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KVM: arm: vgic: Support 64-bit data manipulation on 32-bit host systems

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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>
This commit is contained in:
Vladimir Murzin 2016-09-12 15:49:20 +01:00 committed by Christoffer Dall
parent e533a37f7b
commit d7d0a11e44
2 changed files with 2 additions and 2 deletions
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2
virt/kvm/arm/vgic/vgic-mmio-v3.c
View File

@ -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);

2
virt/kvm/arm/vgic/vgic-mmio.h
View File

@ -96,7 +96,7 @@ unsigned long vgic_data_mmio_bus_to_host(const void *val, unsigned int len);
void vgic_data_host_to_mmio_bus(void *buf, unsigned int len,
unsigned long data);
unsigned long extract_bytes(unsigned long data, unsigned int offset,
unsigned long extract_bytes(u64 data, unsigned int offset,
unsigned int num);
u64 update_64bit_reg(u64 reg, unsigned int offset, unsigned int len,