| Message ID | 1392183693-21238-7-git-send-email-victor.kamensky@linaro.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, Feb 11, 2014 at 09:41:32PM -0800, Victor Kamensky wrote: > According to recent clarifications of mmio.data array meaning - > the mmio.data array should hold bytes as they would appear in > memory. Vgic is little endian device. And in case of BE image > kernel side that emulates vgic, holds data in BE form. So we > need to byteswap cpu<->le32 vgic registers when we read/write them > from mmio.data[]. > > Change has no effect in LE case because cpu already runs in le32. > > Signed-off-by: Victor Kamensky <victor.kamensky@linaro.org> > --- > virt/kvm/arm/vgic.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/virt/kvm/arm/vgic.c b/virt/kvm/arm/vgic.c > index 685fc72..7e11458 100644 > --- a/virt/kvm/arm/vgic.c > +++ b/virt/kvm/arm/vgic.c > @@ -236,12 +236,12 @@ static void vgic_cpu_irq_clear(struct kvm_vcpu *vcpu, int irq) > > static u32 mmio_data_read(struct kvm_exit_mmio *mmio, u32 mask) > { > - return *((u32 *)mmio->data) & mask; > + return le32_to_cpu(*((u32 *)mmio->data)) & mask; > } > > static void mmio_data_write(struct kvm_exit_mmio *mmio, u32 mask, u32 value) > { > - *((u32 *)mmio->data) = value & mask; > + *((u32 *)mmio->data) = cpu_to_le32(value) & mask; > } > > /** > -- > 1.8.1.4 > I hate the fact that we have endianness handling code inside the vgic emulation, I would strongly prefer that the interface to the vgic code is a typed union, but, that being said, I haven't looked at how the changes to the code would look to accomplish that. You didn't reply to my same comment last time around, but did you ahve a look? The code here, with the ABI specification does look correct, so assuming that ABI specification gets merged: Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
diff --git a/virt/kvm/arm/vgic.c b/virt/kvm/arm/vgic.c index 685fc72..7e11458 100644 --- a/virt/kvm/arm/vgic.c +++ b/virt/kvm/arm/vgic.c @@ -236,12 +236,12 @@ static void vgic_cpu_irq_clear(struct kvm_vcpu *vcpu, int irq) static u32 mmio_data_read(struct kvm_exit_mmio *mmio, u32 mask) { - return *((u32 *)mmio->data) & mask; + return le32_to_cpu(*((u32 *)mmio->data)) & mask; } static void mmio_data_write(struct kvm_exit_mmio *mmio, u32 mask, u32 value) { - *((u32 *)mmio->data) = value & mask; + *((u32 *)mmio->data) = cpu_to_le32(value) & mask; } /**
According to recent clarifications of mmio.data array meaning - the mmio.data array should hold bytes as they would appear in memory. Vgic is little endian device. And in case of BE image kernel side that emulates vgic, holds data in BE form. So we need to byteswap cpu<->le32 vgic registers when we read/write them from mmio.data[]. Change has no effect in LE case because cpu already runs in le32. Signed-off-by: Victor Kamensky <victor.kamensky@linaro.org> --- virt/kvm/arm/vgic.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)