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 lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (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 9770EC433FE for ; Tue, 4 Oct 2022 13:22:58 +0000 (UTC) Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4Mhdg51jKhz3drp for ; Wed, 5 Oct 2022 00:22:57 +1100 (AEDT) Received: from gandalf.ozlabs.org (gandalf.ozlabs.org [150.107.74.76]) (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 4MhdfR2X0hz2xHw for ; Wed, 5 Oct 2022 00:22:23 +1100 (AEDT) Received: from authenticated.ozlabs.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by mail.ozlabs.org (Postfix) with ESMTPSA id 4MhdfN4svqz4xGj; Wed, 5 Oct 2022 00:22:20 +1100 (AEDT) From: Michael Ellerman To: Fabiano Rosas , linuxppc-dev@lists.ozlabs.org In-Reply-To: <20220816222517.1916391-1-farosas@linux.ibm.com> References: <20220816222517.1916391-1-farosas@linux.ibm.com> Subject: Re: [PATCH] KVM: PPC: Book3S HV: Fix decrementer migration Message-Id: <166488970203.778266.13672388386206891818.b4-ty@ellerman.id.au> Date: Wed, 05 Oct 2022 00:21:42 +1100 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit 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: kvm-ppc@vger.kernel.org, npiggin@gmail.com Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Tue, 16 Aug 2022 19:25:17 -0300, Fabiano Rosas wrote: > We used to have a workaround[1] for a hang during migration that was > made ineffective when we converted the decrementer expiry to be > relative to guest timebase. > > The point of the workaround was that in the absence of an explicit > decrementer expiry value provided by userspace during migration, KVM > needs to initialize dec_expires to a value that will result in an > expired decrementer after subtracting the current guest timebase. That > stops the vcpu from hanging after migration due to a decrementer > that's too large. > > [...] Applied to powerpc/topic/ppc-kvm. [1/1] KVM: PPC: Book3S HV: Fix decrementer migration https://git.kernel.org/powerpc/c/0a5bfb824a6ea35e54b7e5ac6f881beea5e309d2 cheers