Date: Wed, 25 Jan 2017 14:37:05 +0000 (UTC) From: Sean Bruno <sbruno@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r312755 - head/sys/net Message-ID: <201701251437.v0PEb5D7047773@repo.freebsd.org>
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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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