Global DMA and interrupt remapping resources may be accessed in
interrupt context, so use RCU instead of rwsem to protect them
in such cases.
Signed-off-by: Jiang Liu <jiang.liu@xxxxxxxxxxxxxxx>
---
drivers/iommu/dmar.c | 33 ++++++++++++++++++++-------------
drivers/iommu/intel-iommu.c | 20 ++++++++++++++++----
include/linux/dmar.h | 23 +++++++++++++++++------
3 files changed, 53 insertions(+), 23 deletions(-)
diff --git a/drivers/iommu/dmar.c b/drivers/iommu/dmar.c
index c9aca88..6e4d851 100644
--- a/drivers/iommu/dmar.c
+++ b/drivers/iommu/dmar.c
@@ -71,13 +71,13 @@ static void __init dmar_register_drhd_unit(struct dmar_drhd_unit *drhd)
* the very end.
*/
if (drhd->include_all)
- list_add_tail(&drhd->list, &dmar_drhd_units);
+ list_add_tail_rcu(&drhd->list, &dmar_drhd_units);
else
- list_add(&drhd->list, &dmar_drhd_units);
+ list_add_rcu(&drhd->list, &dmar_drhd_units);
}
static int __init dmar_parse_one_dev_scope(struct acpi_dmar_device_scope *scope,
- struct pci_dev **dev, u16 segment)
+ struct pci_dev __rcu **dev, u16 segment)
{
struct pci_bus *bus;
struct pci_dev *pdev = NULL;
@@ -122,7 +122,9 @@ static int __init dmar_parse_one_dev_scope(struct acpi_dmar_device_scope *scope,
pci_name(pdev));
return -EINVAL;
}
- *dev = pdev;
+
+ rcu_assign_pointer(*dev, pdev);
+
return 0;
}
@@ -149,7 +151,7 @@ void *dmar_alloc_dev_scope(void *start, void *end, int *cnt)
}
int __init dmar_parse_dev_scope(void *start, void *end, int *cnt,
- struct pci_dev ***devices, u16 segment)
+ struct pci_dev __rcu ***devices, u16 segment)
{
struct acpi_dmar_device_scope *scope;
int index, ret;
@@ -177,7 +179,7 @@ int __init dmar_parse_dev_scope(void *start, void *end, int *cnt,
return 0;
}
-void dmar_free_dev_scope(struct pci_dev ***devices, int *cnt)
+void dmar_free_dev_scope(struct pci_dev __rcu ***devices, int *cnt)
{
int i;
struct pci_dev *tmp_dev;
@@ -186,9 +188,10 @@ void dmar_free_dev_scope(struct pci_dev ***devices, int *cnt)
for_each_active_dev_scope(*devices, *cnt, i, tmp_dev)
pci_dev_put(tmp_dev);
kfree(*devices);
- *devices = NULL;
- *cnt = 0;
}
+
+ *devices = NULL;
+ *cnt = 0;
}
/**
@@ -410,7 +413,7 @@ parse_dmar_table(void)
return ret;
}
-static int dmar_pci_device_match(struct pci_dev *devices[], int cnt,
+static int dmar_pci_device_match(struct pci_dev __rcu *devices[], int cnt,
struct pci_dev *dev)
{
int index;
@@ -431,11 +434,12 @@ static int dmar_pci_device_match(struct pci_dev *devices[], int cnt,
struct dmar_drhd_unit *
dmar_find_matched_drhd_unit(struct pci_dev *dev)
{
- struct dmar_drhd_unit *dmaru = NULL;
+ struct dmar_drhd_unit *dmaru;
struct acpi_dmar_hardware_unit *drhd;
dev = pci_physfn(dev);
+ rcu_read_lock();
for_each_drhd_unit(dmaru) {
drhd = container_of(dmaru->hdr,
struct acpi_dmar_hardware_unit,
@@ -443,14 +447,17 @@ dmar_find_matched_drhd_unit(struct pci_dev *dev)
if (dmaru->include_all &&
drhd->segment == pci_domain_nr(dev->bus))
- return dmaru;
+ goto out;
if (dmar_pci_device_match(dmaru->devices,
dmaru->devices_cnt, dev))
- return dmaru;
+ goto out;
}
+ dmaru = NULL;
+out:
+ rcu_read_unlock();
- return NULL;
+ return dmaru;
}
int __init dmar_dev_scope_init(void)
diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 50d639a..e1679a6 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -385,14 +385,14 @@ 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 */
+ struct pci_dev __rcu **devices; /* target devices */
int devices_cnt; /* target device count */
};
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 */
+ struct pci_dev __rcu **devices; /* target devices */
int devices_cnt; /* target device count */
u8 include_all:1; /* include all ports */
};
@@ -634,12 +634,15 @@ static void domain_update_iommu_superpage(struct dmar_domain *domain)
}
/* set iommu_superpage to the smallest common denominator */
+ rcu_read_lock();
for_each_active_iommu(iommu, drhd) {
mask &= cap_super_page_val(iommu->cap);
if (!mask) {
break;
}
}
+ rcu_read_unlock();
+
domain->iommu_superpage = fls(mask);
}
@@ -658,6 +661,7 @@ static struct intel_iommu *device_to_iommu(int segment, u8 bus, u8 devfn)
struct pci_dev *dev;
int i;
+ rcu_read_lock();
for_each_active_iommu(iommu, drhd) {
if (segment != drhd->segment)
continue;
@@ -677,6 +681,7 @@ static struct intel_iommu *device_to_iommu(int segment, u8 bus, u8 devfn)
}
iommu = NULL;
out:
+ rcu_read_unlock();
return iommu;
}
@@ -1535,10 +1540,12 @@ static void domain_exit(struct dmar_domain *domain)
dma_pte_free_pagetable(domain, 0, DOMAIN_MAX_PFN(domain->gaw));
/* clear attached or cached domains */
+ rcu_read_lock();
for_each_active_iommu(iommu, drhd)
if (domain->flags & DOMAIN_FLAG_VIRTUAL_MACHINE ||
test_bit(iommu->seq_id, domain->iommu_bmp))
iommu_detach_domain(domain, iommu);
+ rcu_read_unlock();
free_domain_mem(domain);
}
@@ -2338,6 +2345,7 @@ static bool device_has_rmrr(struct pci_dev *dev)
struct pci_dev *tmp;
int i;
+ rcu_read_lock();
for_each_rmrr_units(rmrr) {
/*
* Return TRUE if this RMRR contains the device that
@@ -2346,9 +2354,11 @@ static bool device_has_rmrr(struct pci_dev *dev)
for_each_active_dev_scope(rmrr->devices,
rmrr->devices_cnt, i, tmp)
if (tmp == dev) {
+ rcu_read_unlock();
return true;
}
}
+ rcu_read_unlock();
return false;
}
@@ -3512,7 +3522,7 @@ int __init dmar_parse_one_atsr(struct acpi_dmar_header *hdr)
atsru->hdr = hdr;
atsru->include_all = atsr->flags & 0x1;
- list_add(&atsru->list, &dmar_atsr_units);
+ list_add_rcu(&atsru->list, &dmar_atsr_units);
return 0;
}
@@ -3574,6 +3584,7 @@ int dmar_find_matched_atsr_unit(struct pci_dev *dev)
if (!bridge)
return 0;
+ rcu_read_lock();
list_for_each_entry_rcu(atsru, &dmar_atsr_units, list) {
atsr = container_of(atsru->hdr, struct acpi_dmar_atsr, header);
if (atsr->segment != pci_domain_nr(dev->bus))
@@ -3588,6 +3599,7 @@ int dmar_find_matched_atsr_unit(struct pci_dev *dev)
}
ret = 0;
out:
+ rcu_read_unlock();
return ret;
}
@@ -3604,7 +3616,7 @@ int __init dmar_parse_rmrr_atsr_dev(void)
return ret;
}
- list_for_each_entry(atsr, &dmar_atsr_units, list) {
+ list_for_each_entry_rcu(atsr, &dmar_atsr_units, list) {
ret = atsr_parse_dev(atsr);
if (ret)
return ret;
diff --git a/include/linux/dmar.h b/include/linux/dmar.h
index 8f06a01..bedebab 100644
--- a/include/linux/dmar.h
+++ b/include/linux/dmar.h
@@ -26,6 +26,7 @@
#include <linux/msi.h>
#include <linux/irqreturn.h>
#include <linux/rwsem.h>
+#include <linux/rcupdate.h>
struct acpi_dmar_header;
@@ -41,7 +42,7 @@ 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 */
+ struct pci_dev __rcu **devices;/* target device array */
int devices_cnt; /* target device count */
u16 segment; /* PCI domain */
u8 ignored:1; /* ignore drhd */
@@ -53,22 +54,31 @@ extern struct rw_semaphore dmar_global_lock;
extern struct list_head dmar_drhd_units;
#define for_each_drhd_unit(drhd) \
- list_for_each_entry(drhd, &dmar_drhd_units, list)
+ list_for_each_entry_rcu(drhd, &dmar_drhd_units, list)
#define for_each_active_drhd_unit(drhd) \
- list_for_each_entry(drhd, &dmar_drhd_units, list) \
+ list_for_each_entry_rcu(drhd, &dmar_drhd_units, list) \
if (drhd->ignored) {} else
#define for_each_active_iommu(i, drhd) \
- list_for_each_entry(drhd, &dmar_drhd_units, list) \
+ list_for_each_entry_rcu(drhd, &dmar_drhd_units, list) \
if (i=drhd->iommu, drhd->ignored) {} else
#define for_each_iommu(i, drhd) \
- list_for_each_entry(drhd, &dmar_drhd_units, list) \
+ list_for_each_entry_rcu(drhd, &dmar_drhd_units, list) \
if (i=drhd->iommu, 0) {} else
+static inline bool dmar_rcu_check(void)
+{
+ return rwsem_is_locked(&dmar_global_lock) ||
+ system_state == SYSTEM_BOOTING;
+}
+
+#define dmar_rcu_dereference(p) rcu_dereference_check((p), dmar_rcu_check())
+
#define for_each_dev_scope(a, c, p, d) \
- for ((p) = 0; ((d) = (p) < (c) ? (a)[(p)] : NULL, (p) < (c)); (p)++)
+ for ((p) = 0; ((d) = (p) < (c) ? dmar_rcu_dereference((a)[(p)]) : \
+ NULL, (p) < (c)); (p)++)
#define for_each_active_dev_scope(a, c, p, d) \
for_each_dev_scope((a), (c), (p), (d)) if (!(d)) { continue; } else
@@ -78,6 +88,7 @@ extern int dmar_dev_scope_init(void);
extern int dmar_parse_dev_scope(void *start, void *end, int *cnt,
struct pci_dev ***devices, u16 segment);
extern void *dmar_alloc_dev_scope(void *start, void *end, int *cnt);
+extern void dmar_free_dev_scope(struct pci_dev __rcu ***devices, int *cnt);
extern void dmar_free_dev_scope(struct pci_dev ***devices, int *cnt);
/* Intel IOMMU detection */
--
1.7.10.4
--
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