Re: [Qemu-devel] [PATCH 3/5] target/arm: Introduce read_sys_reg32 for kvm32

[Peter Maydell]

On 24 October 2018 at 12:37, Richard Henderson
<address@hidden> wrote:
> Assert that the value to be written is the correct size.
> No change in functionality here, just mirroring the same
> function from kvm64.
>
> Signed-off-by: Richard Henderson <address@hidden>
> ---
>  target/arm/kvm32.c | 41 ++++++++++++++++-------------------------
>  1 file changed, 16 insertions(+), 25 deletions(-)

> -    struct kvm_one_reg idregs[] = {
> -        {
> -            .id = KVM_REG_ARM | KVM_REG_SIZE_U32
> -            | ENCODE_CP_REG(15, 0, 0, 0, 0, 0, 0),
> -            .addr = (uintptr_t)&midr,
> -        },
> -        {
> -            .id = KVM_REG_ARM | KVM_REG_SIZE_U32
> -            | ENCODE_CP_REG(15, 0, 0, 0, 1, 0, 0),
> -            .addr = (uintptr_t)&id_pfr0,
> -        },
> -        {
> -            .id = KVM_REG_ARM | KVM_REG_SIZE_U32
> -            | KVM_REG_ARM_VFP | KVM_REG_ARM_VFP_MVFR1,
> -            .addr = (uintptr_t)&mvfr1,
> -        },
> -    };
>
>      if (!kvm_arm_create_scratch_host_vcpu(cpus_to_try, fdarray, &init)) {
>          return false;
> @@ -77,16 +69,15 @@ bool kvm_arm_get_host_cpu_features(ARMHostCPUFeatures 
> *ahcf)
>       */
>      ahcf->dtb_compatible = "arm,arm-v7";
>
> -    for (i = 0; i < ARRAY_SIZE(idregs); i++) {
> -        ret = ioctl(fdarray[2], KVM_GET_ONE_REG, &idregs[i]);
> -        if (ret) {
> -            break;
> -        }
> -    }
> +    err |= read_sys_reg32(fdarray[2], &midr, ARM_CP15_REG32(0, 0, 0, 0));
> +    err |= read_sys_reg32(fdarray[2], &id_pfr0, ARM_CP15_REG32(0, 0, 1, 0));


Reviewed-by: Peter Maydell <address@hidden>
with the declaration of 'i' removed.

(Confusingly, ENCODE_CP_REG and ARM_CP15_REG32 take the
op1/crn/crm/op2 arguments in different orders.)

thanks
-- PMM