| Message ID | 1473691764-29424-7-git-send-email-vladimir.murzin@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Mon, Sep 12, 2016 at 03:49:20PM +0100, Vladimir Murzin wrote: > 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. > > Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com> Acked-by: Christoffer Dall <christoffer.dall@linaro.org> > --- > virt/kvm/arm/vgic/vgic-mmio-v3.c | 2 +- > virt/kvm/arm/vgic/vgic-mmio.h | 2 +- > 2 files changed, 2 insertions(+), 2 deletions(-) > > diff --git a/virt/kvm/arm/vgic/vgic-mmio-v3.c b/virt/kvm/arm/vgic/vgic-mmio-v3.c > index 6385ed5..0d3c76a 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); > diff --git a/virt/kvm/arm/vgic/vgic-mmio.h b/virt/kvm/arm/vgic/vgic-mmio.h > index 0b3ecf9..80f92ce 100644 > --- a/virt/kvm/arm/vgic/vgic-mmio.h > +++ b/virt/kvm/arm/vgic/vgic-mmio.h > @@ -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, > -- > 1.7.9.5 >
On 12/09/16 15:49, Vladimir Murzin wrote: > 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. > > Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com> > --- > virt/kvm/arm/vgic/vgic-mmio-v3.c | 2 +- > virt/kvm/arm/vgic/vgic-mmio.h | 2 +- > 2 files changed, 2 insertions(+), 2 deletions(-) Acked-by: Marc Zyngier <marc.zyngier@arm.com> M.
diff --git a/virt/kvm/arm/vgic/vgic-mmio-v3.c b/virt/kvm/arm/vgic/vgic-mmio-v3.c index 6385ed5..0d3c76a 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); diff --git a/virt/kvm/arm/vgic/vgic-mmio.h b/virt/kvm/arm/vgic/vgic-mmio.h index 0b3ecf9..80f92ce 100644 --- a/virt/kvm/arm/vgic/vgic-mmio.h +++ b/virt/kvm/arm/vgic/vgic-mmio.h @@ -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,
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. Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com> --- virt/kvm/arm/vgic/vgic-mmio-v3.c | 2 +- virt/kvm/arm/vgic/vgic-mmio.h | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-)