diff mbox series

[v2] vfio: fix workaround of BAR0 mapping

Message ID 20180712030833.4887-1-t.yoshimura8869@gmail.com (mailing list archive)
State Superseded, archived
Headers
Series [v2] vfio: fix workaround of BAR0 mapping |

Checks

Context Check Description
ci/checkpatch success coding style OK
ci/Intel-compilation success Compilation OK

Commit Message

Takeshi Yoshimura July 12, 2018, 3:08 a.m. UTC 
  The workaround of BAR0 mapping does not work if BAR0 area is smaller
than page size (64KB in ppc). In addition, we no longer need the
workaround in recent Linux because VFIO allows MSIX mapping (*).
This fix is just to skip the workaround if BAR0 is smarller than a page.

(*): "vfio-pci: Allow mapping MSIX BAR",
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/
commit/id=a32295c612c57990d17fb0f41e7134394b2f35f6

Fixes: 90a1633b2347 ("eal/linux: allow to map BARs with MSI-X tables")

Signed-off-by: Takeshi Yoshimura <t.yoshimura8869@gmail.com>
---

Fixed checkpatch warnings

 drivers/bus/pci/linux/pci_vfio.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

Comments

Anatoly Burakov July 12, 2018, 9:10 a.m. UTC | #1 
On 12-Jul-18 4:08 AM, Takeshi Yoshimura wrote:
> The workaround of BAR0 mapping does not work if BAR0 area is smaller
> than page size (64KB in ppc). In addition, we no longer need the
> workaround in recent Linux because VFIO allows MSIX mapping (*).
> This fix is just to skip the workaround if BAR0 is smarller than a page.
> 
> (*): "vfio-pci: Allow mapping MSIX BAR",
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/
> commit/id=a32295c612c57990d17fb0f41e7134394b2f35f6
> 
> Fixes: 90a1633b2347 ("eal/linux: allow to map BARs with MSI-X tables")
> 
> Signed-off-by: Takeshi Yoshimura <t.yoshimura8869@gmail.com>
> ---

Minimum support kernel version in DPDK is 3.2, we cannot rely on 
functionality provided by the recent kernel versions.

It would be better if you modified the check at line 350 instead (or 
added a new check, specifically testing for whether BAR size is less 
than page size).
diff mbox series

Patch

diff --git a/drivers/bus/pci/linux/pci_vfio.c b/drivers/bus/pci/linux/pci_vfio.c
index aeeaa9ed8..b8f4a11f4 100644
--- a/drivers/bus/pci/linux/pci_vfio.c
+++ b/drivers/bus/pci/linux/pci_vfio.c
@@ -337,7 +337,8 @@  pci_vfio_mmap_bar(int vfio_dev_fd, struct mapped_pci_resource *vfio_res,
 		/* Skip this BAR */
 		return 0;
 
-	if (msix_table->bar_index == bar_index) {
+	if (msix_table->bar_index == bar_index &&
+		bar->size > (uint64_t)PAGE_SIZE) {
 		/*
 		 * VFIO will not let us map the MSI-X table,
 		 * but we can map around it.