Initially (at boot) the device table values dumped are all of the active devices. Add a devid debugfs file to allow the user to select a single device table entry to dump (active or not). Let any devid value greater than the maximum allowable PCI ID (0xFFFF) restore the behavior to that effective at boot.
Signed-off-by: Gary R Hook <gary.h...@amd.com> --- drivers/iommu/amd_iommu_debugfs.c | 109 ++++++++++++++++++++++++++++++++++--- 1 file changed, 100 insertions(+), 9 deletions(-) diff --git a/drivers/iommu/amd_iommu_debugfs.c b/drivers/iommu/amd_iommu_debugfs.c index c4e071f7a5b9..aa6935340163 100644 --- a/drivers/iommu/amd_iommu_debugfs.c +++ b/drivers/iommu/amd_iommu_debugfs.c @@ -28,6 +28,7 @@ static DEFINE_RWLOCK(iommu_debugfs_lock); #define MAX_NAME_LEN 20 static unsigned int amd_iommu_verbose = 0; +static unsigned int amd_iommu_devid = ~0; static unsigned int amd_iommu_count_valid_dtes(int start, int end) { @@ -81,6 +82,76 @@ static const struct file_operations amd_iommu_debugfs_dtecount_ops = { .write = NULL, }; +static ssize_t amd_iommu_debugfs_devid_read(struct file *filp, + char __user *ubuf, + size_t count, loff_t *offp) +{ + struct amd_iommu *iommu = filp->private_data; + unsigned int obuflen = 512; + unsigned int oboff = 0; + ssize_t ret; + char *obuf; + + if (!iommu) + return 0; + + obuf = kmalloc(OBUFLEN, GFP_KERNEL); + if (!obuf) + return -ENOMEM; + + if (amd_iommu_verbose) + oboff += OSCNPRINTF("%02x:%02x:%x (%u / %04x)\n", + PCI_BUS_NUM(amd_iommu_devid), + PCI_SLOT(amd_iommu_devid), + PCI_FUNC(amd_iommu_devid), + amd_iommu_devid, amd_iommu_devid); + else + oboff += OSCNPRINTF("%u\n", amd_iommu_devid); + + ret = simple_read_from_buffer(ubuf, count, offp, obuf, oboff); + kfree(obuf); + + return ret; +} + +static ssize_t amd_iommu_debugfs_devid_write(struct file *filp, + const char __user *ubuf, + size_t count, loff_t *offp) +{ + unsigned int pci_id, pci_slot, pci_func; + unsigned int obuflen = 80; + ssize_t ret; + char *obuf; + int n; + + obuf = kmalloc(OBUFLEN, GFP_KERNEL); + if (!obuf) + return -ENOMEM; + + ret = simple_write_to_buffer(obuf, OBUFLEN, offp, ubuf, count); + + if (strnchr(obuf, OBUFLEN, ':')) + { + n = sscanf(obuf, "%x:%x.%x", &pci_id, &pci_slot, &pci_func); + if (n == 3) + amd_iommu_devid = PCI_DEVID(pci_id, PCI_DEVFN(pci_slot, pci_func)); + } else if (obuf[0] == '0' && obuf[1] == 'x') { + n = sscanf(obuf, "%x", &amd_iommu_devid); + } else { + n = sscanf(obuf, "%d", &amd_iommu_devid); + } + kfree(obuf); + + return ret; +} + +static const struct file_operations amd_iommu_debugfs_devid_ops = { + .owner = THIS_MODULE, + .open = simple_open, + .read = amd_iommu_debugfs_devid_read, + .write = amd_iommu_debugfs_devid_write, +}; + #define MAX_PCI_ID 0xFFFF #define PRINTDTE(i) OSCNPRINTF("%02x:%02x:%x - %016llx %016llx %016llx %016llx\n", \ @@ -106,19 +177,28 @@ static ssize_t amd_iommu_debugfs_dte_read(struct file *filp, return 0; /* Count the number of valid entries in the device table */ - istart = 0; - iend = MAX_PCI_ID; - n = amd_iommu_count_valid_dtes(istart, iend); + if (amd_iommu_devid > MAX_PCI_ID) { + istart = 0; + iend = MAX_PCI_ID; + n = amd_iommu_count_valid_dtes(istart, iend); + } else { + n = 1; + } obuflen = n * 80; obuf = kmalloc(OBUFLEN, GFP_KERNEL); if (!obuf) return -ENOMEM; - for (i = istart ; i <= iend ; i++) - if ((amd_iommu_dev_table[i].data[0] ^ 0x3) - || amd_iommu_dev_table[i].data[1]) - oboff += PRINTDTE(i); + if (amd_iommu_devid > MAX_PCI_ID) { + for (i = istart ; i <= iend ; i++) + if ((amd_iommu_dev_table[i].data[0] ^ 0x3) + || amd_iommu_dev_table[i].data[1]) + oboff += PRINTDTE(i); + } else { + i = amd_iommu_devid; + oboff += PRINTDTE(i); + } ret = simple_read_from_buffer(ubuf, count, offp, obuf, oboff); kfree(obuf); @@ -135,12 +215,17 @@ static const struct file_operations amd_iommu_debugfs_dte_ops = { static char readmetext[] = "devicetable Print active entries in the device table\n" +"devid Controls which device IDs are printed\n" "count Count of active devices\n" "verbose Provide additional descriptive text\n" "\n" " Dumping the Device Table\n" -"The device table is scanned for entries that appear to be active. The\n" -"default range is from 0 to 0xFFFF, and only active entries will be reported\n" +"The device table is scanned for entries that appear to be active.\n" +"The default (initial) range is from 0 to 0xFFFF, represented by a devid\n" +"value greater than 0xFFFF, and only active entries will be reported.\n" +"If devid is set to a specific value, only that device entry will be\n" +"displayed (active or not). devid may be specified as ##:##:#, a decimal\n" +"value, or a hex value.\n" "\n"; static ssize_t amd_iommu_debugfs_readme_read(struct file *filp, @@ -204,6 +289,12 @@ void amd_iommu_debugfs_setup(struct amd_iommu *iommu) if (!d_dte) goto err; + d_dte = debugfs_create_file("devid", 0400, + iommu->debugfs_instance, iommu, + &amd_iommu_debugfs_devid_ops); + if (!d_dte) + goto err; + d_dte = debugfs_create_file("README", 0400, iommu->debugfs_instance, iommu, &amd_iommu_debugfs_readme_ops); _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu