From 46ac18c347b00be29b265c28209b0f3c38a1f142 Mon Sep 17 00:00:00 2001 From: Joerg Roedel Date: Fri, 18 Oct 2019 11:34:22 +0200 Subject: [PATCH] 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 Fixes: 754265bcab78 ("iommu/amd: Fix race in increase_address_space()") Reviewed-by: Jerry Snitselaar Signed-off-by: Joerg Roedel --- drivers/iommu/amd_iommu.c | 7 ++++--- 1 file 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)];