Re: [PATCH 1/1] IOMMU: Save pci device id instead of pci_dev*pointer for DMAR devices
From: Bjorn Helgaas
Date: Thu Nov 07 2013 - 13:07:32 EST
On Tue, Nov 05, 2013 at 04:24:58PM +0800, Yijing Wang wrote:
> Currently, DMAR driver save target pci devices pointers for drhd/rmrr/atsr
> in (pci_dev *) array. This is not safe, because pci devices maybe
> hot added or removed during system running. They will have new pci_dev *
> pointer. So if there have two IOMMUs or more in system, these devices
> will find a wrong drhd during DMA mapping. And DMAR faults will occur.
> This patch save pci device id insted of (pci_dev *) to fix this issue,
> Because DMAR table just provide pci device id under a specific IOMMU,
> so there is no reason to bind IOMMU with the (pci_dev *). Other, here
> use list to manage devices' id for IOMMU, we can easily use list helper
> to manage device id.
>
> after remove and rescan a pci device
> [ 611.857095] dmar: DRHD: handling fault status reg 2
> [ 611.857109] dmar: DMAR:[DMA Read] Request device [86:00.3] fault addr ffff7000
> [ 611.857109] DMAR:[fault reason 02] Present bit in context entry is clear
> [ 611.857524] dmar: DRHD: handling fault status reg 102
> [ 611.857534] dmar: DMAR:[DMA Read] Request device [86:00.3] fault addr ffff6000
> [ 611.857534] DMAR:[fault reason 02] Present bit in context entry is clear
> [ 611.857936] dmar: DRHD: handling fault status reg 202
> [ 611.857947] dmar: DMAR:[DMA Read] Request device [86:00.3] fault addr ffff5000
> [ 611.857947] DMAR:[fault reason 02] Present bit in context entry is clear
> [ 611.858351] dmar: DRHD: handling fault status reg 302
> [ 611.858362] dmar: DMAR:[DMA Read] Request device [86:00.3] fault addr ffff4000
> [ 611.858362] DMAR:[fault reason 02] Present bit in context entry is clear
> [ 611.860819] IPv6: ADDRCONF(NETDEV_UP): eth3: link is not ready
> [ 611.860983] dmar: DRHD: handling fault status reg 402
> [ 611.860995] dmar: INTR-REMAP: Request device [[86:00.3] fault index a4
> [ 611.860995] INTR-REMAP:[fault reason 34] Present field in the IRTE entry is clear
>
> Signed-off-by: Yijing Wang <wangyijing@xxxxxxxxxx>
> ---
> drivers/iommu/dmar.c | 93 +++++++++++++-------------
> drivers/iommu/intel-iommu.c | 155 ++++++++++++++++++++++++++++---------------
> include/linux/dmar.h | 20 ++++--
> 3 files changed, 159 insertions(+), 109 deletions(-)
>
> diff --git a/drivers/iommu/dmar.c b/drivers/iommu/dmar.c
> index 785675a..9aa65a3 100644
> --- a/drivers/iommu/dmar.c
> +++ b/drivers/iommu/dmar.c
> @@ -65,12 +65,13 @@ static void __init dmar_register_drhd_unit(struct dmar_drhd_unit *drhd)
> }
>
> static int __init dmar_parse_one_dev_scope(struct acpi_dmar_device_scope *scope,
> - struct pci_dev **dev, u16 segment)
> + u16 segment, struct list_head *head)
> {
> struct pci_bus *bus;
> struct pci_dev *pdev = NULL;
> struct acpi_dmar_pci_path *path;
> int count;
> + struct dmar_device *dmar_dev;
>
> bus = pci_find_bus(segment, scope->bus);
> path = (struct acpi_dmar_pci_path *)(scope + 1);
> @@ -100,7 +101,6 @@ static int __init dmar_parse_one_dev_scope(struct acpi_dmar_device_scope *scope,
> if (!pdev) {
> pr_warn("Device scope device [%04x:%02x:%02x.%02x] not found\n",
> segment, scope->bus, path->dev, path->fn);
> - *dev = NULL;
> return 0;
> }
> if ((scope->entry_type == ACPI_DMAR_SCOPE_TYPE_ENDPOINT && \
> @@ -111,54 +111,39 @@ static int __init dmar_parse_one_dev_scope(struct acpi_dmar_device_scope *scope,
> pci_name(pdev));
> return -EINVAL;
> }
> - *dev = pdev;
> +
> + dmar_dev = kzalloc(sizeof(struct dmar_device), GFP_KERNEL);
> + if (!dmar_dev) {
> + pci_dev_put(pdev);
> + return -ENOMEM;
> + }
> +
> + dmar_dev->segment = segment;
> + dmar_dev->bus = pdev->bus->number;
> + dmar_dev->devfn = pdev->devfn;
> + list_add_tail(&dmar_dev->list, head);
> +
> + pci_dev_put(pdev);
> return 0;
> }
>
> -int __init dmar_parse_dev_scope(void *start, void *end, int *cnt,
> - struct pci_dev ***devices, u16 segment)
> +int __init dmar_parse_dev_scope(void *start, void *end, u16 segment,
> + struct list_head *head)
> {
> struct acpi_dmar_device_scope *scope;
> - void * tmp = start;
> - int index;
> int ret;
>
> - *cnt = 0;
> - while (start < end) {
> - scope = start;
> - if (scope->entry_type == ACPI_DMAR_SCOPE_TYPE_ENDPOINT ||
> - scope->entry_type == ACPI_DMAR_SCOPE_TYPE_BRIDGE)
> - (*cnt)++;
> - else if (scope->entry_type != ACPI_DMAR_SCOPE_TYPE_IOAPIC &&
> - scope->entry_type != ACPI_DMAR_SCOPE_TYPE_HPET) {
> - pr_warn("Unsupported device scope\n");
> - }
> - start += scope->length;
> - }
> - if (*cnt == 0)
> - return 0;
> -
> - *devices = kcalloc(*cnt, sizeof(struct pci_dev *), GFP_KERNEL);
> - if (!*devices)
> - return -ENOMEM;
> -
> - start = tmp;
> - index = 0;
> while (start < end) {
> scope = start;
> if (scope->entry_type == ACPI_DMAR_SCOPE_TYPE_ENDPOINT ||
> scope->entry_type == ACPI_DMAR_SCOPE_TYPE_BRIDGE) {
> - ret = dmar_parse_one_dev_scope(scope,
> - &(*devices)[index], segment);
> - if (ret) {
> - kfree(*devices);
> + ret = dmar_parse_one_dev_scope(scope, segment, head);
> + if (ret)
> return ret;
> - }
> - index ++;
> }
> start += scope->length;
> }
> -
> +
> return 0;
> }
>
> @@ -183,6 +168,7 @@ dmar_parse_one_drhd(struct acpi_dmar_header *header)
> dmaru->reg_base_addr = drhd->address;
> dmaru->segment = drhd->segment;
> dmaru->include_all = drhd->flags & 0x1; /* BIT0: INCLUDE_ALL */
> + INIT_LIST_HEAD(&dmaru->head);
>
> ret = alloc_iommu(dmaru);
> if (ret) {
> @@ -193,6 +179,19 @@ dmar_parse_one_drhd(struct acpi_dmar_header *header)
> return 0;
> }
>
> +static void drhd_free(struct dmar_drhd_unit *dmaru)
> +{
> + struct dmar_device *dev, *tmp;
> +
> + list_for_each_entry_safe(dev, tmp, &dmaru->head,
> + list) {
> + list_del(&dev->list);
> + kfree(dev);
> + }
> +
> + kfree(dmaru);
> +}
> +
> static int __init dmar_parse_dev(struct dmar_drhd_unit *dmaru)
> {
> struct acpi_dmar_hardware_unit *drhd;
> @@ -205,11 +204,10 @@ static int __init dmar_parse_dev(struct dmar_drhd_unit *dmaru)
>
> ret = dmar_parse_dev_scope((void *)(drhd + 1),
> ((void *)drhd) + drhd->header.length,
> - &dmaru->devices_cnt, &dmaru->devices,
> - drhd->segment);
> + drhd->segment, &dmaru->head);
> if (ret) {
> list_del(&dmaru->list);
> - kfree(dmaru);
> + drhd_free(dmaru);
> }
> return ret;
> }
> @@ -378,16 +376,18 @@ parse_dmar_table(void)
> return ret;
> }
>
> -static int dmar_pci_device_match(struct pci_dev *devices[], int cnt,
> - struct pci_dev *dev)
> +static int dmar_pci_device_match(struct pci_dev *dev,
> + struct list_head *head)
> {
> - int index;
> + struct dmar_device *dmar_dev;
>
> while (dev) {
> - for (index = 0; index < cnt; index++)
> - if (dev == devices[index])
> - return 1;
> -
> + list_for_each_entry(dmar_dev, head, list)
> + if (dmar_dev->segment == pci_domain_nr(dev->bus)
> + && dmar_dev->bus == dev->bus->number
> + && dmar_dev->devfn == dev->devfn)
> + return 1;
> +
> /* Check our parent */
> dev = dev->bus->self;
You didn't change this, but it looks like this may have the same problem
we've been talking about here:
http://lkml.kernel.org/r/20131105232903.3790.8738.stgit@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Namely, if "dev" is a VF on a virtual bus, "dev->bus->self == NULL", so
we won't search for any of the bridges leading to the VF. I proposed a
pci_upstream_bridge() interface that could be used like this:
/* Check our parent */
dev = pci_upstream_bridge(dev);
> }
> @@ -412,8 +412,7 @@ dmar_find_matched_drhd_unit(struct pci_dev *dev)
> drhd->segment == pci_domain_nr(dev->bus))
> return dmaru;
>
> - if (dmar_pci_device_match(dmaru->devices,
> - dmaru->devices_cnt, dev))
> + if (dmar_pci_device_match(dev, &dmaru->head))
> return dmaru;
> }
>
> diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
> index 15e9b57..b33fe0e 100644
> --- a/drivers/iommu/intel-iommu.c
> +++ b/drivers/iommu/intel-iommu.c
> @@ -650,7 +650,8 @@ static void domain_update_iommu_cap(struct dmar_domain *domain)
> static struct intel_iommu *device_to_iommu(int segment, u8 bus, u8 devfn)
> {
> struct dmar_drhd_unit *drhd = NULL;
> - int i;
> + struct dmar_device *dmar_dev;
> + struct pci_dev *pdev;
>
> for_each_drhd_unit(drhd) {
> if (drhd->ignored)
> @@ -658,16 +659,22 @@ static struct intel_iommu *device_to_iommu(int segment, u8 bus, u8 devfn)
> if (segment != drhd->segment)
> continue;
>
> - for (i = 0; i < drhd->devices_cnt; i++) {
> - if (drhd->devices[i] &&
> - drhd->devices[i]->bus->number == bus &&
> - drhd->devices[i]->devfn == devfn)
> - return drhd->iommu;
> - if (drhd->devices[i] &&
> - drhd->devices[i]->subordinate &&
> - drhd->devices[i]->subordinate->number <= bus &&
> - drhd->devices[i]->subordinate->busn_res.end >= bus)
> - return drhd->iommu;
> + list_for_each_entry(dmar_dev, &drhd->head, list) {
> + if (dmar_dev->bus == bus &&
> + dmar_dev->devfn == devfn)
> + return drhd->iommu;
> +
> + pdev = pci_get_domain_bus_and_slot(dmar_dev->segment,
> + dmar_dev->bus, dmar_dev->devfn);
> + if (pdev->subordinate &&
> + pdev->subordinate->number <= bus &&
> + pdev->subordinate->busn_res.end >= bus) {
> + pci_dev_put(pdev);
> + return drhd->iommu;
I don't know the details of how device_to_iommu() is used, but this
style (acquire ref to pci_dev, match it to some other object, drop
pci_dev ref, return object) makes me nervous. How do we know the
caller isn't depending on pci_dev to remain attached to the object?
What happens if the pci_dev disappears when we do the pci_dev_put()
here?
> + }
> +
> + if (pdev)
> + pci_dev_put(pdev);
> }
>
> if (drhd->include_all)
> @@ -2331,18 +2338,20 @@ static int domain_add_dev_info(struct dmar_domain *domain,
> static bool device_has_rmrr(struct pci_dev *dev)
> {
> struct dmar_rmrr_unit *rmrr;
> - int i;
> + struct dmar_device *dmar_dev;
>
> for_each_rmrr_units(rmrr) {
> - for (i = 0; i < rmrr->devices_cnt; i++) {
> - /*
> - * Return TRUE if this RMRR contains the device that
> - * is passed in.
> - */
> - if (rmrr->devices[i] == dev)
> - return true;
> - }
> + list_for_each_entry(dmar_dev, &rmrr->head, list)
> + /*
> + * Return TRUE if this RMRR contains the device that
> + * is passed in.
> + */
> + if (dmar_dev->segment == pci_domain_nr(dev->bus) &&
> + dmar_dev->bus == dev->bus->number &&
> + dmar_dev->devfn == dev->devfn)
> + return true;
> }
> +
> return false;
> }
>
> @@ -2451,7 +2460,7 @@ static int __init init_dmars(void)
> struct dmar_rmrr_unit *rmrr;
> struct pci_dev *pdev;
> struct intel_iommu *iommu;
> - int i, ret;
> + int ret;
>
> /*
> * for each drhd
> @@ -2605,8 +2614,10 @@ static int __init init_dmars(void)
> */
> printk(KERN_INFO "IOMMU: Setting RMRR:\n");
> for_each_rmrr_units(rmrr) {
> - for (i = 0; i < rmrr->devices_cnt; i++) {
> - pdev = rmrr->devices[i];
> + struct dmar_device *dmar_dev;
> + list_for_each_entry(dmar_dev, &rmrr->head, list) {
> + pdev = pci_get_domain_bus_and_slot(dmar_dev->segment,
> + dmar_dev->bus, dmar_dev->devfn);
> /*
> * some BIOS lists non-exist devices in DMAR
> * table.
> @@ -2615,9 +2626,11 @@ static int __init init_dmars(void)
> continue;
> ret = iommu_prepare_rmrr_dev(rmrr, pdev);
> if (ret)
> - printk(KERN_ERR
> - "IOMMU: mapping reserved region failed\n");
> - }
> + printk(KERN_ERR
> + "IOMMU: mapping reserved region failed\n");
> +
> + pci_dev_put(pdev);
> + }
> }
>
> iommu_prepare_isa();
> @@ -3301,30 +3314,30 @@ DECLARE_PCI_FIXUP_ENABLE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_IOAT_SNB, quir
> static void __init init_no_remapping_devices(void)
> {
> struct dmar_drhd_unit *drhd;
> + struct dmar_device *dmar_dev;
> + struct pci_dev *pdev = NULL;
>
> - for_each_drhd_unit(drhd) {
> - if (!drhd->include_all) {
> - int i;
> - for (i = 0; i < drhd->devices_cnt; i++)
> - if (drhd->devices[i] != NULL)
> - break;
> + for_each_drhd_unit(drhd)
> + if (!drhd->include_all)
> /* ignore DMAR unit if no pci devices exist */
> - if (i == drhd->devices_cnt)
> + if (list_empty(&drhd->head))
> drhd->ignored = 1;
> - }
> - }
> -
> +
> for_each_drhd_unit(drhd) {
> - int i;
> if (drhd->ignored || drhd->include_all)
> continue;
>
> - for (i = 0; i < drhd->devices_cnt; i++)
> - if (drhd->devices[i] &&
> - !IS_GFX_DEVICE(drhd->devices[i]))
> + list_for_each_entry(dmar_dev, &drhd->head, list) {
> + pdev = pci_get_domain_bus_and_slot(dmar_dev->segment,
> + dmar_dev->bus, dmar_dev->devfn);
> + if (!IS_GFX_DEVICE(pdev)) {
> + pci_dev_put(pdev);
> break;
> + }
> + pci_dev_put(pdev);
> + }
>
> - if (i < drhd->devices_cnt)
> + if (!IS_GFX_DEVICE(pdev))
I think this is clearly wrong. You acquire a pdev reference, drop the
reference, then look at pdev again after dropping the reference. But
as soon as you do the pci_dev_put(), you have to assume pdev is no
longer valid.
> continue;
>
> /* This IOMMU has *only* gfx devices. Either bypass it or
> @@ -3333,10 +3346,15 @@ static void __init init_no_remapping_devices(void)
> intel_iommu_gfx_mapped = 1;
> } else {
> drhd->ignored = 1;
> - for (i = 0; i < drhd->devices_cnt; i++) {
> - if (!drhd->devices[i])
> + list_for_each_entry(dmar_dev, &drhd->head, list) {
> + pdev = pci_get_domain_bus_and_slot(
> + dmar_dev->segment,
> + dmar_dev->bus,
> + dmar_dev->devfn);
> + if (!pdev)
> continue;
> - drhd->devices[i]->dev.archdata.iommu = DUMMY_DEVICE_DOMAIN_INFO;
> + pdev->dev.archdata.iommu = DUMMY_DEVICE_DOMAIN_INFO;
> + pci_dev_put(pdev);
> }
> }
> }
> @@ -3501,11 +3519,25 @@ int __init dmar_parse_one_rmrr(struct acpi_dmar_header *header)
> rmrr = (struct acpi_dmar_reserved_memory *)header;
> rmrru->base_address = rmrr->base_address;
> rmrru->end_address = rmrr->end_address;
> + INIT_LIST_HEAD(&rmrru->head);
>
> dmar_register_rmrr_unit(rmrru);
> return 0;
> }
>
> +static void rmrr_free(struct dmar_rmrr_unit *rmrru)
> +{
> + struct dmar_device *dev, *tmp;
> +
> + list_for_each_entry_safe(dev, tmp, &rmrru->head,
> + list) {
> + list_del(&dev->list);
> + kfree(dev);
> + }
> +
> + kfree(rmrru);
> +}
> +
> static int __init
> rmrr_parse_dev(struct dmar_rmrr_unit *rmrru)
> {
> @@ -3515,11 +3547,11 @@ rmrr_parse_dev(struct dmar_rmrr_unit *rmrru)
> rmrr = (struct acpi_dmar_reserved_memory *) rmrru->hdr;
> ret = dmar_parse_dev_scope((void *)(rmrr + 1),
> ((void *)rmrr) + rmrr->header.length,
> - &rmrru->devices_cnt, &rmrru->devices, rmrr->segment);
> + rmrr->segment, &rmrru->head);
>
> - if (ret || (rmrru->devices_cnt == 0)) {
> + if (ret || list_empty(&rmrru->head)) {
> list_del(&rmrru->list);
> - kfree(rmrru);
> + rmrr_free(rmrru);
> }
> return ret;
> }
> @@ -3538,12 +3570,25 @@ int __init dmar_parse_one_atsr(struct acpi_dmar_header *hdr)
>
> atsru->hdr = hdr;
> atsru->include_all = atsr->flags & 0x1;
> + INIT_LIST_HEAD(&atsru->head);
>
> list_add(&atsru->list, &dmar_atsr_units);
>
> return 0;
> }
>
> +static void atsr_free(struct dmar_atsr_unit *atsr)
> +{
> + struct dmar_device *dev, *tmp;
> +
> + list_for_each_entry_safe(dev, tmp, &atsr->head, list) {
> + list_del(&dev->list);
> + kfree(dev);
> + }
> +
> + kfree(atsr);
> +}
> +
> static int __init atsr_parse_dev(struct dmar_atsr_unit *atsru)
> {
> int rc;
> @@ -3555,11 +3600,10 @@ static int __init atsr_parse_dev(struct dmar_atsr_unit *atsru)
> atsr = container_of(atsru->hdr, struct acpi_dmar_atsr, header);
> rc = dmar_parse_dev_scope((void *)(atsr + 1),
> (void *)atsr + atsr->header.length,
> - &atsru->devices_cnt, &atsru->devices,
> - atsr->segment);
> - if (rc || !atsru->devices_cnt) {
> + atsr->segment, &atsru->head);
> + if (rc || list_empty(&atsru->head)) {
> list_del(&atsru->list);
> - kfree(atsru);
> + atsr_free(atsru);
> }
>
> return rc;
> @@ -3567,7 +3611,6 @@ static int __init atsr_parse_dev(struct dmar_atsr_unit *atsru)
>
> int dmar_find_matched_atsr_unit(struct pci_dev *dev)
> {
> - int i;
> struct pci_bus *bus;
> struct acpi_dmar_atsr *atsr;
> struct dmar_atsr_unit *atsru;
> @@ -3584,6 +3627,7 @@ int dmar_find_matched_atsr_unit(struct pci_dev *dev)
>
> found:
> for (bus = dev->bus; bus; bus = bus->parent) {
> + struct dmar_device *dmar_dev;
> struct pci_dev *bridge = bus->self;
>
> if (!bridge || !pci_is_pcie(bridge) ||
> @@ -3591,8 +3635,11 @@ found:
> return 0;
>
> if (pci_pcie_type(bridge) == PCI_EXP_TYPE_ROOT_PORT) {
> - for (i = 0; i < atsru->devices_cnt; i++)
> - if (atsru->devices[i] == bridge)
> + list_for_each_entry(dmar_dev, &atsru->head, list)
> + if (dmar_dev->segment ==
> + pci_domain_nr(bridge->bus) &&
> + dmar_dev->bus == bridge->bus->number &&
> + dmar_dev->devfn == bridge->devfn)
> return 1;
> break;
> }
> diff --git a/include/linux/dmar.h b/include/linux/dmar.h
> index b029d1a..5317cb0 100644
> --- a/include/linux/dmar.h
> +++ b/include/linux/dmar.h
> @@ -32,6 +32,13 @@ struct acpi_dmar_header;
> #define DMAR_INTR_REMAP 0x1
> #define DMAR_X2APIC_OPT_OUT 0x2
>
> +struct dmar_device {
> + struct list_head list;
> + u8 segment;
I think this should be u16. I didn't chase down how you're using it,
but Table 8.3 in the Intel VT-d spec shows Segment Number in a DRHD
structure as 16 bits.
> + u8 bus;
> + u8 devfn;
> +};
> +
> struct intel_iommu;
> #ifdef CONFIG_DMAR_TABLE
> extern struct acpi_table_header *dmar_tbl;
> @@ -39,8 +46,7 @@ struct dmar_drhd_unit {
> struct list_head list; /* list of drhd units */
> struct acpi_dmar_header *hdr; /* ACPI header */
> u64 reg_base_addr; /* register base address*/
> - struct pci_dev **devices; /* target device array */
> - int devices_cnt; /* target device count */
> + struct list_head head; /* target devices' list */
s/devices'/device/ (also below). This is not a contraction or a
possessive construct, so no apostrophe is needed.
> u16 segment; /* PCI domain */
> u8 ignored:1; /* ignore drhd */
> u8 include_all:1;
> @@ -139,8 +145,7 @@ struct dmar_rmrr_unit {
> struct acpi_dmar_header *hdr; /* ACPI header */
> u64 base_address; /* reserved base address*/
> u64 end_address; /* reserved end address */
> - struct pci_dev **devices; /* target devices */
> - int devices_cnt; /* target device count */
> + struct list_head head; /* target devices' list */
> };
>
> #define for_each_rmrr_units(rmrr) \
> @@ -149,16 +154,15 @@ struct dmar_rmrr_unit {
> struct dmar_atsr_unit {
> struct list_head list; /* list of ATSR units */
> struct acpi_dmar_header *hdr; /* ACPI header */
> - struct pci_dev **devices; /* target devices */
> - int devices_cnt; /* target device count */
> u8 include_all:1; /* include all ports */
> + struct list_head head; /* target devices' list */
> };
>
> int dmar_parse_rmrr_atsr_dev(void);
> extern int dmar_parse_one_rmrr(struct acpi_dmar_header *header);
> extern int dmar_parse_one_atsr(struct acpi_dmar_header *header);
> -extern int dmar_parse_dev_scope(void *start, void *end, int *cnt,
> - struct pci_dev ***devices, u16 segment);
> +extern int dmar_parse_dev_scope(void *start, void *end, u16 segment,
> + struct list_head *head);
> extern int intel_iommu_init(void);
> #else /* !CONFIG_INTEL_IOMMU: */
> static inline int intel_iommu_init(void) { return -ENODEV; }
> --
> 1.7.1
>
>
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