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=-8.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 264CDC3A59D for ; Thu, 22 Aug 2019 10:48:50 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (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 77A24206B7 for ; Thu, 22 Aug 2019 10:48:49 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 77A24206B7 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ellerman.id.au Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from bilbo.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 46Dh8v3tTZzDrVT for ; Thu, 22 Aug 2019 20:48:47 +1000 (AEST) Received: from ozlabs.org (bilbo.ozlabs.org [203.11.71.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 46Dh6H1YX4zDqHX for ; Thu, 22 Aug 2019 20:46:31 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=ellerman.id.au Received: by ozlabs.org (Postfix, from userid 1034) id 46Dh6F6clVz9sN6; Thu, 22 Aug 2019 20:46:29 +1000 (AEST) X-powerpc-patch-notification: thanks X-powerpc-patch-commit: 237aed48c642328ff0ab19b63423634340224a06 In-Reply-To: <20190806172538.5087-1-clg@kaod.org> To: =?utf-8?q?C=C3=A9dric_Le_Goater?= , Paul Mackerras From: Michael Ellerman Subject: Re: [PATCH] KVM: PPC: Book3S HV: XIVE: Free escalation interrupts before disabling the VP Message-Id: <46Dh6F6clVz9sN6@ozlabs.org> Date: Thu, 22 Aug 2019 20:46:29 +1000 (AEST) X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linuxppc-dev@lists.ozlabs.org, kvm-ppc@vger.kernel.org, kvm@vger.kernel.org, =?utf-8?q?C=C3=A9dric_Le?= =?utf-8?q?_Goater?= Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Tue, 2019-08-06 at 17:25:38 UTC, =?utf-8?q?C=C3=A9dric_Le_Goater?= wrote: > When a vCPU is brought done, the XIVE VP is first disabled and then > the event notification queues are freed. When freeing the queues, we > check for possible escalation interrupts and free them also. > > But when a XIVE VP is disabled, the underlying XIVE ENDs also are > disabled in OPAL. When an END is disabled, its ESB pages (ESn and ESe) > are disabled and loads return all 1s. Which means that any access on > the ESB page of the escalation interrupt will return invalid values. > > When an interrupt is freed, the shutdown handler computes a 'saved_p' > field from the value returned by a load in xive_do_source_set_mask(). > This value is incorrect for escalation interrupts for the reason > described above. > > This has no impact on Linux/KVM today because we don't make use of it > but we will introduce in future changes a xive_get_irqchip_state() > handler. This handler will use the 'saved_p' field to return the state > of an interrupt and 'saved_p' being incorrect, softlockup will occur. > > Fix the vCPU cleanup sequence by first freeing the escalation > interrupts if any, then disable the XIVE VP and last free the queues. > > Signed-off-by: Cédric Le Goater Applied to powerpc topic/ppc-kvm, thanks. https://git.kernel.org/powerpc/c/237aed48c642328ff0ab19b63423634340224a06 cheers