[RFC PATCH 05/11] powerpc/svm: Don't release SWIOTLB buffers on secure guests

From: Thiago Jung Bauermann
Date: Fri Aug 24 2018 - 12:26:26 EST

From: Anshuman Khandual <khandual@xxxxxxxxxxxxxxxxxx>

Even though SWIOTLB slab gets allocated and initialized on each powerpc
platform with swiotlb_init(), it gets released away again on all server
platforms because ppc_swiotlb_enable variable never gets set. Secure
guests would require SWIOTLB DMA API support for virtio bounce buffering
purpose. Hence retain the allocated buffer by setting ppc_swiotlb_enable
variable for secure guests on Ultravisor platforms.

Signed-off-by: Anshuman Khandual <khandual@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Thiago Jung Bauermann <bauerman@xxxxxxxxxxxxx>
arch/powerpc/kernel/svm.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/arch/powerpc/kernel/svm.c b/arch/powerpc/kernel/svm.c
index eab2a64d8643..891db2de8c04 100644
--- a/arch/powerpc/kernel/svm.c
+++ b/arch/powerpc/kernel/svm.c
@@ -16,6 +16,7 @@ static int __init init_svm(void)
if (!is_svm_platform())
return 0;

+ ppc_swiotlb_enable = 1;

return 0;