[PATCH 0/2] iommu/vt-d: Small fixes for 5.2-rc1

[PATCH 0/2] iommu/vt-d: Small fixes for 5.2-rc1

[Lu Baolu]

Hi Joerg,

This includes two small fixes for virtual IOMMU running in
qemu enviroment. On bare metal, we always have an dedicated
IOMMU for Intel integrated graphic device. And some aspects
of the driver was designed according to this. Unfortunately,
in qemu environment, the virtual IOMMU has only a single
include-all IOMMU engine, as the result some interfaces don't
work as expected anymore. This includes two fixes for this.

Best regards,
Lu Baolu

Lu Baolu (2):
  iommu/vt-d: Set intel_iommu_gfx_mapped correctly
  iommu/vt-d: Make kernel parameter igfx_off work with vIOMMU

 drivers/iommu/intel-iommu.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

-- 
2.17.1

[PATCH 1/2] iommu/vt-d: Set intel_iommu_gfx_mapped correctly

[Lu Baolu]

The intel_iommu_gfx_mapped flag is exported by the Intel
IOMMU driver to indicate whether an IOMMU is used for the
graphic device. In a virtualized IOMMU environment (e.g.
QEMU), an include-all IOMMU is used for graphic device.
This flag is found to be clear even the IOMMU is used.

Cc: Ashok Raj <ashok.raj@intel.com>
Cc: Jacob Pan <jacob.jun.pan@linux.intel.com>
Cc: Kevin Tian <kevin.tian@intel.com>
Reported-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Fixes: c0771df8d5297 ("intel-iommu: Export a flag indicating that the IOMMU is used for iGFX.")
Suggested-by: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
---
 drivers/iommu/intel-iommu.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index e0c0febc6fa5..00ad00193883 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -4068,9 +4068,7 @@ static void __init init_no_remapping_devices(void)
 
 		/* This IOMMU has *only* gfx devices. Either bypass it or
 		   set the gfx_mapped flag, as appropriate */
-		if (dmar_map_gfx) {
-			intel_iommu_gfx_mapped = 1;
-		} else {
+		if (!dmar_map_gfx) {
 			drhd->ignored = 1;
 			for_each_active_dev_scope(drhd->devices,
 						  drhd->devices_cnt, i, dev)
@@ -4909,6 +4907,9 @@ int __init intel_iommu_init(void)
 		goto out_free_reserved_range;
 	}
 
+	if (dmar_map_gfx)
+		intel_iommu_gfx_mapped = 1;
+
 	init_no_remapping_devices();
 
 	ret = init_dmars();
-- 
2.17.1

[PATCH 2/2] iommu/vt-d: Make kernel parameter igfx_off work with vIOMMU

[Lu Baolu]

The kernel parameter igfx_off is used by users to disable
DMA remapping for the Intel integrated graphic device. It
was designed for bare metal cases where a dedicated IOMMU
is used for graphic. This doesn't apply to virtual IOMMU
case where an include-all IOMMU is used.  This makes the
kernel parameter work with virtual IOMMU as well.

Cc: Ashok Raj <ashok.raj@intel.com>
Cc: Jacob Pan <jacob.jun.pan@linux.intel.com>
Suggested-by: Kevin Tian <kevin.tian@intel.com>
Fixes: c0771df8d5297 ("intel-iommu: Export a flag indicating that the IOMMU is used for iGFX.")
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Tested-by: Zhenyu Wang <zhenyuw@linux.intel.com>
---
 drivers/iommu/intel-iommu.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 00ad00193883..e078b13ce3d8 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -3415,9 +3415,12 @@ static int __init init_dmars(void)
 		iommu_identity_mapping |= IDENTMAP_ALL;
 
 #ifdef CONFIG_INTEL_IOMMU_BROKEN_GFX_WA
-	iommu_identity_mapping |= IDENTMAP_GFX;
+	dmar_map_gfx = 0;
 #endif
 
+	if (!dmar_map_gfx)
+		iommu_identity_mapping |= IDENTMAP_GFX;
+
 	check_tylersburg_isoch();
 
 	if (iommu_identity_mapping) {
-- 
2.17.1

Re: [PATCH 0/2] iommu/vt-d: Small fixes for 5.2-rc1

[Joerg Roedel]

On Thu, May 02, 2019 at 09:34:24AM +0800, Lu Baolu wrote:
> Lu Baolu (2):
>   iommu/vt-d: Set intel_iommu_gfx_mapped correctly
>   iommu/vt-d: Make kernel parameter igfx_off work with vIOMMU

Applied both, thanks.