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From: Anatoly Burakov <anatoly.burakov@intel.com>
To: dev@dpdk.org
Cc: thomas@monjalon.net, jerin.jacob@caviumnetworks.com,
t.yoshimura8869@gmail.com
Date: Mon, 30 Jul 2018 11:59:06 +0100
Message-Id: <4107730371de4ac30367258cb3419df184d1ec16.1532947452.git.anatoly.burakov@intel.com>
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Subject: [dpdk-dev] [PATCH] vfio: revert retry logic for MSI-X BAR mapping
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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.
Signed-off-by: Anatoly Burakov <anatoly.burakov@intel.com>
---
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 bb6ef7b67..686386d6a 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;
--
2.17.1