Re: [XEN v3 04/12] xen/Arm: vGICv3: Adapt emulation of GICR_TYPER for AArch32

[Julien Grall <julien@xxxxxxx>]

Hi Ayan,

On 11/11/2022 14:17, Ayan Kumar Halder wrote:
> Refer ARM DDI 0487I.a ID081822, G8-9650, G8.2.113
> Aff3 does not exist on AArch32.
> Also, refer ARM DDI 0406C.d ID040418, B4-1644, B4.1.106
> Aff3 does not exist on Armv7 (ie arm32).
>
> Thus, access to aff3 have been contained within "#ifdef CONFIG_ARM_64".
> Also, v->arch.vmpidr is a 32 bit register on AArch32. So, we have copied it to
> 'uint64_t vmpidr' to perform the shifts.
>
> Signed-off-by: Ayan Kumar Halder <ayan.kumar.halder@xxxxxxx>
> ---
>
> Changes from :-
> v1 - Assigned v->arch.vmpidr to "uint64_t vmpdir". Then, we can use
> MPIDR_AFFINITY_LEVEL macros to extract the affinity value.
>
> v2 - 1. "MPIDR_AFFINITY_LEVEL(vmpidr, 3)" is contained within
> "#ifdef CONFIG_ARM_64".
> 2. Updated commit message.
>
>   xen/arch/arm/vgic-v3.c | 12 ++++++++----
>   1 file changed, 8 insertions(+), 4 deletions(-)
>
> diff --git a/xen/arch/arm/vgic-v3.c b/xen/arch/arm/vgic-v3.c
> index 3f4509dcd3..a7a935ff57 100644
> --- a/xen/arch/arm/vgic-v3.c
> +++ b/xen/arch/arm/vgic-v3.c
> @@ -191,12 +191,16 @@ static int __vgic_v3_rdistr_rd_mmio_read(struct vcpu *v, 
> mmio_info_t *info,
>       case VREG64(GICR_TYPER):
>       {
>           uint64_t typer, aff;
> +        uint64_t vmpidr = v->arch.vmpidr;
The type-widening here deserve an in-code comment. Otherwise, it would 
be easier for someone to decide to open-code v->arch.vmpidr again.
>   
>           if ( !vgic_reg64_check_access(dabt) ) goto bad_width;
> -        aff = (MPIDR_AFFINITY_LEVEL(v->arch.vmpidr, 3) << 56 |
> -               MPIDR_AFFINITY_LEVEL(v->arch.vmpidr, 2) << 48 |
> -               MPIDR_AFFINITY_LEVEL(v->arch.vmpidr, 1) << 40 |
> -               MPIDR_AFFINITY_LEVEL(v->arch.vmpidr, 0) << 32);
> +        aff = (
> +#ifdef CONFIG_ARM_64
> +               MPIDR_AFFINITY_LEVEL(vmpidr, 3) << 56 |
> +#endif
> +               MPIDR_AFFINITY_LEVEL(vmpidr, 2) << 48 |
> +               MPIDR_AFFINITY_LEVEL(vmpidr, 1) << 40 |
> +               MPIDR_AFFINITY_LEVEL(vmpidr, 0) << 32);
>           typer = aff;
>           /* We use the VCPU ID as the redistributor ID in bits[23:8] */
>           typer |= v->vcpu_id << GICR_TYPER_PROC_NUM_SHIFT;
Cheers,

--
Julien Grall