On 02/23/2012 04:56 PM, Marc Zyngier wrote: > On 23/02/12 15:50, Alexander Graf wrote: >> On 02/23/2012 02:51 PM, Marc Zyngier wrote: >>> VMID is a 8bit field in VTTBR, and the top bits are better left alone. >>> >>> Signed-off-by: Marc Zyngier<marc.zyngier at arm.com> >>> --- >>> arch/arm/kvm/arm.c | 2 +- >>> 1 files changed, 1 insertions(+), 1 deletions(-) >>> >>> diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c >>> index 8dc723d..b402cd5 100644 >>> --- a/arch/arm/kvm/arm.c >>> +++ b/arch/arm/kvm/arm.c >>> @@ -361,7 +361,7 @@ static void update_vttbr(struct kvm *kvm) >>> pgd_phys = virt_to_phys(kvm->arch.pgd); >>> kvm->arch.vttbr = pgd_phys& ((1LLU<< 40) - 1) >>> & ~((2<< VTTBR_X) - 1); >>> - kvm->arch.vttbr |= kvm->arch.vmid<< 48; >>> + kvm->arch.vttbr |= (kvm->arch.vmid& VMID_MASK)<< 48; >> Why would vmid ever be> VMID_MASK? Shouldn't the setter do the mask >> already? > Because vmid = ((vmid_generation<< VMID_BITS) | hw_vmid). So by > definition, vmid is always> VMID_MASK, and we only want to program > hw_vmid into VTTBR. Ah, I see :o Alex
