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

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>

1 files changed, 5 insertions, 3 deletions

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 72c6d647bec9..bdaed2da8a55 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -1890,7 +1890,6 @@ 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 */
         domain_remove_dev_info(domain);
@@ -1898,9 +1897,12 @@ 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);
 }