org> <20220815225529.930315-3-broonie@kernel.org> <87y1uej7dm.wl-maz@kernel.org> MIME-Version: 1.0 In-Reply-To: <87y1uej7dm.wl-maz@kernel.org> X-Cookie: One FISHWICH coming up!! Cc: Catalin Marinas , Zhang Lei , Andre Przywara , Will Deacon , kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org X-BeenThere: kvmarm@lists.cs.columbia.edu X-Mailman-Version: 2.1.14 Precedence: list List-Id: Where KVM/ARM decisions are made List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: multipart/mixed; boundary="===============1899766398920930825==" Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu --===============1899766398920930825== Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="F2TYRAB+02knW1Ru" Content-Disposition: inline --F2TYRAB+02knW1Ru Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Tue, Sep 20, 2022 at 06:14:13PM +0100, Marc Zyngier wrote: > Mark Brown wrote: > > When we save the state for the floating point registers this can be done > > in the form visible through either the FPSIMD V registers or the SVE Z and > > P registers. At present we track which format is currently used based on > > TIF_SVE and the SME streaming mode state but particularly in the SVE case > > this limits our options for optimising things, especially around syscalls. > > Introduce a new enum in thread_struct which explicitly states which format > > is active and keep it up to date when we change it. > > At present we do not use this state except to verify that it has the > > expected value when loading the state, future patches will introduce > > functional changes. > > + enum fp_state fp_type; > Is it a state or a type? Some consistency would help. Also, what does We can bikeshed this either way - the state currently stored is of a particular type. I'll probably go for type. > this represent? Your commit message keeps talking about the FP/SVE > state for the host, but this is obviously a guest-related structure. > How do the two relate? The commit message talks about saving the floating point state in general which is something we do for both the host and the guest. The optimisation cases I am focusing on right now are more on host usage but the complexity with tracking that currently blocks them crosses both host and guest, indeed the biggest improvement overall is probably that tracking the guest state stops requiring us to fiddle with the host task's state which to me at least makes things clearer. --F2TYRAB+02knW1Ru Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEreZoqmdXGLWf4p/qJNaLcl1Uh9AFAmMqAcoACgkQJNaLcl1U h9Dyfgf8DqcSgSpIMFm7ghAZD34enLc6Td4USGjfJ5GqsGTZZvbo9m32uPxEnjDp mmDbT0uo7d1BG2QR1GiHgPQGW6UwgMf1RjG4T1lFi83JknKpUkaOUsDR4PPejUok aQjLxK2rr6FJku55sbPpOo7u4oidNjJDNRlNnLvdVCE1gZmj+nBD+FY77tDw5Y3e 2n8NBwqU6T1B6kEgwgm0siCB19IrZhXfGn1M0u6HLm4IL2h2BGgb8P9dC2yJkteE ZeD/KvVziahNq8ZFb9mqyGEKl9fZzaXEzwSAK5VnPXhEoaWs8vT7jDS1TZEiMG19 hQN9AZJW2bYsKpHx0tEHnfeiDhzaNw== =uRBY -----END PGP SIGNATURE----- --F2TYRAB+02knW1Ru-- --===============1899766398920930825== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ kvmarm mailing list kvmarm@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/kvmarm --===============1899766398920930825==--