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vfio: revert retry logic for MSI-X BAR mapping

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This reverts commit d4774a568b.

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: d4774a568b ("vfio: fix workaround of BAR mapping")

Signed-off-by: Anatoly Burakov <anatoly.burakov@intel.com>
Acked-by: Jerin Jacob <jerin.jacob@caviumnetworks.com>
This commit is contained in:
Anatoly Burakov 2018-07-30 11:59:06 +01:00 committed by Thomas Monjalon
parent f771732be8
commit 45fdc3ed87
1 changed files with 41 additions and 52 deletions
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93
drivers/bus/pci/linux/pci_vfio.c
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@ -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;