git: 453f85caa93a - stable/13 - ixv: Check cap return before MSI-X enable write

The branch stable/13 has been updated by kbowling:

URL: https://cgit.FreeBSD.org/src/commit/?id=453f85caa93a431911b66b2cd781595e4ebd59ec

commit 453f85caa93a431911b66b2cd781595e4ebd59ec
Author:     Jeremiah Lott <jlott@averesystems.com>
AuthorDate: 2024-10-27 07:18:54 +0000
Commit:     Kevin Bowling <kbowling@FreeBSD.org>
CommitDate: 2024-10-30 01:02:46 +0000

    ixv: Check cap return before MSI-X enable write
    
    In the QEMU workaround code in if_ixv.c, the ixv driver calls
    pci_find_cap(dev, PCIY_MSIX, &rid). It is not checking the return code
    from that function and the function appears to always be failing. This
    then causes the driver to use the rid variable uninitialized, which
    will mean setting a bit at an arbitrary offset in pci config space. For
    now, this seems to have no adverse impact, but it could easily cause
    very subtle problems.
    
    PR:             207037
    Sponsored by:   BBOX.io
    
    (cherry picked from commit b87b3696c973ef0a9df70143cd89f6b488531e93)
---
 sys/dev/ixgbe/if_ixv.c | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/sys/dev/ixgbe/if_ixv.c b/sys/dev/ixgbe/if_ixv.c
index 91ed47df429d..1a9514dc5b07 100644
--- a/sys/dev/ixgbe/if_ixv.c
+++ b/sys/dev/ixgbe/if_ixv.c
@@ -1073,11 +1073,14 @@ ixv_if_msix_intr_assign(if_ctx_t ctx, int msix)
 	 */
 	if (sc->hw.mac.type == ixgbe_mac_82599_vf) {
 		int msix_ctrl;
-		pci_find_cap(dev, PCIY_MSIX, &rid);
-		rid += PCIR_MSIX_CTRL;
-		msix_ctrl = pci_read_config(dev, rid, 2);
-		msix_ctrl |= PCIM_MSIXCTRL_MSIX_ENABLE;
-		pci_write_config(dev, rid, msix_ctrl, 2);
+		if (pci_find_cap(dev, PCIY_MSIX, &rid)) {
+			device_printf(dev, "Finding MSIX capability failed\n");
+		} else {
+			rid += PCIR_MSIX_CTRL;
+			msix_ctrl = pci_read_config(dev, rid, 2);
+			msix_ctrl |= PCIM_MSIXCTRL_MSIX_ENABLE;
+			pci_write_config(dev, rid, msix_ctrl, 2);
+		}
 	}
 
 	return (0);