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 75206C54754 for ; Thu, 15 May 2025 15:48:20 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1uFan8-0000my-MA; Thu, 15 May 2025 11:46:38 -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 1uFamF-00082Q-KW; Thu, 15 May 2025 11:45:44 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1uFam4-0006U5-Or; Thu, 15 May 2025 11:45:43 -0400 Received: from pps.filterd (m0360072.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.18.1.2/8.18.1.2) with ESMTP id 54FCg6LI002316; Thu, 15 May 2025 15:45:30 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=cc :content-transfer-encoding:content-type:date:from:in-reply-to :message-id:mime-version:references:reply-to:subject:to; s=pp1; bh=oSt+N1lu/Ph9YEJoXpM25zKAE7994l+m0uALbFqfXHI=; b=WdtecRkLMw8P Z8y2bRyOrNKLN17lnJWZvU+ZG++0O4ryVd7f2PWMJxgrVD/jC+WZRPGkrJSqP7wY 42OxGg2S1BeQIIqEd6B8p/KYjkDVPnxhwbAiZgYeiGh8ZlPxvMtDOWDfiQjsstjq cNpSuj9aWwLMb7cOYEskgTAuEIj4z5ZQw7AF6Ukkkn5GwGKspze6sKHiLZV+oy+8 0tJRpZwoat6J1Vdiw2mBy4gwyjVQ/x1XKkaly7g9lCfj5KV3fjCEzneYptA2YCK8 CUAE5HsyXtyGu7EdvbCNB6jN9/UKrKA+ytG/c7+bpia6bUQ7qX88Q6XJi61jtmEs Z+LI/pfKwQ== Received: from pps.reinject (localhost [127.0.0.1]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 46n0v6ndx9-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 15 May 2025 15:45:30 +0000 (GMT) Received: from m0360072.ppops.net (m0360072.ppops.net [127.0.0.1]) by pps.reinject (8.18.0.8/8.18.0.8) with ESMTP id 54FFjTwe019016; Thu, 15 May 2025 15:45:29 GMT Received: from ppma12.dal12v.mail.ibm.com (dc.9e.1632.ip4.static.sl-reverse.com [50.22.158.220]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 46n0v6ndx6-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 15 May 2025 15:45:29 +0000 (GMT) Received: from pps.filterd (ppma12.dal12v.mail.ibm.com [127.0.0.1]) by ppma12.dal12v.mail.ibm.com (8.18.1.2/8.18.1.2) with ESMTP id 54FEOTig015329; Thu, 15 May 2025 15:45:29 GMT Received: from smtprelay06.wdc07v.mail.ibm.com ([172.16.1.73]) by ppma12.dal12v.mail.ibm.com (PPS) with ESMTPS id 46mbfq30ep-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 15 May 2025 15:45:29 +0000 Received: from smtpav02.wdc07v.mail.ibm.com (smtpav02.wdc07v.mail.ibm.com [10.39.53.229]) by smtprelay06.wdc07v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 54FFjR9o25756306 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 15 May 2025 15:45:27 GMT Received: from smtpav02.wdc07v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 3AEF858059; Thu, 15 May 2025 15:45:27 +0000 (GMT) Received: from smtpav02.wdc07v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id A8EA258058; Thu, 15 May 2025 15:45:26 +0000 (GMT) Received: from mambor8.rchland.ibm.com (unknown [9.10.239.198]) by smtpav02.wdc07v.mail.ibm.com (Postfix) with ESMTP; Thu, 15 May 2025 15:45:26 +0000 (GMT) Message-ID: <12549968b1d9a0a89b32900b3fc8c4a574a28906.camel@linux.ibm.com> Subject: Re: [PATCH 12/50] ppc/xive2: Set CPPR delivery should account for group priority From: Miles Glenn To: Nicholas Piggin , qemu-ppc@nongnu.org Cc: qemu-devel@nongnu.org, =?ISO-8859-1?Q?Fr=E9d=E9ric?= Barrat , Michael Kowal , Caleb Schlossin Date: Thu, 15 May 2025 10:45:26 -0500 In-Reply-To: <20250512031100.439842-13-npiggin@gmail.com> References: <20250512031100.439842-1-npiggin@gmail.com> <20250512031100.439842-13-npiggin@gmail.com> Organization: IBM Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.28.5 (3.28.5-27.el8_10) Mime-Version: 1.0 Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Authority-Analysis: v=2.4 cv=IqAecK/g c=1 sm=1 tr=0 ts=68260c1a cx=c_pps a=bLidbwmWQ0KltjZqbj+ezA==:117 a=bLidbwmWQ0KltjZqbj+ezA==:17 a=IkcTkHD0fZMA:10 a=dt9VzEwgFbYA:10 a=pGLkceISAAAA:8 a=zSV6phptauE46_GIRisA:9 a=QEXdDO2ut3YA:10 X-Proofpoint-ORIG-GUID: j93Hfu676Q3HpO1RJPJYyrKOxQedT-KB X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUwNTE1MDE1NSBTYWx0ZWRfXzB7WH5U8VGUP WdKSdzRdh/QuRrx1G0z6Gq08kOg4TyQ7el1mf5BlVTsKyy7trcDSFeSca32qN9T6AUl90nvYRPp nwfsQTaaGglDInbB77bIqH3283JkfypLpv0dvY4pPxmSb7bTpg5zizmHoGaaoWME2ZT6pcWAO3P cC3WtdDgx5J9Th90dJ1oUhwLY1TWGksiasV5WymwnMTJlk4yNNTWRITHVwWPQgPdZ7LSyA3q+iI 7ND5rGdev2vLsTAOHwCAEP17kZfdfB00s/E+ofNikc6TgFp1OWXoJM8havlCkxYKo4qkl1rruYw FfkQHEioBxyiE1WYQEX8EvCuCnHulDU46Fe3ONHMXZmueQapi8Wt3VJAkJ52aZbfG8+zWGoPBXn XsRttxSp0BL6pm7liw1dbmzO+qYIQUPmKKRgOlE0u/ZpjJopZyOHx3tLD1fjs1sfTVqpIhPC X-Proofpoint-GUID: yvXyE6cKdRwapzRaeOAP_fJZVL-PHSSZ X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1099,Hydra:6.0.736,FMLib:17.12.80.40 definitions=2025-05-15_06,2025-05-15_01,2025-03-28_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 mlxscore=0 malwarescore=0 adultscore=0 lowpriorityscore=0 phishscore=0 impostorscore=0 priorityscore=1501 clxscore=1015 spamscore=0 mlxlogscore=999 bulkscore=0 suspectscore=0 classifier=spam authscore=0 authtc=n/a authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.19.0-2505070000 definitions=main-2505150155 Received-SPF: pass client-ip=148.163.158.5; envelope-from=milesg@linux.ibm.com; helo=mx0b-001b2d01.pphosted.com X-Spam_score_int: -26 X-Spam_score: -2.7 X-Spam_bar: -- X-Spam_report: (-2.7 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_VALIDITY_CERTIFIED_BLOCKED=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, SPF_HELO_NONE=0.001, T_SPF_TEMPERROR=0.01 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: , Reply-To: milesg@linux.ibm.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Mon, 2025-05-12 at 13:10 +1000, Nicholas Piggin wrote: > The group interrupt delivery flow selects the group backlog scan if > LSMFB < IPB, but that scan may find an interrupt with a priority >= > IPB. In that case, the VP-direct interrupt should be chosen. This > extends to selecting the lowest prio between POOL and PHYS rings. > > Implement this just by re-starting the selection logic if the > backlog irq was not found or priority did not match LSMFB (LSMFB > is updated so next time around it would see the right value and > not loop infinitely). > > Signed-off-by: Nicholas Piggin > --- > hw/intc/xive2.c | 32 ++++++++++++++++++++++---------- > 1 file changed, 22 insertions(+), 10 deletions(-) > > diff --git a/hw/intc/xive2.c b/hw/intc/xive2.c > index 8ede95b671..de139dcfbf 100644 > --- a/hw/intc/xive2.c > +++ b/hw/intc/xive2.c > @@ -939,7 +939,7 @@ static void xive2_tctx_set_cppr(XiveTCTX *tctx, uint8_t ring, uint8_t cppr) > { > uint8_t *regs = &tctx->regs[ring]; > Xive2Router *xrtr = XIVE2_ROUTER(tctx->xptr); > - uint8_t old_cppr, backlog_prio, first_group, group_level = 0; > + uint8_t old_cppr, backlog_prio, first_group, group_level; > uint8_t pipr_min, lsmfb_min, ring_min; > bool group_enabled; > uint32_t nvp_blk, nvp_idx; > @@ -961,10 +961,12 @@ static void xive2_tctx_set_cppr(XiveTCTX *tctx, uint8_t ring, uint8_t cppr) > * Recompute the PIPR based on local pending interrupts. It will > * be adjusted below if needed in case of pending group interrupts. > */ > +again: > pipr_min = xive_ipb_to_pipr(regs[TM_IPB]); > group_enabled = !!regs[TM_LGS]; > - lsmfb_min = (group_enabled) ? regs[TM_LSMFB] : 0xff; > + lsmfb_min = group_enabled ? regs[TM_LSMFB] : 0xff; > ring_min = ring; > + group_level = 0; > > /* PHYS updates also depend on POOL values */ > if (ring == TM_QW3_HV_PHYS) { > @@ -998,9 +1000,6 @@ static void xive2_tctx_set_cppr(XiveTCTX *tctx, uint8_t ring, uint8_t cppr) > } > } > > - /* PIPR should not be set to a value greater than CPPR */ > - regs[TM_PIPR] = (pipr_min > cppr) ? cppr : pipr_min; > - > rc = xive2_tctx_get_nvp_indexes(tctx, ring_min, &nvp_blk, &nvp_idx); > if (rc) { > qemu_log_mask(LOG_GUEST_ERROR, "XIVE: set CPPR on invalid context\n"); > @@ -1019,7 +1018,7 @@ static void xive2_tctx_set_cppr(XiveTCTX *tctx, uint8_t ring, uint8_t cppr) > > if (group_enabled && > lsmfb_min < cppr && > - lsmfb_min < regs[TM_PIPR]) { > + lsmfb_min < pipr_min) { > /* > * Thread has seen a group interrupt with a higher priority > * than the new cppr or pending local interrupt. Check the > @@ -1048,12 +1047,25 @@ static void xive2_tctx_set_cppr(XiveTCTX *tctx, uint8_t ring, uint8_t cppr) > nvp_blk, nvp_idx, > first_group, &group_level); > tctx->regs[ring_min + TM_LSMFB] = backlog_prio; > - if (backlog_prio != 0xFF) { > - xive2_presenter_backlog_decr(tctx->xptr, nvp_blk, nvp_idx, > - backlog_prio, group_level); > - regs[TM_PIPR] = backlog_prio; > + if (backlog_prio != lsmfb_min) { > + /* > + * If the group backlog scan finds a less favored or no interrupt, > + * then re-do the processing which may turn up a more favored > + * interrupt from IPB or the other pool. Backlog should not > + * find a priority < LSMFB. > + */ > + g_assert(backlog_prio >= lsmfb_min); > + goto again; > } > + > + xive2_presenter_backlog_decr(tctx->xptr, nvp_blk, nvp_idx, > + backlog_prio, group_level); > + pipr_min = backlog_prio; > } > + > + /* PIPR should not be set to a value greater than CPPR */ > + regs[TM_PIPR] = (pipr_min > cppr) ? cppr : pipr_min; > + > /* CPPR has changed, check if we need to raise a pending exception */ > xive_tctx_notify(tctx, ring_min, group_level); > }