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.gnu.org (lists.gnu.org [209.51.188.17]) (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 27C98C83F25 for ; Mon, 21 Jul 2025 16:35:40 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1udtJ3-0005je-K2; Mon, 21 Jul 2025 12:24:06 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1udtIG-0003fM-MX for qemu-devel@nongnu.org; Mon, 21 Jul 2025 12:23:13 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1udtIE-0001RT-4q for qemu-devel@nongnu.org; Mon, 21 Jul 2025 12:23:11 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1753114989; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=5HMbXVPwEREx4z0xNHGKAjtCskhCG3OzH+66bN8KWJ0=; b=DsT3WMG9rKBYq3TwUM8gAkanELNzVOiDlw9y3U4Tc+UX+hv+YZpmv2YEHcBFhffn6bOhrL mEg/O9kWszIrA/PeLmgWc6uxdZO8WT/tpaK1nkuceReWKFLuV7csPvQTVxQ1nUWWDcoffN VUS9fOsp0VNlt1HgwbOZbyzeGoEhEpE= Received: from mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-378-J1ls4oRrPLCueQf2Kr5OMw-1; Mon, 21 Jul 2025 12:23:05 -0400 X-MC-Unique: J1ls4oRrPLCueQf2Kr5OMw-1 X-Mimecast-MFC-AGG-ID: J1ls4oRrPLCueQf2Kr5OMw_1753114983 Received: from mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.17]) (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 mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id D2AE51800365; Mon, 21 Jul 2025 16:23:03 +0000 (UTC) Received: from corto.redhat.com (unknown [10.45.224.19]) by mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 63208195608D; Mon, 21 Jul 2025 16:23:01 +0000 (UTC) From: =?UTF-8?q?C=C3=A9dric=20Le=20Goater?= To: qemu-devel@nongnu.org Cc: Nicholas Piggin , Daniel Henrique Barboza , Glenn Miles , Michael Kowal , Caleb Schlossin , Gautam Menghani , =?UTF-8?q?C=C3=A9dric=20Le=20Goater?= Subject: [PULL 09/50] ppc/xive2: Fix irq preempted by lower priority group irq Date: Mon, 21 Jul 2025 18:21:52 +0200 Message-ID: <20250721162233.686837-10-clg@redhat.com> In-Reply-To: <20250721162233.686837-1-clg@redhat.com> References: <20250721162233.686837-1-clg@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.0 on 10.30.177.17 Received-SPF: pass client-ip=170.10.133.124; envelope-from=clg@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -29 X-Spam_score: -3.0 X-Spam_bar: --- X-Spam_report: (-3.0 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.926, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.001, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org From: Glenn Miles A problem was seen where uart interrupts would be lost resulting in the console hanging. Traces showed that a lower priority interrupt was preempting a higher priority interrupt, which would result in the higher priority interrupt never being handled. The new interrupt's priority was being compared against the CPPR (Current Processor Priority Register) instead of the PIPR (Post Interrupt Priority Register), as was required by the XIVE spec. This allowed for a window between raising an interrupt and ACK'ing the interrupt where a lower priority interrupt could slip in. Fixes: 26c55b99418 ("ppc/xive2: Process group backlog when updating the CPPR") Signed-off-by: Glenn Miles Reviewed-by: Nicholas Piggin Reviewed-by: Michael Kowal Reviewed-by: Caleb Schlossin Tested-by: Gautam Menghani Link: https://lore.kernel.org/qemu-devel/20250512031100.439842-10-npiggin@gmail.com Signed-off-by: Cédric Le Goater --- hw/intc/xive2.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/hw/intc/xive2.c b/hw/intc/xive2.c index edf5d9eb94cb..36e842f041e5 100644 --- a/hw/intc/xive2.c +++ b/hw/intc/xive2.c @@ -1283,7 +1283,7 @@ bool xive2_tm_irq_precluded(XiveTCTX *tctx, int ring, uint8_t priority) * priority to know if the thread can take the interrupt now or if * it is precluded. */ - if (priority < alt_regs[TM_CPPR]) { + if (priority < alt_regs[TM_PIPR]) { return false; } return true; -- 2.50.1