Prior to these IOMMU patches, the passthrough option
could not be used because it would cause the kernel to
panic. Provide an indication that a kernel is capable
of handling passthrough mode through the introduction
of a specific variable name. This allows automatic
configuration utilities to set the "iommu=pt" kernel
cmdline option safely.
Signed-off-by: Mike Travis <[email protected]>
Acked-by: Dimitri Sivanich <[email protected]>
---
drivers/pci/intel-iommu.c | 4 ++++
1 file changed, 4 insertions(+)
--- linux.orig/drivers/pci/intel-iommu.c
+++ linux/drivers/pci/intel-iommu.c
@@ -390,6 +390,9 @@ static int dmar_map_gfx = 1;
static int dmar_forcedac;
static int intel_iommu_strict;
+/* specifically named variable that indicates "iommu=pt" is available */
+static int __initdata intel_iommu_64bit_pt;
+
#define DUMMY_DEVICE_DOMAIN_INFO ((struct device_domain_info *)(-1))
static DEFINE_SPINLOCK(device_domain_lock);
static LIST_HEAD(device_domain_list);
@@ -425,6 +428,7 @@ static int __init intel_iommu_setup(char
while (*str == ',')
str++;
}
+ intel_iommu_64bit_pt = 1;
return 0;
}
__setup("intel_iommu=", intel_iommu_setup);
--
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