nvmet: pci-epf: do not fall back to using INTX if not supported

Some endpoint PCIe controllers do not support raising legacy INTX
interrupts. This support is indicated by the intx_capable field of
struct pci_epc_features. Modify nvmet_pci_epf_raise_irq() to not
automatically fallback to trying raising an INTX interrupt after an MSI
or MSI-X error if the controller does not support INTX.

Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>

diff --git a/drivers/nvme/target/pci-epf.c b/drivers/nvme/target/pci-epf.c
index d5442991f2fbd4f42d3a0dc734a0648a8c8fbbe0..bde7818c673d8c958785133110020f19c2577b5c 100644 (file)
--- a/drivers/nvme/target/pci-epf.c
+++ b/drivers/nvme/target/pci-epf.c
@@ -636,14 +636,16 @@ static void nvmet_pci_epf_raise_irq(struct nvmet_pci_epf_ctrl *ctrl,
        switch (nvme_epf->irq_type) {
        case PCI_IRQ_MSIX:
        case PCI_IRQ_MSI:
+               /*
+                * If we fail to raise an MSI or MSI-X interrupt, it is likely
+                * because the host is using legacy INTX IRQs (e.g. BIOS,
+                * grub), but we can fallback to the INTX type only if the
+                * endpoint controller supports this type.
+                */
                ret = pci_epc_raise_irq(epf->epc, epf->func_no, epf->vfunc_no,
                                        nvme_epf->irq_type, cq->vector + 1);
-               if (!ret)
+               if (!ret || !nvme_epf->epc_features->intx_capable)
                        break;
-               /*
-                * If we got an error, it is likely because the host is using
-                * legacy IRQs (e.g. BIOS, grub).
-                */
                fallthrough;
        case PCI_IRQ_INTX:
                ret = pci_epc_raise_irq(epf->epc, epf->func_no, epf->vfunc_no,