x86/amd-iommu: Add core functions for pd allocation/freeing

This patch factors some code of protection domain allocation
into seperate functions. This way the logic can be used to
allocate the passthrough domain later. As a side effect this
patch fixes an unlikely domain id leakage bug.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>

1 files changed, 32 insertions, 4 deletions

diff --git a/arch/x86/kernel/amd_iommu.c b/arch/x86/kernel/amd_iommu.c
index 6c99f5037801..0934348abfad 100644
--- a/arch/x86/kernel/amd_iommu.c
+++ b/arch/x86/kernel/amd_iommu.c
@@ -1988,19 +1988,47 @@ static void cleanup_domain(struct protection_domain *domain)
         write_unlock_irqrestore(&amd_iommu_devtable_lock, flags);
 }
 
-static int amd_iommu_domain_init(struct iommu_domain *dom)
+static void protection_domain_free(struct protection_domain *domain)
+{
+        if (!domain)
+                return;
+
+        if (domain->id)
+                domain_id_free(domain->id);
+
+        kfree(domain);
+}
+
+static struct protection_domain *protection_domain_alloc(void)
 {
         struct protection_domain *domain;
 
         domain = kzalloc(sizeof(*domain), GFP_KERNEL);
         if (!domain)
-                return -ENOMEM;
+                return NULL;
 
         spin_lock_init(&domain->lock);
-        domain->mode = PAGE_MODE_3_LEVEL;
         domain->id = domain_id_alloc();
         if (!domain->id)
+                goto out_err;
+
+        return domain;
+
+out_err:
+        kfree(domain);
+
+        return NULL;
+}
+
+static int amd_iommu_domain_init(struct iommu_domain *dom)
+{
+        struct protection_domain *domain;
+
+        domain = protection_domain_alloc();
+        if (!domain)
                 goto out_free;
+
+        domain->mode    = PAGE_MODE_3_LEVEL;
         domain->pt_root = (void *)get_zeroed_page(GFP_KERNEL);
         if (!domain->pt_root)
                 goto out_free;
@@ -2010,7 +2038,7 @@ static int amd_iommu_domain_init(struct iommu_domain *dom)
         return 0;
 
 out_free:
-        kfree(domain);
+        protection_domain_free(domain);
 
         return -ENOMEM;
 }