Hi Andre,
On 15/11/16 14:27, Andre Przywara wrote:
> The GICv2 spec says in section 4.3.12 that a "CPU targets field bit that
> corresponds to an unimplemented CPU interface is RAZ/WI."
> Currently we allow the guest to write any value in there and it can
> read that back.
> Mask the written value with the proper CPU mask to be spec compliant.
>
> Signed-off-by: Andre Przywara <andre.przywara@xxxxxxx>
> ---
> virt/kvm/arm/vgic/vgic-mmio-v2.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/virt/kvm/arm/vgic/vgic-mmio-v2.c b/virt/kvm/arm/vgic/vgic-mmio-v2.c
> index b44b359..e59d4c7 100644
> --- a/virt/kvm/arm/vgic/vgic-mmio-v2.c
> +++ b/virt/kvm/arm/vgic/vgic-mmio-v2.c
> @@ -129,6 +129,7 @@ static void vgic_mmio_write_target(struct kvm_vcpu *vcpu,
> unsigned long val)
> {
> u32 intid = VGIC_ADDR_TO_INTID(addr, 8);
> + u8 cpu_mask = (1 << atomic_read(&vcpu->kvm->online_vcpus)) - 1;
For the sake of avoiding open-coding things, how about using GENMASK?
> int i;
>
> /* GICD_ITARGETSR[0-7] are read-only */
> @@ -141,7 +142,7 @@ static void vgic_mmio_write_target(struct kvm_vcpu *vcpu,
>
> spin_lock(&irq->irq_lock);
>
> - irq->targets = (val >> (i * 8)) & 0xff;
> + irq->targets = ((val >> (i * 8)) & 0xff) & cpu_mask;
Can't you just drop the '& 0xff' part, since cpu_mask is guaranteed to
be more restrictive?
> target = irq->targets ? __ffs(irq->targets) : 0;
> irq->target_vcpu = kvm_get_vcpu(vcpu->kvm, target);
>
>
Thanks,
M.
--
Jazz is not dead. It just smells funny...
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