5.4-stable review patch. If anyone has any objections, please let me know.
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From: Gerd Bayer gbayer@linux.ibm.com
[ Upstream commit ab42fcb511fd9d241bbab7cc3ca04e34e9fc0666 ]
On a PCI adapter that provides up to 8 MSI interrupt sources the s390 implementation of PCI interrupts rejected to accommodate them, although the underlying hardware is able to support that.
For MSI-X it is sufficient to allocate a single irq_desc per msi_desc, but for MSI multiple irq descriptors are attached to and controlled by a single msi descriptor. Add the appropriate loops to maintain multiple irq descriptors and tie/untie them to/from the appropriate AIBV bit, if a device driver allocates more than 1 MSI interrupt.
Common PCI code passes on requests to allocate a number of interrupt vectors based on the device drivers' demand and the PCI functions' capabilities. However, the root-complex of s390 systems support just a limited number of interrupt vectors per PCI function. Produce a kernel log message to inform about any architecture-specific capping that might be done.
With this change, we had a PCI adapter successfully raising interrupts to its device driver via all 8 sources.
Fixes: a384c8924a8b ("s390/PCI: Fix single MSI only check") Signed-off-by: Gerd Bayer gbayer@linux.ibm.com Reviewed-by: Niklas Schnelle schnelle@linux.ibm.com Signed-off-by: Vasily Gorbik gor@linux.ibm.com Signed-off-by: Sasha Levin sashal@kernel.org --- arch/s390/pci/pci_irq.c | 62 ++++++++++++++++++++++++++++------------- 1 file changed, 42 insertions(+), 20 deletions(-)
diff --git a/arch/s390/pci/pci_irq.c b/arch/s390/pci/pci_irq.c index b36f5ef34a6c1..690f6999287bc 100644 --- a/arch/s390/pci/pci_irq.c +++ b/arch/s390/pci/pci_irq.c @@ -262,8 +262,8 @@ static int __alloc_airq(struct zpci_dev *zdev, int msi_vecs,
int arch_setup_msi_irqs(struct pci_dev *pdev, int nvec, int type) { + unsigned int hwirq, msi_vecs, irqs_per_msi, i, cpu; struct zpci_dev *zdev = to_zpci(pdev); - unsigned int hwirq, msi_vecs, cpu; struct msi_desc *msi; struct msi_msg msg; unsigned long bit; @@ -273,30 +273,46 @@ int arch_setup_msi_irqs(struct pci_dev *pdev, int nvec, int type) zdev->aisb = -1UL; zdev->msi_first_bit = -1U;
- if (type == PCI_CAP_ID_MSI && nvec > 1) - return 1; msi_vecs = min_t(unsigned int, nvec, zdev->max_msi); + if (msi_vecs < nvec) { + pr_info("%s requested %d irqs, allocate system limit of %d", + pci_name(pdev), nvec, zdev->max_msi); + }
rc = __alloc_airq(zdev, msi_vecs, &bit); if (rc < 0) return rc;
- /* Request MSI interrupts */ + /* + * Request MSI interrupts: + * When using MSI, nvec_used interrupt sources and their irq + * descriptors are controlled through one msi descriptor. + * Thus the outer loop over msi descriptors shall run only once, + * while two inner loops iterate over the interrupt vectors. + * When using MSI-X, each interrupt vector/irq descriptor + * is bound to exactly one msi descriptor (nvec_used is one). + * So the inner loops are executed once, while the outer iterates + * over the MSI-X descriptors. + */ hwirq = bit; msi_for_each_desc(msi, &pdev->dev, MSI_DESC_NOTASSOCIATED) { - rc = -EIO; if (hwirq - bit >= msi_vecs) break; - irq = __irq_alloc_descs(-1, 0, 1, 0, THIS_MODULE, - (irq_delivery == DIRECTED) ? - msi->affinity : NULL); + irqs_per_msi = min_t(unsigned int, msi_vecs, msi->nvec_used); + irq = __irq_alloc_descs(-1, 0, irqs_per_msi, 0, THIS_MODULE, + (irq_delivery == DIRECTED) ? + msi->affinity : NULL); if (irq < 0) return -ENOMEM; - rc = irq_set_msi_desc(irq, msi); - if (rc) - return rc; - irq_set_chip_and_handler(irq, &zpci_irq_chip, - handle_percpu_irq); + + for (i = 0; i < irqs_per_msi; i++) { + rc = irq_set_msi_desc_off(irq, i, msi); + if (rc) + return rc; + irq_set_chip_and_handler(irq + i, &zpci_irq_chip, + handle_percpu_irq); + } + msg.data = hwirq - bit; if (irq_delivery == DIRECTED) { if (msi->affinity) @@ -309,19 +325,22 @@ int arch_setup_msi_irqs(struct pci_dev *pdev, int nvec, int type) msg.address_lo |= (cpu_addr << 8);
for_each_possible_cpu(cpu) { - airq_iv_set_data(zpci_ibv[cpu], hwirq, irq); + for (i = 0; i < irqs_per_msi; i++) + airq_iv_set_data(zpci_ibv[cpu], + hwirq + i, irq + i); } } else { msg.address_lo = zdev->msi_addr & 0xffffffff; - airq_iv_set_data(zdev->aibv, hwirq, irq); + for (i = 0; i < irqs_per_msi; i++) + airq_iv_set_data(zdev->aibv, hwirq + i, irq + i); } msg.address_hi = zdev->msi_addr >> 32; pci_write_msi_msg(irq, &msg); - hwirq++; + hwirq += irqs_per_msi; }
zdev->msi_first_bit = bit; - zdev->msi_nr_irqs = msi_vecs; + zdev->msi_nr_irqs = hwirq - bit;
if (irq_delivery == DIRECTED) rc = zpci_set_directed_irq(zdev); @@ -330,13 +349,14 @@ int arch_setup_msi_irqs(struct pci_dev *pdev, int nvec, int type) if (rc) return rc;
- return (msi_vecs == nvec) ? 0 : msi_vecs; + return (zdev->msi_nr_irqs == nvec) ? 0 : zdev->msi_nr_irqs; }
void arch_teardown_msi_irqs(struct pci_dev *pdev) { struct zpci_dev *zdev = to_zpci(pdev); struct msi_desc *msi; + unsigned int i; int rc;
/* Disable interrupts */ @@ -349,8 +369,10 @@ void arch_teardown_msi_irqs(struct pci_dev *pdev)
/* Release MSI interrupts */ msi_for_each_desc(msi, &pdev->dev, MSI_DESC_ASSOCIATED) { - irq_set_msi_desc(msi->irq, NULL); - irq_free_desc(msi->irq); + for (i = 0; i < msi->nvec_used; i++) { + irq_set_msi_desc(msi->irq + i, NULL); + irq_free_desc(msi->irq + i); + } msi->msg.address_lo = 0; msi->msg.address_hi = 0; msi->msg.data = 0;