From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:47756 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S2389884AbgKZPJE (ORCPT ); Thu, 26 Nov 2020 10:09:04 -0500 Received: from pps.filterd (m0098419.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 0AQF29Vx120197 for ; Thu, 26 Nov 2020 10:09:03 -0500 Received: from ppma05fra.de.ibm.com (6c.4a.5195.ip4.static.sl-reverse.com [149.81.74.108]) by mx0b-001b2d01.pphosted.com with ESMTP id 3526npp9qb-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT) for ; Thu, 26 Nov 2020 10:09:03 -0500 Received: from pps.filterd (ppma05fra.de.ibm.com [127.0.0.1]) by ppma05fra.de.ibm.com (8.16.0.42/8.16.0.42) with SMTP id 0AQF7SsL031597 for ; Thu, 26 Nov 2020 15:09:01 GMT Received: from b06cxnps4076.portsmouth.uk.ibm.com (d06relay13.portsmouth.uk.ibm.com [9.149.109.198]) by ppma05fra.de.ibm.com with ESMTP id 352ata03tw-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT) for ; Thu, 26 Nov 2020 15:09:01 +0000 Subject: Re: [PATCH v2] s390/pci: fix CPU address in MSI for directed IRQ References: <20201125142930.GA13435@oc3871087118.ibm.com> <31dfedbf-cfe4-09d2-5dc5-ee9fb847d109@linux.ibm.com> <8a072525-7915-27c8-40ef-d7c826419a89@linux.ibm.com> <10403770-249e-ccbc-a90a-f4ceeb190346@linux.ibm.com> <20201125155818.GA16580@oc3871087118.ibm.com> <20201126121934.GA514@oc3871087118.ibm.com> From: Niklas Schnelle Message-ID: <4143b73b-0dd1-3d07-3fe0-7362f4b46f17@linux.ibm.com> Date: Thu, 26 Nov 2020 16:08:57 +0100 MIME-Version: 1.0 In-Reply-To: <20201126121934.GA514@oc3871087118.ibm.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit List-ID: To: Alexander Gordeev Cc: Halil Pasic , linux-s390@vger.kernel.org On 11/26/20 1:19 PM, Alexander Gordeev wrote: > The directed MSIs are delivered to CPUs whose address is > written to the MSI message data. The current code assumes > that a CPU logical number (as it is seen by the kernel) > is also that CPU address. > > The above assumption is not correct, as the CPU address > is rather the value returned by STAP instruction. That > value is not necessarily matches the kernel logical CPU > number. I took the liberty of correcting the "is not" grammar error above to "does not necessarily match". > > Fixes: e979ce7bced2 ("s390/pci: provide support for CPU directed interrupts") > Signed-off-by: Alexander Gordeev Still works well and checkpatches clean. I > --- > arch/s390/pci/pci_irq.c | 15 ++++++++++++--- > 1 file changed, 12 insertions(+), 3 deletions(-) > > diff --git a/arch/s390/pci/pci_irq.c b/arch/s390/pci/pci_irq.c > index 743f257cf2cb..1309fd302f58 100644 > --- a/arch/s390/pci/pci_irq.c > +++ b/arch/s390/pci/pci_irq.c > @@ -103,9 +103,10 @@ static int zpci_set_irq_affinity(struct irq_data *data, const struct cpumask *de > { > struct msi_desc *entry = irq_get_msi_desc(data->irq); > struct msi_msg msg = entry->msg; > + int cpu_addr = smp_cpu_get_cpu_address(cpumask_first(dest)); > > msg.address_lo &= 0xff0000ff; > - msg.address_lo |= (cpumask_first(dest) << 8); > + msg.address_lo |= (cpu_addr << 8); > pci_write_msi_msg(data->irq, &msg); > > return IRQ_SET_MASK_OK; > @@ -238,6 +239,7 @@ int arch_setup_msi_irqs(struct pci_dev *pdev, int nvec, int type) > unsigned long bit; > struct msi_desc *msi; > struct msi_msg msg; > + int cpu_addr; > int rc, irq; > > zdev->aisb = -1UL; > @@ -287,9 +289,16 @@ int arch_setup_msi_irqs(struct pci_dev *pdev, int nvec, int type) > handle_percpu_irq); > msg.data = hwirq - bit; > if (irq_delivery == DIRECTED) { > + if (msi->affinity) { > + cpu = cpumask_first(&msi->affinity->mask); > + cpu_addr = smp_cpu_get_cpu_address(cpu); > + } else { > + cpu_addr = 0; > + } One question I haven't really figured out from looking at the spec is why using cpu_addr = 0; is a good fallback. Shouldn't that be smp_cpu_get_cpu_address(0) or do we now know that the CPU addresses always start at 0? > + > msg.address_lo = zdev->msi_addr & 0xff0000ff; > - msg.address_lo |= msi->affinity ? > - (cpumask_first(&msi->affinity->mask) << 8) : 0; > + msg.address_lo |= (cpu_addr << 8); > + > for_each_possible_cpu(cpu) { > airq_iv_set_data(zpci_ibv[cpu], hwirq, irq); > } >