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=-2.5 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS, USER_AGENT_MUTT autolearn=ham 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 BA7A9C43381 for ; Wed, 27 Feb 2019 13:50:42 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 83B4720C01 for ; Wed, 27 Feb 2019 13:50:42 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="NFUzrjYi" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 83B4720C01 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=mibmrThsFeSF9Iwr3CvaiVn7i0NqDUH1sDmSZYw1myM=; b=NFUzrjYidJwzYp 3j7QvTiaqSNtDhA/FqBQt45r9D7hGUipE0PNDUSZDVMxqboK0rN7HgTz6KIzhfFm0hpEK2vFNnLvX ASWfOFuiQHdBDjZIBI/WwANH5uQE5jziVNHRy8DbzpOQTQ9QmhrbPirAjLHnEG667UJg5LcmbPGo3 9jqNYbyAF+LNRjTJth3yRW3K/5eR5Pe+TUzV2NEWEiZp1KTY3iWweW7VIG5FALNINSzDh6E+WX/UR 61daVzWxGYYYdbpiZDQKH+/MFmn/pGYppSqKKX93a9DAh+9fXzLxiLutk0MX6w8bcKJqHi4gjehUy U9rRua8JKa38cV7jC26w==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1gyzba-0007IH-RY; Wed, 27 Feb 2019 13:50:38 +0000 Received: from foss.arm.com ([217.140.101.70]) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1gyzbX-0007Hs-PC for linux-arm-kernel@lists.infradead.org; Wed, 27 Feb 2019 13:50:37 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 246FE374; Wed, 27 Feb 2019 05:50:35 -0800 (PST) Received: from e103592.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.72.51.249]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 56DA63F5C1; Wed, 27 Feb 2019 05:50:33 -0800 (PST) Date: Wed, 27 Feb 2019 13:50:30 +0000 From: Dave Martin To: Julien Grall Subject: Re: [PATCH v5 13/26] KVM: arm64/sve: System register context switch and access support Message-ID: <20190227135030.GE3567@e103592.cambridge.arm.com> References: <1550519559-15915-1-git-send-email-Dave.Martin@arm.com> <1550519559-15915-14-git-send-email-Dave.Martin@arm.com> <8a0e6089-b77b-151b-eacd-34ad13f39ac6@arm.com> <20190226170105.GB3567@e103592.cambridge.arm.com> <5a7dc2f4-a6e7-28bb-64d7-4f64424eb5c2@arm.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <5a7dc2f4-a6e7-28bb-64d7-4f64424eb5c2@arm.com> User-Agent: Mutt/1.5.23 (2014-03-12) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190227_055035_818036_90B0F5CA X-CRM114-Status: GOOD ( 22.02 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Okamoto Takayuki , Christoffer Dall , Ard Biesheuvel , Marc Zyngier , Catalin Marinas , Will Deacon , Zhang Lei , kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Wed, Feb 27, 2019 at 12:02:46PM +0000, Julien Grall wrote: > Hi Dave, > > On 2/26/19 5:01 PM, Dave Martin wrote: > >On Tue, Feb 26, 2019 at 04:32:30PM +0000, Julien Grall wrote: > >>On 18/02/2019 19:52, Dave Martin wrote: > >>We seem to already have code for handling invariant registers as well as > >>reading ID register. I guess the only reason you can't use them is because > >>of the check the vcpu is using SVE. > >> > >>However, AFAICT the restrictions callback would prevent you to enter the > >>{get, set}_id if the vCPU does not support SVE. So the check should not be > >>reachable. > > > >Hmmm, those checks were inherited from before this refactoring. > > > >You're right: the checks are now done a common place, so the checks in > >the actual accessors should be redundant. > > > >I could demote them to WARN(), but it may make sense simply to delete > >them. > > I think removing the WARN() would be best as it would avoid to introduce > most of the wrappers for the registers. > > > > >The access_id_aa64zfr0_el1() should still be reachable, since we don't > >have REG_NO_GUEST for this. > > __access_id_reg is taking a boolean to tell whether the register is RAZ or > not. So you probably could re-use it passing !vcpu_has_sve(vcpu). > > It feels to me we would introduce a new restriction to tell whether the > register should be RAZ. Anyway, the new restriction is probably for a > follow-up patch. It's true that we should be able to handle these as regular ID regs in the get()/set() case, when SVE is enabled for the vcpu. I'll have a think about how to reduce the amount of special-case code here maybe we can indeed get of some of these accessors entitely now that access is rejected earlier, in a more generic way. The access() case for this register still has to be custom though; I don't see a trivial solution for that. Cheers ---Dave _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel