Hi Christoffer, Peter, On 04/24/2018 06:50 PM, Peter Maydell wrote: > On 24 April 2018 at 17:46, Christoffer Dall <christoffer.dall@xxxxxxx> wrote: >> On Fri, Apr 13, 2018 at 10:20:48AM +0200, Eric Auger wrote: >>> --- a/Documentation/virtual/kvm/devices/arm-vgic-v3.txt >>> +++ b/Documentation/virtual/kvm/devices/arm-vgic-v3.txt >>> @@ -27,9 +27,32 @@ Groups: >>> VCPU and all of the redistributor pages are contiguous. >>> Only valid for KVM_DEV_TYPE_ARM_VGIC_V3. >>> This address needs to be 64K aligned. >>> + >>> + KVM_VGIC_V3_ADDR_TYPE_REDIST_REGION (rw, 64-bit) >>> + The attr field of kvm_device_attr encodes 3 values: >>> + bits: | 63 .... 52 | 51 .... 16 | 15 - 12 |11 - 0 >>> + values: | count | base | flags | index >>> + - index encodes the unique redistributor region index >> >> I'm not entirely sure I understand the purpose of the index field. >> Isn't a redistributor region identified uniquely by its base address? > > You need a way to tell the difference beween: > (1) redistributors for CPUs 0..63 at 0x40000000, redistributors > for 64..127 at 0x80000000 > (2) redistributors for CPUs 0..63 at 0x80000000, redistributors > for 64..127 at 0x40000000 > > The index field tells you which order the redistributor > regions go in. Yes redistributors are filled in the index order. This matches DT description (Documentation/devicetree/bindings/interrupt-controller/arm,gic-v3.txt): <0x0 0x2d000000 0 0x800000>, // GICR 1: CPUs 0-31 <0x0 0x2e000000 0 0x800000>; // GICR 2: CPUs 32-63 Thanks Eric > > thanks > -- PMM >
