Re: [PATCH v2 1/7] KVM: arm64: Fix missing RES1 in emulation of DBGBIDR

[Alexandru Elisei <alexandru.elisei@arm.com>]

Hi Marc,

The patch looks correct to me. Just to be on the safe side, I had a look at how
the other fields are generated and they match the architecture:

Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com>

On 1/25/21 12:26 PM, Marc Zyngier wrote:
> The AArch32 CP14 DBGDIDR has bit 15 set to RES1, which our current
> emulation doesn't set. Just add the missing bit.
>
> Reported-by: Peter Maydell <peter.maydell@linaro.org>
> Reviewed-by: Eric Auger <eric.auger@redhat.com>
> Signed-off-by: Marc Zyngier <maz@kernel.org>
> ---
>  arch/arm64/kvm/sys_regs.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
> index 3313dedfa505..0c0832472c4a 100644
> --- a/arch/arm64/kvm/sys_regs.c
> +++ b/arch/arm64/kvm/sys_regs.c
> @@ -1711,7 +1711,7 @@ static bool trap_dbgidr(struct kvm_vcpu *vcpu,
>  		p->regval = ((((dfr >> ID_AA64DFR0_WRPS_SHIFT) & 0xf) << 28) |
>  			     (((dfr >> ID_AA64DFR0_BRPS_SHIFT) & 0xf) << 24) |
>  			     (((dfr >> ID_AA64DFR0_CTX_CMPS_SHIFT) & 0xf) << 20)
> -			     | (6 << 16) | (el3 << 14) | (el3 << 12));
> +			     | (6 << 16) | (1 << 15) | (el3 << 14) | (el3 << 12));
>  		return true;
>  	}
>  }