lkml.org 
[lkml]   [2019]   [Jun]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH v6 2/7] iommu/vt-d: Duplicate iommu_resv_region objects per device list
Date
intel_iommu_get_resv_regions() aims to return the list of
reserved regions accessible by a given @device. However several
devices can access the same reserved memory region and when
building the list it is not safe to use a single iommu_resv_region
object, whose container is the RMRR. This iommu_resv_region must
be duplicated per device reserved region list.

Let's remove the struct iommu_resv_region from the RMRR unit
and allocate the iommu_resv_region directly in
intel_iommu_get_resv_regions(). We hold the dmar_global_lock instead
of the rcu-lock to allow sleeping.

Fixes: 0659b8dc45a6 ("iommu/vt-d: Implement reserved region get/put callbacks")
Signed-off-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>

---
v5 -> v6:
- added space between | operands
- dmar_global_lock down_read/up_read instead of write
- added Lu's R-b

v4 -> v5
- replace rcu-lock by the dmar_global_lock
---
drivers/iommu/intel-iommu.c | 34 +++++++++++++++++-----------------
1 file changed, 17 insertions(+), 17 deletions(-)

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index a209199f3af6..4dc012966964 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -322,7 +322,6 @@ struct dmar_rmrr_unit {
u64 end_address; /* reserved end address */
struct dmar_dev_scope *devices; /* target devices */
int devices_cnt; /* target device count */
- struct iommu_resv_region *resv; /* reserved region handle */
};

struct dmar_atsr_unit {
@@ -4205,7 +4204,6 @@ static inline void init_iommu_pm_ops(void) {}
int __init dmar_parse_one_rmrr(struct acpi_dmar_header *header, void *arg)
{
struct acpi_dmar_reserved_memory *rmrr;
- int prot = DMA_PTE_READ|DMA_PTE_WRITE;
struct dmar_rmrr_unit *rmrru;
size_t length;

@@ -4219,22 +4217,16 @@ int __init dmar_parse_one_rmrr(struct acpi_dmar_header *header, void *arg)
rmrru->end_address = rmrr->end_address;

length = rmrr->end_address - rmrr->base_address + 1;
- rmrru->resv = iommu_alloc_resv_region(rmrr->base_address, length, prot,
- IOMMU_RESV_DIRECT);
- if (!rmrru->resv)
- goto free_rmrru;

rmrru->devices = dmar_alloc_dev_scope((void *)(rmrr + 1),
((void *)rmrr) + rmrr->header.length,
&rmrru->devices_cnt);
if (rmrru->devices_cnt && rmrru->devices == NULL)
- goto free_all;
+ goto free_rmrru;

list_add(&rmrru->list, &dmar_rmrr_units);

return 0;
-free_all:
- kfree(rmrru->resv);
free_rmrru:
kfree(rmrru);
out:
@@ -4452,7 +4444,6 @@ static void intel_iommu_free_dmars(void)
list_for_each_entry_safe(rmrru, rmrr_n, &dmar_rmrr_units, list) {
list_del(&rmrru->list);
dmar_free_dev_scope(&rmrru->devices, &rmrru->devices_cnt);
- kfree(rmrru->resv);
kfree(rmrru);
}

@@ -5470,22 +5461,33 @@ static void intel_iommu_remove_device(struct device *dev)
static void intel_iommu_get_resv_regions(struct device *device,
struct list_head *head)
{
+ int prot = DMA_PTE_READ | DMA_PTE_WRITE;
struct iommu_resv_region *reg;
struct dmar_rmrr_unit *rmrr;
struct device *i_dev;
int i;

- rcu_read_lock();
+ down_read(&dmar_global_lock);
for_each_rmrr_units(rmrr) {
for_each_active_dev_scope(rmrr->devices, rmrr->devices_cnt,
i, i_dev) {
+ struct iommu_resv_region *resv;
+ size_t length;
+
if (i_dev != device)
continue;

- list_add_tail(&rmrr->resv->list, head);
+ length = rmrr->end_address - rmrr->base_address + 1;
+ resv = iommu_alloc_resv_region(rmrr->base_address,
+ length, prot,
+ IOMMU_RESV_DIRECT);
+ if (!resv)
+ break;
+
+ list_add_tail(&resv->list, head);
}
}
- rcu_read_unlock();
+ up_read(&dmar_global_lock);

reg = iommu_alloc_resv_region(IOAPIC_RANGE_START,
IOAPIC_RANGE_END - IOAPIC_RANGE_START + 1,
@@ -5500,10 +5502,8 @@ static void intel_iommu_put_resv_regions(struct device *dev,
{
struct iommu_resv_region *entry, *next;

- list_for_each_entry_safe(entry, next, head, list) {
- if (entry->type == IOMMU_RESV_MSI)
- kfree(entry);
- }
+ list_for_each_entry_safe(entry, next, head, list)
+ kfree(entry);
}

int intel_iommu_enable_pasid(struct intel_iommu *iommu, struct device *dev)
--
2.20.1
\
 
 \ /
  Last update: 2019-06-03 08:55    [W:0.053 / U:1.052 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site