Author: sbruno
Date: Wed Jan 25 14:37:05 2017
New Revision: 312755
URL: https://svnweb.freebsd.org/changeset/base/312755
Log:
Add error checking to the pci_find_cap(, PCIY_MSIX,) call that is returns
success and a good value. Only then try to use it and set the MSIX_ENABLE
bit.
With the current em(4) driver we have observed failures in this case in a
specific environment when pci_find_cap() would not return the assumed
value, which meant we ended up writing to PCI register 2 (PCI_DEVICE_ID)
which is read-only.
PR: 216456
Submitted by: bz
Modified:
head/sys/net/iflib.c
Modified: head/sys/net/iflib.c
==============================================================================
--- head/sys/net/iflib.c Wed Jan 25 13:42:38 2017 (r312754)
+++ head/sys/net/iflib.c Wed Jan 25 14:37:05 2017 (r312755)
@@ -3733,6 +3733,10 @@ iflib_device_register(device_t dev, void
if (sctx->isc_flags & IFLIB_SKIP_MSIX) {
msix = scctx->isc_vectors;
} else if (scctx->isc_msix_bar != 0)
+ /*
+ * The simple fact that isc_msix_bar is not 0 does not mean we
+ * we have a good value there that is known to work.
+ */
msix = iflib_msix_init(ctx);
else {
scctx->isc_vectors = 1;
@@ -4779,15 +4783,20 @@ iflib_msix_init(if_ctx_t ctx)
uint16_t pci_cmd_word;
int msix_ctrl, rid;
- rid = 0;
pci_cmd_word = pci_read_config(dev, PCIR_COMMAND, 2);
pci_cmd_word |= PCIM_CMD_BUSMASTEREN;
pci_write_config(dev, PCIR_COMMAND, pci_cmd_word, 2);
- 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);
+ rid = 0;
+ if (pci_find_cap(dev, PCIY_MSIX, &rid) == 0 && rid != 0) {
+ 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);
+ } else {
+ device_printf(dev, "PCIY_MSIX capability not found; "
+ "or rid %d == 0.\n", rid);
+ goto msi;
+ }
}
/*
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