From 45fdc3ed87649d9f4d263a3745a57f29de340667 Mon Sep 17 00:00:00 2001 From: Anatoly Burakov Date: Mon, 30 Jul 2018 11:59:06 +0100 Subject: [PATCH] vfio: revert retry logic for MSI-X BAR mapping This reverts commit d4774a568ba0a5923229974a002972c83eb04570. The patch is incomplete because kernel 4.16+, while being capable of mapping MSI-X BARs, will also report if such a capability is available. Without checking this capability, gratuitous errors are displayed on kernels <4.16 while VFIO is attempting to mmap MSI-X BAR and fails, which can be confusing to the user. Fixes: d4774a568ba0 ("vfio: fix workaround of BAR mapping") Signed-off-by: Anatoly Burakov Acked-by: Jerin Jacob --- drivers/bus/pci/linux/pci_vfio.c | 93 ++++++++++++++------------------ 1 file changed, 41 insertions(+), 52 deletions(-) diff --git a/drivers/bus/pci/linux/pci_vfio.c b/drivers/bus/pci/linux/pci_vfio.c index bb6ef7b67a..686386d6a3 100644 --- a/drivers/bus/pci/linux/pci_vfio.c +++ b/drivers/bus/pci/linux/pci_vfio.c @@ -332,59 +332,50 @@ pci_vfio_mmap_bar(int vfio_dev_fd, struct mapped_pci_resource *vfio_res, void *bar_addr; struct pci_msix_table *msix_table = &vfio_res->msix_table; struct pci_map *bar = &vfio_res->maps[bar_index]; - bool again = false; if (bar->size == 0) /* Skip this BAR */ return 0; + if (msix_table->bar_index == bar_index) { + /* + * VFIO will not let us map the MSI-X table, + * but we can map around it. + */ + uint32_t table_start = msix_table->offset; + uint32_t table_end = table_start + msix_table->size; + table_end = (table_end + ~PAGE_MASK) & PAGE_MASK; + table_start &= PAGE_MASK; + + if (table_start == 0 && table_end >= bar->size) { + /* Cannot map this BAR */ + RTE_LOG(DEBUG, EAL, "Skipping BAR%d\n", bar_index); + bar->size = 0; + bar->addr = 0; + return 0; + } + + memreg[0].offset = bar->offset; + memreg[0].size = table_start; + memreg[1].offset = bar->offset + table_end; + memreg[1].size = bar->size - table_end; + + RTE_LOG(DEBUG, EAL, + "Trying to map BAR%d that contains the MSI-X " + "table. Trying offsets: " + "0x%04lx:0x%04lx, 0x%04lx:0x%04lx\n", bar_index, + memreg[0].offset, memreg[0].size, + memreg[1].offset, memreg[1].size); + } else { + memreg[0].offset = bar->offset; + memreg[0].size = bar->size; + } + /* reserve the address using an inaccessible mapping */ bar_addr = mmap(bar->addr, bar->size, 0, MAP_PRIVATE | MAP_ANONYMOUS | additional_flags, -1, 0); - if (bar_addr == MAP_FAILED) { - RTE_LOG(ERR, EAL, - "Failed to create inaccessible mapping for BAR%d\n", - bar_index); - return -1; - } - - memreg[0].offset = bar->offset; - memreg[0].size = bar->size; - do { + if (bar_addr != MAP_FAILED) { void *map_addr = NULL; - if (again) { - /* - * VFIO did not let us map the MSI-X table, - * but we can map around it. - */ - uint32_t table_start = msix_table->offset; - uint32_t table_end = table_start + msix_table->size; - table_end = (table_end + ~PAGE_MASK) & PAGE_MASK; - table_start &= PAGE_MASK; - - if (table_start == 0 && table_end >= bar->size) { - /* Cannot map this BAR */ - RTE_LOG(DEBUG, EAL, "Skipping BAR%d\n", - bar_index); - munmap(bar_addr, bar->size); - bar->size = 0; - bar->addr = 0; - return 0; - } - - memreg[0].offset = bar->offset; - memreg[0].size = table_start; - memreg[1].offset = bar->offset + table_end; - memreg[1].size = bar->size - table_end; - - RTE_LOG(DEBUG, EAL, - "Trying to map BAR%d that contains the MSI-X " - "table. Trying offsets: " - "0x%04lx:0x%04lx, 0x%04lx:0x%04lx\n", bar_index, - memreg[0].offset, memreg[0].size, - memreg[1].offset, memreg[1].size); - } - if (memreg[0].size) { /* actual map of first part */ map_addr = pci_map_resource(bar_addr, vfio_dev_fd, @@ -393,12 +384,6 @@ pci_vfio_mmap_bar(int vfio_dev_fd, struct mapped_pci_resource *vfio_res, MAP_FIXED); } - if (map_addr == MAP_FAILED && - msix_table->bar_index == bar_index && !again) { - again = true; - continue; - } - /* if there's a second part, try to map it */ if (map_addr != MAP_FAILED && memreg[1].offset && memreg[1].size) { @@ -419,8 +404,12 @@ pci_vfio_mmap_bar(int vfio_dev_fd, struct mapped_pci_resource *vfio_res, bar_index); return -1; } - break; - } while (again); + } else { + RTE_LOG(ERR, EAL, + "Failed to create inaccessible mapping for BAR%d\n", + bar_index); + return -1; + } bar->addr = bar_addr; return 0;