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authorVladimir Murzin <vladimir.murzin@arm.com>2016-09-12 17:49:20 +0300
committerChristoffer Dall <christoffer.dall@linaro.org>2016-09-22 14:21:59 +0300
commitd7d0a11e44a1c6c1e61db7f305115f33be900704 (patch)
treeff8b15fe984d8c3f95cc7fca916979d955d45cf9 /virt/kvm/arm/vgic/vgic-mmio-v3.c
parente533a37f7b5ee5eb8b102cf0823e84cd6a7deb57 (diff)
downloadlinux-d7d0a11e44a1c6c1e61db7f305115f33be900704.tar.xz
KVM: arm: vgic: Support 64-bit data manipulation on 32-bit host systems
We have couple of 64-bit registers defined in GICv3 architecture, so unsigned long accesses to these registers will only access a single 32-bit part of that regitser. On the other hand these registers can't be accessed as 64-bit with a single instruction like ldrd/strd or ldmia/stmia if we run a 32-bit host because KVM does not support access to MMIO space done by these instructions. It means that a 32-bit guest accesses these registers in 32-bit chunks, so the only thing we need to do is to ensure that extract_bytes() always takes 64-bit data. Acked-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Diffstat (limited to 'virt/kvm/arm/vgic/vgic-mmio-v3.c')
-rw-r--r--virt/kvm/arm/vgic/vgic-mmio-v3.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/virt/kvm/arm/vgic/vgic-mmio-v3.c b/virt/kvm/arm/vgic/vgic-mmio-v3.c
index 6385ed5814b4..0d3c76a4208b 100644
--- a/virt/kvm/arm/vgic/vgic-mmio-v3.c
+++ b/virt/kvm/arm/vgic/vgic-mmio-v3.c
@@ -23,7 +23,7 @@
#include "vgic-mmio.h"
/* extract @num bytes at @offset bytes offset in data */
-unsigned long extract_bytes(unsigned long data, unsigned int offset,
+unsigned long extract_bytes(u64 data, unsigned int offset,
unsigned int num)
{
return (data >> (offset * 8)) & GENMASK_ULL(num * 8 - 1, 0);