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powerpc/pseries/dma: Enable SWIOTLB 

So far the pseries platforms has always been using IOMMU making
SWIOTLB unnecessary. Now we want secure guests which means devices can
only access certain areas of guest physical memory; we are going to
use SWIOTLB for this purpose.

This allows SWIOTLB for pseries. By default there is no change in
behavior.

This enables SWIOTLB when the "swiotlb" kernel parameter is set to
"force".

With the SWIOTLB enabled, the kernel creates a directly mapped DMA
window (using the usual DDW mechanism) and implements SWIOTLB on top
of that.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Alexey Kardashevskiy 2019-05-07 16:25:59 +10:00 committed by Michael Ellerman
parent efd176a04b
commit 1a047cc7e5
2 changed files with 6 additions and 0 deletions
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1
arch/powerpc/platforms/pseries/Kconfig
View File

@ -23,6 +23,7 @@ config PPC_PSERIES
select ARCH_RANDOM
select PPC_DOORBELL
select FORCE_SMP
select SWIOTLB
default y
config PPC_SPLPAR

5
arch/powerpc/platforms/pseries/setup.c
View File

@ -42,6 +42,7 @@
#include <linux/of.h>
#include <linux/of_pci.h>
#include <linux/memblock.h>
#include <linux/swiotlb.h>
#include <asm/mmu.h>
#include <asm/processor.h>
@ -71,6 +72,7 @@
#include <asm/isa-bridge.h>
#include <asm/security_features.h>
#include <asm/asm-const.h>
#include <asm/swiotlb.h>
#include "pseries.h"
#include "../../../../drivers/pci/pci.h"
@ -797,6 +799,9 @@ static void __init pSeries_setup_arch(void)
}
ppc_md.pcibios_root_bridge_prepare = pseries_root_bridge_prepare;
if (swiotlb_force == SWIOTLB_FORCE)
ppc_swiotlb_enable = 1;
}
static void pseries_panic(char *str)