[PATCH AUTOSEL 4.19 405/671] iommu/vt-d: Duplicate iommu_resv_region objects per device list

Sasha Levin
2020-01-16T18:52:19Z

From: Eric Auger <eric.auger@redhat.com>

[ Upstream commit 5f64ce5411b467f1cfea6c63e2494c22b773582b ]

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>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
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 abbbc614c522..9df3b8441227 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -387,7 +387,6 @@ 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 {
@@ -4185,7 +4184,6 @@ 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;

@@ -4199,22 +4197,16 @@ 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:
@@ -4432,7 +4424,6 @@ 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);
}

@@ -5206,22 +5197,33 @@ 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,
@@ -5236,10 +5238,8 @@ 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);
}

#ifdef CONFIG_INTEL_IOMMU_SVM
--
2.20.1