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-rw-r--r--Documentation/kernel-parameters.txt2
-rw-r--r--arch/x86/kernel/amd_iommu_init.c6
2 files changed, 8 insertions, 0 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 839b21b0699a..0c6c56076d19 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -324,6 +324,8 @@ and is between 256 and 4096 characters. It is defined in the file
324 they are unmapped. Otherwise they are 324 they are unmapped. Otherwise they are
325 flushed before they will be reused, which 325 flushed before they will be reused, which
326 is a lot of faster 326 is a lot of faster
327 off - do not initialize any AMD IOMMU found in
328 the system
327 329
328 amijoy.map= [HW,JOY] Amiga joystick support 330 amijoy.map= [HW,JOY] Amiga joystick support
329 Map of devices attached to JOY0DAT and JOY1DAT 331 Map of devices attached to JOY0DAT and JOY1DAT
diff --git a/arch/x86/kernel/amd_iommu_init.c b/arch/x86/kernel/amd_iommu_init.c
index 6360abf993d4..3bacb4d0844c 100644
--- a/arch/x86/kernel/amd_iommu_init.c
+++ b/arch/x86/kernel/amd_iommu_init.c
@@ -120,6 +120,7 @@ struct ivmd_header {
120bool amd_iommu_dump; 120bool amd_iommu_dump;
121 121
122static int __initdata amd_iommu_detected; 122static int __initdata amd_iommu_detected;
123static bool __initdata amd_iommu_disabled;
123 124
124u16 amd_iommu_last_bdf; /* largest PCI device id we have 125u16 amd_iommu_last_bdf; /* largest PCI device id we have
125 to handle */ 126 to handle */
@@ -1372,6 +1373,9 @@ void __init amd_iommu_detect(void)
1372 if (no_iommu || (iommu_detected && !gart_iommu_aperture)) 1373 if (no_iommu || (iommu_detected && !gart_iommu_aperture))
1373 return; 1374 return;
1374 1375
1376 if (amd_iommu_disabled)
1377 return;
1378
1375 if (acpi_table_parse("IVRS", early_amd_iommu_detect) == 0) { 1379 if (acpi_table_parse("IVRS", early_amd_iommu_detect) == 0) {
1376 iommu_detected = 1; 1380 iommu_detected = 1;
1377 amd_iommu_detected = 1; 1381 amd_iommu_detected = 1;
@@ -1401,6 +1405,8 @@ static int __init parse_amd_iommu_options(char *str)
1401 for (; *str; ++str) { 1405 for (; *str; ++str) {
1402 if (strncmp(str, "fullflush", 9) == 0) 1406 if (strncmp(str, "fullflush", 9) == 0)
1403 amd_iommu_unmap_flush = true; 1407 amd_iommu_unmap_flush = true;
1408 if (strncmp(str, "off", 3) == 0)
1409 amd_iommu_disabled = true;
1404 } 1410 }
1405 1411
1406 return 1; 1412 return 1;