From d6f934fd48803d9e58040e2cbab2feafe9bb9f01 Mon Sep 17 00:00:00 2001 From: Alexey Kardashevskiy Date: Wed, 27 Sep 2017 16:52:31 +1000 Subject: [PATCH] powerpc/powernv: Reserve a hole which appears after enabling IOV In order to make generic IOV code work, the physical function IOV BAR should start from offset of the first VF. Since M64 segments share PE number space across PHB, and some PEs may be in use at the time when IOV is enabled, the existing code shifts the IOV BAR to the index of the first PE/VF. This creates a hole in IOMEM space which can be potentially taken by some other device. This reserves a temporary hole on a parent and releases it when IOV is disabled; the temporary resources are stored in pci_dn to avoid kmalloc/free. Signed-off-by: Alexey Kardashevskiy Acked-by: Bjorn Helgaas Signed-off-by: Michael Ellerman --- arch/powerpc/include/asm/pci-bridge.h | 1 + arch/powerpc/platforms/powernv/pci-ioda.c | 24 ++++++++++++++++++++--- 2 files changed, 22 insertions(+), 3 deletions(-) diff --git a/arch/powerpc/include/asm/pci-bridge.h b/arch/powerpc/include/asm/pci-bridge.h index 0b8aa1fe2d5f..62ed83db04ae 100644 --- a/arch/powerpc/include/asm/pci-bridge.h +++ b/arch/powerpc/include/asm/pci-bridge.h @@ -218,6 +218,7 @@ struct pci_dn { #endif struct list_head child_list; struct list_head list; + struct resource holes[PCI_SRIOV_NUM_BARS]; }; /* Get the pointer to a device_node's pci_dn */ diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c index fb5cd7511189..7e87867984e7 100644 --- a/arch/powerpc/platforms/powernv/pci-ioda.c +++ b/arch/powerpc/platforms/powernv/pci-ioda.c @@ -1002,9 +1002,12 @@ static int pnv_pci_vf_resource_shift(struct pci_dev *dev, int offset) } /* - * After doing so, there would be a "hole" in the /proc/iomem when - * offset is a positive value. It looks like the device return some - * mmio back to the system, which actually no one could use it. + * Since M64 BAR shares segments among all possible 256 PEs, + * we have to shift the beginning of PF IOV BAR to make it start from + * the segment which belongs to the PE number assigned to the first VF. + * This creates a "hole" in the /proc/iomem which could be used for + * allocating other resources so we reserve this area below and + * release when IOV is released. */ for (i = 0; i < PCI_SRIOV_NUM_BARS; i++) { res = &dev->resource[i + PCI_IOV_RESOURCES]; @@ -1018,7 +1021,22 @@ static int pnv_pci_vf_resource_shift(struct pci_dev *dev, int offset) dev_info(&dev->dev, "VF BAR%d: %pR shifted to %pR (%sabling %d VFs shifted by %d)\n", i, &res2, res, (offset > 0) ? "En" : "Dis", num_vfs, offset); + + if (offset < 0) { + devm_release_resource(&dev->dev, &pdn->holes[i]); + memset(&pdn->holes[i], 0, sizeof(pdn->holes[i])); + } + pci_update_resource(dev, i + PCI_IOV_RESOURCES); + + if (offset > 0) { + pdn->holes[i].start = res2.start; + pdn->holes[i].end = res2.start + size * offset - 1; + pdn->holes[i].flags = IORESOURCE_BUS; + pdn->holes[i].name = "pnv_iov_reserved"; + devm_request_resource(&dev->dev, res->parent, + &pdn->holes[i]); + } } return 0; } -- GitLab