No proof of concept is complete with only a single user, so here's an example for AMD IOMMU. This IOMMU is neatly associated with a device, so we don't need to leave the IOMMU device dangling in virtual space. This just has a couple fields from struct amd_iommu cherry picked to expose and looks something like this (pruned):
# find /sys | grep ivhd /sys/devices/pci0000:00/0000:00:00.2/iommu/ivhd0 /sys/devices/pci0000:00/0000:00:00.2/iommu/ivhd0/devices /sys/devices/pci0000:00/0000:00:00.2/iommu/ivhd0/devices/0000:00:00.0 /sys/devices/pci0000:00/0000:00:00.2/iommu/ivhd0/devices/0000:00:02.0 /sys/devices/pci0000:00/0000:00:00.2/iommu/ivhd0/devices/0000:00:04.0 /sys/devices/pci0000:00/0000:00:00.2/iommu/ivhd0/devices/0000:00:09.0 /sys/devices/pci0000:00/0000:00:00.2/iommu/ivhd0/devices/0000:00:11.0 /sys/devices/pci0000:00/0000:00:00.2/iommu/ivhd0/devices/0000:00:12.0 /sys/devices/pci0000:00/0000:00:00.2/iommu/ivhd0/devices/0000:00:12.2 /sys/devices/pci0000:00/0000:00:00.2/iommu/ivhd0/devices/0000:00:13.0 ... /sys/devices/pci0000:00/0000:00:00.2/iommu/ivhd0/power /sys/devices/pci0000:00/0000:00:00.2/iommu/ivhd0/power/control ... /sys/devices/pci0000:00/0000:00:00.2/iommu/ivhd0/device /sys/devices/pci0000:00/0000:00:00.2/iommu/ivhd0/subsystem /sys/devices/pci0000:00/0000:00:00.2/iommu/ivhd0/amd-iommu /sys/devices/pci0000:00/0000:00:00.2/iommu/ivhd0/amd-iommu/cap /sys/devices/pci0000:00/0000:00:00.2/iommu/ivhd0/amd-iommu/is_iommu_v2 /sys/devices/pci0000:00/0000:00:00.2/iommu/ivhd0/amd-iommu/features /sys/devices/pci0000:00/0000:00:00.2/iommu/ivhd0/uevent /sys/class/iommu/ivhd0 Signed-off-by: Alex Williamson <[email protected]> --- drivers/iommu/amd_iommu.c | 4 +++ drivers/iommu/amd_iommu_init.c | 53 ++++++++++++++++++++++++++++++++++++++++ 2 files changed, 57 insertions(+) diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c index 4621692..4849580 100644 --- a/drivers/iommu/amd_iommu.c +++ b/drivers/iommu/amd_iommu.c @@ -346,6 +346,8 @@ static int iommu_init_device(struct device *dev) dev->archdata.iommu = dev_data; + iommu_device_link(amd_iommu_rlookup_table[dev_data->devid], dev); + return 0; } @@ -370,6 +372,8 @@ static void iommu_uninit_device(struct device *dev) if (!dev_data) return; + iommu_device_unlink(amd_iommu_rlookup_table[dev_data->devid], dev); + iommu_group_remove_device(dev); /* Unlink from alias, it may change if another device is re-plugged */ diff --git a/drivers/iommu/amd_iommu_init.c b/drivers/iommu/amd_iommu_init.c index b76c58d..68f7c08 100644 --- a/drivers/iommu/amd_iommu_init.c +++ b/drivers/iommu/amd_iommu_init.c @@ -26,6 +26,8 @@ #include <linux/msi.h> #include <linux/amd-iommu.h> #include <linux/export.h> +#include <linux/iommu.h> +#include <linux/device.h> #include <asm/pci-direct.h> #include <asm/iommu.h> #include <asm/gart.h> @@ -1197,11 +1199,55 @@ static void init_iommu_perf_ctr(struct amd_iommu *iommu) iommu->max_counters = (u8) ((val >> 7) & 0xf); } +static ssize_t amd_iommu_show_cap(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct amd_iommu *iommu = dev->platform_data; + return sprintf(buf, "%x\n", iommu->cap); +} +static DEVICE_ATTR(cap, S_IRUGO, amd_iommu_show_cap, NULL); + +static ssize_t amd_iommu_show_features(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct amd_iommu *iommu = dev->platform_data; + return sprintf(buf, "%llx\n", iommu->features); +} +static DEVICE_ATTR(features, S_IRUGO, amd_iommu_show_features, NULL); + +static ssize_t amd_iommu_show_v2(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct amd_iommu *iommu = dev->platform_data; + return sprintf(buf, "%c\n", iommu->is_iommu_v2 ? 'Y' : 'N'); +} +static DEVICE_ATTR(is_iommu_v2, S_IRUGO, amd_iommu_show_v2, NULL); + +static struct attribute *amd_iommu_attrs[] = { + &dev_attr_cap.attr, + &dev_attr_features.attr, + &dev_attr_is_iommu_v2.attr, + NULL, +}; + +static struct attribute_group amd_iommu_group = { + .name = "amd-iommu", + .attrs = amd_iommu_attrs, +}; + +const struct attribute_group *amd_iommu_groups[] = { + &amd_iommu_group, + NULL, +}; static int iommu_init_pci(struct amd_iommu *iommu) { int cap_ptr = iommu->cap_ptr; u32 range, misc, low, high; + char *name; iommu->dev = pci_get_bus_and_slot(PCI_BUS_NUM(iommu->devid), iommu->devid & 0xff); @@ -1297,6 +1343,13 @@ static int iommu_init_pci(struct amd_iommu *iommu) amd_iommu_erratum_746_workaround(iommu); + name = kasprintf(GFP_KERNEL, "ivhd%d", iommu->index); + if (name) { + iommu_register_device(&iommu->dev->dev, name, + amd_iommu_groups, iommu); + kfree(name); + } + return pci_enable_device(iommu->dev); } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
