[PATCH kernel 1/3] powerpc/pseries/iommu: Use dma_iommu_ops for Secure VM.

Alexey Kardashevskiy aik at ozlabs.ru
Fri Dec 13 19:45:35 AEDT 2019


From: Ram Pai <linuxram at us.ibm.com>

Commit edea902c1c1e ("powerpc/pseries/iommu: Don't use dma_iommu_ops on
		secure guests")
disabled dma_iommu_ops path, for secure VMs. Disabling dma_iommu_ops
path for secure VMs, helped enable dma_direct path.  This enabled
support for bounce-buffering through SWIOTLB.  However it fails to
operate when IOMMU is enabled, since I/O pages are not TCE mapped.

Reenable dma_iommu_ops path for pseries Secure VMs.  It handles all
cases including, TCE mapping I/O pages, in the presence of a
IOMMU.

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

diff --git a/arch/powerpc/platforms/pseries/iommu.c b/arch/powerpc/platforms/pseries/iommu.c
index 6ba081dd61c9..df7db33ca93b 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 "pseries.h"
 
@@ -1320,15 +1319,7 @@ 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)
-- 
2.17.1



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