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 4098EC87FCD for ; Mon, 21 Jul 2025 16:42:47 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1udtKX-0002Hr-AB; Mon, 21 Jul 2025 12:25:33 -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 1udtJH-0006KM-NY for qemu-devel@nongnu.org; Mon, 21 Jul 2025 12:24:19 -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 1udtJF-0001gJ-LH for qemu-devel@nongnu.org; Mon, 21 Jul 2025 12:24:15 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1753115053; 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=c5EInsA9TzgflXUCHGjdBwKqce/hjrYzL5PyDmrY3Aw=; b=EGbAmlFBsuluMHTlLydLObmiKweEY38gCx3iKGmV0RDHhh9g7k7WziXHmTjidGlqBmW1XN LBAAbNxKJL9cjGBKFhM5rtHmlIp6+4QL9W8Z1gIoksFpxy4DwnnxW7LQH6ZNRcE7loFoas tanxZGlSoAE4bD/j3QUrqzxIr25n+Y0= Received: from mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-6-GIwGHqdPPWCBg-Fml2p9uQ-1; Mon, 21 Jul 2025 12:24:07 -0400 X-MC-Unique: GIwGHqdPPWCBg-Fml2p9uQ-1 X-Mimecast-MFC-AGG-ID: GIwGHqdPPWCBg-Fml2p9uQ_1753115046 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-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 5C0B9195608C; Mon, 21 Jul 2025 16:24:06 +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 28F4D195608D; Mon, 21 Jul 2025 16:24:03 +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 , Gautam Menghani , =?UTF-8?q?C=C3=A9dric=20Le=20Goater?= Subject: [PULL 31/50] ppc/xive: Fix high prio group interrupt being preempted by low prio VP Date: Mon, 21 Jul 2025 18:22:14 +0200 Message-ID: <20250721162233.686837-32-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: Nicholas Piggin xive_tctx_pipr_present() as implemented with xive_tctx_pipr_update() causes VP-directed (group==0) interrupt to be presented in PIPR and NSR despite being a lower priority than the currently presented group interrupt. This must not happen. The IPB bit should record the low priority VP interrupt, but PIPR and NSR must not present the lower priority interrupt. Signed-off-by: Nicholas Piggin Reviewed-by: Glenn Miles Reviewed-by: Michael Kowal Tested-by: Gautam Menghani Link: https://lore.kernel.org/qemu-devel/20250512031100.439842-32-npiggin@gmail.com Signed-off-by: Cédric Le Goater --- hw/intc/xive.c | 18 +++++++++++++++++- 1 file changed, 17 insertions(+), 1 deletion(-) diff --git a/hw/intc/xive.c b/hw/intc/xive.c index 038c35846d94..7110cf45d74f 100644 --- a/hw/intc/xive.c +++ b/hw/intc/xive.c @@ -228,7 +228,23 @@ void xive_tctx_pipr_update(XiveTCTX *tctx, uint8_t ring, uint8_t priority, void xive_tctx_pipr_present(XiveTCTX *tctx, uint8_t ring, uint8_t priority, uint8_t group_level) { - xive_tctx_pipr_update(tctx, ring, priority, group_level); + /* HV_POOL ring uses HV_PHYS NSR, CPPR and PIPR registers */ + uint8_t alt_ring = (ring == TM_QW2_HV_POOL) ? TM_QW3_HV_PHYS : ring; + uint8_t *aregs = &tctx->regs[alt_ring]; + uint8_t *regs = &tctx->regs[ring]; + uint8_t pipr = xive_priority_to_pipr(priority); + + if (group_level == 0) { + regs[TM_IPB] |= xive_priority_to_ipb(priority); + if (pipr >= aregs[TM_PIPR]) { + /* VP interrupts can come here with lower priority than PIPR */ + return; + } + } + g_assert(pipr <= xive_ipb_to_pipr(regs[TM_IPB])); + g_assert(pipr < aregs[TM_PIPR]); + aregs[TM_PIPR] = pipr; + xive_tctx_notify(tctx, ring, group_level); } /* -- 2.50.1