linux-kernel - [PATCH 10/12] powerpc/pseries/iommu: Don't use dma_iommu

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Date:   Tue, 21 May 2019 01:49:10 -0300
From:   Thiago Jung Bauermann <bauerman@...ux.ibm.com>
To:     linuxppc-dev@...ts.ozlabs.org
Cc:     linux-kernel@...r.kernel.org, Alexey Kardashevskiy <aik@...abs.ru>,
        Anshuman Khandual <anshuman.linux@...il.com>,
        Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Christoph Hellwig <hch@....de>,
        Michael Ellerman <mpe@...erman.id.au>,
        Mike Anderson <andmike@...ux.ibm.com>,
        Paul Mackerras <paulus@...ba.org>,
        Ram Pai <linuxram@...ibm.com>,
        Claudio Carvalho <cclaudio@...ux.ibm.com>,
        Thiago Jung Bauermann <bauerman@...ux.ibm.com>
Subject: [PATCH 10/12] powerpc/pseries/iommu: Don't use dma_iommu_ops on secure guests

Secure guest memory is inacessible to devices so regular DMA isn't
possible.

In that case set devices' dma_map_ops to NULL so that the generic
DMA code path will use SWIOTLB and DMA to bounce buffers.

Signed-off-by: Thiago Jung Bauermann <bauerman@...ux.ibm.com>
---
 arch/powerpc/platforms/pseries/iommu.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/platforms/pseries/iommu.c b/arch/powerpc/platforms/pseries/iommu.c
index 03bbb299320e..7d9550edb700 100644
--- a/arch/powerpc/platforms/pseries/iommu.c
+++ b/arch/powerpc/platforms/pseries/iommu.c
@@ -50,6 +50,7 @@
 #include <asm/udbg.h>
 #include <asm/mmzone.h>
 #include <asm/plpar_wrappers.h>
+#include <asm/svm.h>
 
 #include "pseries.h"
 
@@ -1332,7 +1333,10 @@ void iommu_init_early_pSeries(void)
 	of_reconfig_notifier_register(&iommu_reconfig_nb);
 	register_memory_notifier(&iommu_mem_nb);
 
-	set_pci_dma_ops(&dma_iommu_ops);
+	if (is_secure_guest())
+		set_pci_dma_ops(NULL);
+	else
+		set_pci_dma_ops(&dma_iommu_ops);
 }
 
 static int __init disable_multitce(char *str)