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[RFC,v2,2/2] powerpc/pseries/iommu: Use dma_iommu_ops for Secure VMs aswell.

Message ID 1573254011-1604-3-git-send-email-linuxram@us.ibm.com (mailing list archive)
State Superseded
Headers show
Series Enable IOMMU support for pseries Secure VMs | expand

Checks

Context Check Description
snowpatch_ozlabs/apply_patch success Successfully applied on branch powerpc/merge (85c5b0984ebb104ec7a0a853ec1e63c19f500313)
snowpatch_ozlabs/build-ppc64le success Build succeeded
snowpatch_ozlabs/build-ppc64be success Build succeeded
snowpatch_ozlabs/build-ppc64e success Build succeeded
snowpatch_ozlabs/build-pmac32 success Build succeeded
snowpatch_ozlabs/checkpatch fail total: 2 errors, 0 warnings, 0 checks, 23 lines checked

Commit Message

Ram Pai Nov. 8, 2019, 11 p.m. UTC
Commit edea902c1c1e disabled dma_iommu_ops path, for secure VMs. The
rationale for disabling the dma_iommu_ops path, was to enable use of the
dma_direct path, which had inbuilt support for bounce-buffering through
SWIOTLB.

However dma_iommu_ops is functionally much richer. Depending on the
capabilities of the platform, it can handle direct DMA; with or without
bounce buffering, and it can handle indirect DMA. Hence its better to
leverage the richer functionality supported by dma_iommu_ops.

Revert edea902c1c1e and renable dma_iommu_ops path for pseries Secure
VMs.

Signed-off-by: Ram Pai <linuxram@us.ibm.com>
---
 arch/powerpc/platforms/pseries/iommu.c | 11 +----------
 1 file changed, 1 insertion(+), 10 deletions(-)
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Patch

diff --git a/arch/powerpc/platforms/pseries/iommu.c b/arch/powerpc/platforms/pseries/iommu.c
index a302aaa..3ffcb54 100644
--- a/arch/powerpc/platforms/pseries/iommu.c
+++ b/arch/powerpc/platforms/pseries/iommu.c
@@ -36,7 +36,6 @@ 
 #include <asm/udbg.h>
 #include <asm/mmzone.h>
 #include <asm/plpar_wrappers.h>
-#include <asm/svm.h>
 #include <asm/ultravisor.h>
 
 #include "pseries.h"
@@ -1336,15 +1335,7 @@  void iommu_init_early_pSeries(void)
 	of_reconfig_notifier_register(&iommu_reconfig_nb);
 	register_memory_notifier(&iommu_mem_nb);
 
-	/*
-	 * Secure guest memory is inacessible to devices so regular DMA isn't
-	 * possible.
-	 *
-	 * In that case keep devices' dma_map_ops as NULL so that the generic
-	 * DMA code path will use SWIOTLB to bounce buffers for DMA.
-	 */
-	if (!is_secure_guest())
-		set_pci_dma_ops(&dma_iommu_ops);
+	set_pci_dma_ops(&dma_iommu_ops);
 }
 
 static int __init disable_multitce(char *str)