[PATCH 07/23] pci, dmar: Update dmar units devices list during hotplug

Yinghai Lu
2012-03-06T07:19:15Z

When do pci remove/rescan on system that have more iommus, got

[ 894.089745] Set context mapping for c4:00.0
[ 894.110890] mpt2sas3: Allocated physical memory: size(4293 kB)
[ 894.112556] mpt2sas3: Current Controller Queue Depth(1883), Max Controller Queue Depth(2144)
[ 894.127278] mpt2sas3: Scatter Gather Elements per IO(128)
[ 894.361295] DRHD: handling fault status reg 2
[ 894.364053] DMAR:[DMA Read] Request device [c4:00.0] fault addr fffbe000
[ 894.364056] DMAR:[fault reason 02] Present bit in context entry is cl

it turns out when remove/rescan, pci dev will be freed and will get another new dev.
but drhd units still keep old one... so dmar_find_matched_drhd_unit will
return wrong drhd and iommu for the device that is not on first iommu.

So need to update devices in drhd_units during pci remove/rescan.

Could save domain/bus/device/function aside in the list and according that info
restore new dev to drhd_units later.
Then dmar_find_matched_drdh_unit and device_to_iommu could return right drhd and iommu.

Add remove_dev_from_drhd/restore_dev_to_drhd functions to do the real work.
call them in device ADD_DEVICE and UNBOUND_DRIVER

Need to do the samething to atsr. (expose dmar_atsr_units and add atsru->segment)

After patch, will right iommu for the new dev and will not get DMAR error any more.

-v2: add pci_dev_put/pci_dev_get to make refcount consistent.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Vinod Koul <vinod.koul@intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: iommu@lists.linux-foundation.org
---
drivers/iommu/intel-iommu.c | 187 ++++++++++++++++++++++++++++++++++++++++---
include/linux/dmar.h | 4 +
2 files changed, 181 insertions(+), 10 deletions(-)

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index c9c6053..39ef2ce 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -665,6 +665,159 @@ static struct intel_iommu *device_to_iommu(int segment, u8 bus, u8 devfn)
return NULL;
}

+#ifdef CONFIG_HOTPLUG
+struct dev_dmaru {
+ struct list_head list;
+ void *dmaru;
+ int index;
+ int segment;
+ unsigned char bus;
+ unsigned int devfn;
+};
+
+static int
+save_dev_dmaru(int segment, unsigned char bus, unsigned int devfn,
+ void *dmaru, int index, struct list_head *lh)
+{
+ struct dev_dmaru *m;
+
+ m = kzalloc(sizeof(*m), GFP_KERNEL);
+ if (!m)
+ return -ENOMEM;
+
+ m->segment = segment;
+ m->bus = bus;
+ m->devfn = devfn;
+ m->dmaru = dmaru;
+ m->index = index;
+
+ list_add(&m->list, lh);
+
+ return 0;
+}
+
+static void
+*get_dev_dmaru(int segment, unsigned char bus, unsigned int devfn,
+ int *index, struct list_head *lh)
+{
+ struct dev_dmaru *m;
+ void *dmaru = NULL;
+
+ list_for_each_entry(m, lh, list) {
+ if (m->segment == segment &&
+ m->bus == bus && m->devfn == devfn) {
+ *index = m->index;
+ dmaru = m->dmaru;
+ list_del(&m->list);
+ kfree(m);
+ break;
+ }
+ }
+
+ return dmaru;
+}
+
+static LIST_HEAD(saved_dev_drhd_list);
+
+static void remove_dev_from_drhd(struct pci_dev *dev)
+{
+ struct dmar_drhd_unit *drhd = NULL;
+ int segment = pci_domain_nr(dev->bus);
+ int i;
+
+ for_each_drhd_unit(drhd) {
+ if (drhd->ignored)
+ continue;
+ if (segment != drhd->segment)
+ continue;
+
+ for (i = 0; i < drhd->devices_cnt; i++) {
+ if (drhd->devices[i] == dev) {
+ /* save it at first if it is in drhd */
+ save_dev_dmaru(segment, dev->bus->number,
+ dev->devfn, drhd, i,
+ &saved_dev_drhd_list);
+ /* always remove it */
+ pci_dev_put(dev);
+ drhd->devices[i] = NULL;
+ return;
+ }
+ }
+ }
+}
+
+static void restore_dev_to_drhd(struct pci_dev *dev)
+{
+ struct dmar_drhd_unit *drhd = NULL;
+ int i;
+
+ /* find the stored drhd */
+ drhd = get_dev_dmaru(pci_domain_nr(dev->bus), dev->bus->number,
+ dev->devfn, &i, &saved_dev_drhd_list);
+ /* restore that into drhd */
+ if (drhd)
+ drhd->devices[i] = pci_dev_get(dev);
+}
+#else
+static void remove_dev_from_drhd(struct pci_dev *dev)
+{
+}
+
+static void restore_dev_to_drhd(struct pci_dev *dev)
+{
+}
+#endif
+
+#if defined(CONFIG_DMAR) && defined(CONFIG_HOTPLUG)
+static LIST_HEAD(saved_dev_atsr_list);
+
+static void remove_dev_from_atsr(struct pci_dev *dev)
+{
+ struct dmar_atsr_unit *atsr = NULL;
+ int segment = pci_domain_nr(dev->bus);
+ int i;
+
+ for_each_atsr_unit(atsr) {
+ if (segment != atsr->segment)
+ continue;
+
+ for (i = 0; i < atsr->devices_cnt; i++) {
+ if (atsr->devices[i] == dev) {
+ /* save it at first if it is in drhd */
+ save_dev_dmaru(segment, dev->bus->number,
+ dev->devfn, atsr, i,
+ &saved_dev_atsr_list);
+ /* always remove it */
+ pci_dev_put(dev);
+ atsr->devices[i] = NULL;
+ return;
+ }
+ }
+ }
+}
+
+static void restore_dev_to_atsr(struct pci_dev *dev)
+{
+ struct dmar_atsr_unit *atsr = NULL;
+ int i;
+
+ /* find the stored atsr */
+ atsr = get_dev_dmaru(pci_domain_nr(dev->bus), dev->bus->number,
+ dev->devfn, &i, &saved_dev_atsr_list);
+ /* restore that into atsr */
+ if (atsr)
+ atsr->devices[i] = pci_dev_get(dev);
+}
+#else
+static void remove_dev_from_atsr(struct pci_dev *dev)
+{
+}
+
+static void restore_dev_to_atsr(struct pci_dev *dev)
+{
+}
+#endif
+
static void domain_flush_cache(struct dmar_domain *domain,
void *addr, int size)
{
@@ -3474,6 +3627,7 @@ int __init dmar_parse_one_atsr(struct acpi_dmar_header *hdr)

atsru->hdr = hdr;
atsru->include_all = atsr->flags & 0x1;
+ atsru->segment = atsr->segment;

list_add(&atsru->list, &dmar_atsr_units);

@@ -3505,16 +3659,13 @@ 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;

dev = pci_physfn(dev);

- list_for_each_entry(atsru, &dmar_atsr_units, list) {
- atsr = container_of(atsru->hdr, struct acpi_dmar_atsr, header);
- if (atsr->segment == pci_domain_nr(dev->bus))
+ list_for_each_entry(atsru, &dmar_atsr_units, list)
+ if (atsru->segment == pci_domain_nr(dev->bus))
goto found;
- }

return 0;

@@ -3574,20 +3725,36 @@ static int device_notifier(struct notifier_block *nb,
struct pci_dev *pdev = to_pci_dev(dev);
struct dmar_domain *domain;

- if (iommu_no_mapping(dev))
+ if (unlikely(dev->bus != &pci_bus_type))
return 0;

- domain = find_domain(pdev);
- if (!domain)
- return 0;
+ switch (action) {
+ case BUS_NOTIFY_UNBOUND_DRIVER:
+ if (iommu_no_mapping(dev))
+ goto out;
+
+ if (iommu_pass_through)
+ goto out;
+
+ domain = find_domain(pdev);
+ if (!domain)
+ goto out;

- if (action == BUS_NOTIFY_UNBOUND_DRIVER && !iommu_pass_through) {
domain_remove_one_dev_info(domain, pdev);

if (!(domain->flags & DOMAIN_FLAG_VIRTUAL_MACHINE) &&
!(domain->flags & DOMAIN_FLAG_STATIC_IDENTITY) &&
list_empty(&domain->devices))
domain_exit(domain);
+out:
+ remove_dev_from_drhd(pdev);
+ remove_dev_from_atsr(pdev);
+
+ break;
+ case BUS_NOTIFY_ADD_DEVICE:
+ restore_dev_to_drhd(pdev);
+ restore_dev_to_atsr(pdev);
+ break;
}

return 0;
diff --git a/include/linux/dmar.h b/include/linux/dmar.h
index 731a609..57e1375 100644
--- a/include/linux/dmar.h
+++ b/include/linux/dmar.h
@@ -236,9 +236,13 @@ struct dmar_atsr_unit {
struct acpi_dmar_header *hdr; /* ACPI header */
struct pci_dev **devices; /* target devices */
int devices_cnt; /* target device count */
+ u16 segment; /* PCI domain */
u8 include_all:1; /* include all ports */
};

+#define for_each_atsr_unit(atsr) \
+ list_for_each_entry(atsr, &dmar_atsr_units, 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);
--
1.7.7