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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 1B633C5472F for ; Tue, 27 Aug 2024 17:04:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=MV12ntjo4cxMXNDjQ7ec7Q6W3AL3teSESN1/QLqjjxw=; b=Dthsrni9Wqo3+BNx6GJxskAM7m wTx2fBIWaoPw7sLxoaTWnl2wp4yWs3punkX4Ds/ecUcfpyP2aEtMYD7Qe34i0+z9dV6ki8Gup/byb oL/z5oukJV/870yc3Md4vbpwSsvETT9nDanuGVFSWPjQ7kAD7uzv+w9pQ+fHatGdj94gjuCWYfrtW 5t1HEVCXFYaWpl4kZTZQAMLup25+1YNHwq40XN3ad8ZQYJaIW0lV9L2uchCdWM32tmzRnjmecff9u qzLvjduoN9e6Am4S1V62LGuyXzSLNMYrElgSV4QD+un5FjPadr9cL/KgVCsvuzNS30jWwH7e3DUze wd1sLkSw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1sizcJ-0000000CCyk-2kRe; Tue, 27 Aug 2024 17:04:27 +0000 Received: from out-182.mta0.migadu.com ([2001:41d0:1004:224b::b6]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1sizZC-0000000CBYa-3ALw for linux-arm-kernel@lists.infradead.org; Tue, 27 Aug 2024 17:01:16 +0000 Date: Tue, 27 Aug 2024 10:01:02 -0700 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1724778072; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=MV12ntjo4cxMXNDjQ7ec7Q6W3AL3teSESN1/QLqjjxw=; b=PKS77+tp3JM/UMvuFCxQQnisoTXR7DAgJVmkv+pcVUDEXyzMr29CfF79jnqKuIqnoYWAB2 b172WCEOzib9d3mSliGTuxS0y+aSTiWc0e0lbxebReSkwOXvX+plEEmwVJvPfFbc33z+Za MJ9Bm3AnZaUTqive9F/CmyPRkhz/VCk= X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Oliver Upton To: Marc Zyngier Cc: kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, kvm@vger.kernel.org, James Morse , Suzuki K Poulose , Zenghui Yu , Alexander Potapenko Subject: Re: [PATCH v2 00/11] KVM: arm64: Handle the lack of GICv3 exposed to a guest Message-ID: References: <20240827152517.3909653-1-maz@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240827152517.3909653-1-maz@kernel.org> X-Migadu-Flow: FLOW_OUT X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240827_100115_075628_92885264 X-CRM114-Status: GOOD ( 15.75 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue, Aug 27, 2024 at 04:25:06PM +0100, Marc Zyngier wrote: > It recently appeared that, when running on a GICv3-equipped platform > (which is what non-ancient arm64 HW has), *not* configuring a GICv3 > for the guest could result in less than desirable outcomes. > > We have multiple issues to fix: > > - for registers that *always* trap (the SGI registers) or that *may* > trap (the SRE register), we need to check whether a GICv3 has been > instantiated before acting upon the trap. > > - for registers that only conditionally trap, we must actively trap > them even in the absence of a GICv3 being instantiated, and handle > those traps accordingly. > > - finally, ID registers must reflect the absence of a GICv3, so that > we are consistent. > > This series goes through all these requirements. The main complexity > here is to apply a GICv3 configuration on the host in the absence of a > GICv3 in the guest. This is pretty hackish, but I don't have a much > better solution so far. LGTM, thanks for respinning. Reviewed-by: Oliver Upton -- Thanks, Oliver