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Date: Thu, 10 Dec 2020 17:34:08 +0100 From: Niklas Schnelle <schnelle@...ux.ibm.com> To: Greg Kroah-Hartman <gregkh@...uxfoundation.org>, linux-kernel@...r.kernel.org, Naresh Kamboju <naresh.kamboju@...aro.org> Cc: stable@...r.kernel.org, Alexander Gordeev <agordeev@...ux.ibm.com>, Halil Pasic <pasic@...ux.ibm.com>, Heiko Carstens <hca@...ux.ibm.com> Subject: Re: [PATCH 5.4 21/54] s390/pci: fix CPU address in MSI for directed IRQ Hi Greg, sorry to bother you but I missed that the smp_cpu_get_cpu_address() address used here was only added with the commit 42d211a1ae3b77 ("s390/cpuinfo: show processor physical address") which landed in v5.7-rc1. This would therefore break if ever called (luckily it would not be called on any shipped hardware) and also causes a missing declaration warning as reported by Naresh Kamboju thanks! Since this is as of now just a spec fix, as on all known hardware the Linux CPU Id always matches the CPU Address, I would recommend to simply revert the commit. Thanks in advance! Best regards, Niklas Schnelle On 12/10/20 3:26 PM, Greg Kroah-Hartman wrote: > From: Alexander Gordeev <agordeev@...ux.ibm.com> > > commit a2bd4097b3ec242f4de4924db463a9c94530e03a upstream. > > The directed MSIs are delivered to CPUs whose address is > written to the MSI message address. The current code assumes > that a CPU logical number (as it is seen by the kernel) > is also the CPU address. > > The above assumption is not correct, as the CPU address > is rather the value returned by STAP instruction. That > value does not necessarily match the kernel logical CPU > number. > > Fixes: e979ce7bced2 ("s390/pci: provide support for CPU directed interrupts") > Cc: <stable@...r.kernel.org> # v5.2+ > Signed-off-by: Alexander Gordeev <agordeev@...ux.ibm.com> > Reviewed-by: Halil Pasic <pasic@...ux.ibm.com> > Reviewed-by: Niklas Schnelle <schnelle@...ux.ibm.com> > Signed-off-by: Niklas Schnelle <schnelle@...ux.ibm.com> > Signed-off-by: Heiko Carstens <hca@...ux.ibm.com> > Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org> > > --- > arch/s390/pci/pci_irq.c | 14 +++++++++++--- > 1 file changed, 11 insertions(+), 3 deletions(-) > > --- 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 > { > 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 * > unsigned long bit; > struct msi_desc *msi; > struct msi_msg msg; > + int cpu_addr; > int rc, irq; > > zdev->aisb = -1UL; > @@ -287,9 +289,15 @@ int arch_setup_msi_irqs(struct pci_dev * > handle_percpu_irq); > msg.data = hwirq - bit; > if (irq_delivery == DIRECTED) { > + if (msi->affinity) > + cpu = cpumask_first(&msi->affinity->mask); > + else > + cpu = 0; > + cpu_addr = smp_cpu_get_cpu_address(cpu); > + > 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); > } > >
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