x86/amd-iommu: Introduce increase_address_space function

This function will be used to increase the address space
size of a protection domain.

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

1 files changed, 27 insertions, 0 deletions

diff --git a/arch/x86/kernel/amd_iommu.c b/arch/x86/kernel/amd_iommu.c
index 5eab6a84b9cc..fc97b51f0287 100644
--- a/arch/x86/kernel/amd_iommu.c
+++ b/arch/x86/kernel/amd_iommu.c
@@ -1325,6 +1325,33 @@ static void update_domain(struct protection_domain *domain)
 }
 
 /*
+ * This function is used to add another level to an IO page table. Adding
+ * another level increases the size of the address space by 9 bits to a size up
+ * to 64 bits.
+ */
+static bool increase_address_space(struct protection_domain *domain,
+				   gfp_t gfp)
+{
+	u64 *pte;
+
+	if (domain->mode == PAGE_MODE_6_LEVEL)
+		/* address space already 64 bit large */
+		return false;
+
+	pte = (void *)get_zeroed_page(gfp);
+	if (!pte)
+		return false;
+
+	*pte             = PM_LEVEL_PDE(domain->mode,
+					virt_to_phys(domain->pt_root));
+	domain->pt_root  = pte;
+	domain->mode    += 1;
+	domain->updated  = true;
+
+	return true;
+}
+
+/*
  * If the pte_page is not yet allocated this function is called
  */
 static u64* alloc_pte(struct protection_domain *dom,