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>

diff --git a/arch/x86/kernel/amd_iommu.c b/arch/x86/kernel/amd_iommu.c
index 6c99f50..0934348 100644 (file)
--- 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;
 }