Intel IOMMU: Intel iommu cmdline option - forcedac
Introduce intel_iommu=forcedac commandline option. This option is helpful to
verify the pci device capability of handling physical dma'able address greater
than 4G.
Signed-off-by: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: Andi Kleen <ak@suse.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Muli Ben-Yehuda <muli@il.ibm.com>
Cc: "Siddha, Suresh B" <suresh.b.siddha@intel.com>
Cc: Arjan van de Ven <arjan@infradead.org>
Cc: Ashok Raj <ashok.raj@intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/pci/intel-iommu.c b/drivers/pci/intel-iommu.c
index 05630b4..cb24def 100644
--- a/drivers/pci/intel-iommu.c
+++ b/drivers/pci/intel-iommu.c
@@ -54,6 +54,7 @@
static int dmar_disabled;
static int __initdata dmar_map_gfx = 1;
+static int dmar_forcedac;
#define DUMMY_DEVICE_DOMAIN_INFO ((struct device_domain_info *)(-1))
static DEFINE_SPINLOCK(device_domain_lock);
@@ -71,6 +72,10 @@
dmar_map_gfx = 0;
printk(KERN_INFO
"Intel-IOMMU: disable GFX device mapping\n");
+ } else if (!strncmp(str, "forcedac", 8)) {
+ printk (KERN_INFO
+ "Intel-IOMMU: Forcing DAC for PCI devices\n");
+ dmar_forcedac = 1;
}
str += strcspn(str, ",");
@@ -1558,7 +1563,7 @@
start_addr = IOVA_START_ADDR;
- if (pdev->dma_mask <= DMA_32BIT_MASK) {
+ if ((pdev->dma_mask <= DMA_32BIT_MASK) || (dmar_forcedac)) {
iova = iommu_alloc_iova(domain, addr, size, start_addr,
pdev->dma_mask);
} else {