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authorJoerg Roedel <jroedel@suse.de>2019-10-18 11:34:22 +0200
committerJoerg Roedel <jroedel@suse.de>2019-10-18 16:52:37 +0200
commit46ac18c347b00be29b265c28209b0f3c38a1f142 (patch)
treeec59ad83cad68ff3994928323dc38762397db82c /drivers
parentec21f17a9437e11bb29e5fa375aa31b472793c15 (diff)
iommu/amd: Check PM_LEVEL_SIZE() condition in locked section
The increase_address_space() function has to check the PM_LEVEL_SIZE() condition again under the domain->lock to avoid a false trigger of the WARN_ON_ONCE() and to avoid that the address space is increase more often than necessary. Reported-by: Qian Cai <cai@lca.pw> Fixes: 754265bcab78 ("iommu/amd: Fix race in increase_address_space()") Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com> Signed-off-by: Joerg Roedel <jroedel@suse.de>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/iommu/amd_iommu.c7
1 files changed, 4 insertions, 3 deletions
diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index bcd89ea50a8b..dd555078258c 100644
--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -1464,6 +1464,7 @@ static void free_pagetable(struct protection_domain *domain)
* to 64 bits.
*/
static bool increase_address_space(struct protection_domain *domain,
+ unsigned long address,
gfp_t gfp)
{
unsigned long flags;
@@ -1472,8 +1473,8 @@ static bool increase_address_space(struct protection_domain *domain,
spin_lock_irqsave(&domain->lock, flags);
- if (WARN_ON_ONCE(domain->mode == PAGE_MODE_6_LEVEL))
- /* address space already 64 bit large */
+ if (address <= PM_LEVEL_SIZE(domain->mode) ||
+ WARN_ON_ONCE(domain->mode == PAGE_MODE_6_LEVEL))
goto out;
pte = (void *)get_zeroed_page(gfp);
@@ -1506,7 +1507,7 @@ static u64 *alloc_pte(struct protection_domain *domain,
BUG_ON(!is_power_of_2(page_size));
while (address > PM_LEVEL_SIZE(domain->mode))
- *updated = increase_address_space(domain, gfp) || *updated;
+ *updated = increase_address_space(domain, address, gfp) || *updated;
level = domain->mode - 1;
pte = &domain->pt_root[PM_LEVEL_INDEX(level, address)];