iommu/vt-d: Check if domain->pgd was allocated

[ Upstream commit 3ee9eca760e7d0b68c55813243de66bbb499dc3b ]

There is a couple of places where on domain_init() failure domain_exit()
is called. While currently domain_init() can fail only if
alloc_pgtable_page() has failed.

Make domain_exit() check if domain->pgd present, before calling
domain_unmap(), as it theoretically should crash on clearing pte entries
in dma_pte_clear_level().

Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Lu Baolu <baolu.lu@linux.intel.com>
Cc: iommu@lists.linux-foundation.org
Signed-off-by: Dmitry Safonov <dima@arista.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>

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 2101601adf57d20dbe0f5a210f2e88854a822ee4..1ad24367373f416bf367d60b03da6b22b74bc297 100644 (file)
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -1900,7 +1900,6 @@ static int domain_init(struct dmar_domain *domain, struct intel_iommu *iommu,
 
 static void domain_exit(struct dmar_domain *domain)
 {
-       struct page *freelist;
 
        /* Remove associated devices and clear attached or cached domains */
        rcu_read_lock();
@@ -1910,9 +1909,12 @@ static void domain_exit(struct dmar_domain *domain)
        /* destroy iovas */
        put_iova_domain(&domain->iovad);
 
-       freelist = domain_unmap(domain, 0, DOMAIN_MAX_PFN(domain->gaw));
+       if (domain->pgd) {
+               struct page *freelist;
 
-       dma_free_pagelist(freelist);
+               freelist = domain_unmap(domain, 0, DOMAIN_MAX_PFN(domain->gaw));
+               dma_free_pagelist(freelist);
+       }
 
        free_domain_mem(domain);
 }