Re: [Qemu-devel] [PATCH 3/3] target/arm: Implement DBGVCR32_EL2 system register

["Edgar E. Iglesias" <edgar.iglesias@gmail.com>]

On Tue, Jan 10, 2017 at 06:44:09PM +0000, Peter Maydell wrote:
> The DBGVCR_EL2 system register is needed to run a 32-bit
> EL1 guest under a Linux EL2 64-bit hypervisor. Its only
> purpose is to provide AArch64 with access to the state of
> the DBGVCR AArch32 register. Since we only have a dummy
> DBGVCR, implement a corresponding dummy DBGVCR32_EL2.
> 
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

Reviewed-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>


> ---
>  target/arm/helper.c | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/target/arm/helper.c b/target/arm/helper.c
> index dc90986..bda562d 100644
> --- a/target/arm/helper.c
> +++ b/target/arm/helper.c
> @@ -4066,6 +4066,13 @@ static const ARMCPRegInfo debug_cp_reginfo[] = {
>        .cp = 14, .opc1 = 0, .crn = 0, .crm = 7, .opc2 = 0,
>        .access = PL1_RW, .accessfn = access_tda,
>        .type = ARM_CP_NOP },
> +    /* Dummy DBGVCR32_EL2 (which is only for a 64-bit hypervisor
> +     * to save and restore a 32-bit guest's DBGVCR)
> +     */
> +    { .name = "DBGVCR32_EL2", .state = ARM_CP_STATE_AA64,
> +      .opc0 = 2, .opc1 = 4, .crn = 0, .crm = 7, .opc2 = 0,
> +      .access = PL2_RW, .accessfn = access_tda,
> +      .type = ARM_CP_NOP },
>      /* Dummy MDCCINT_EL1, since we don't implement the Debug Communications
>       * Channel but Linux may try to access this register. The 32-bit
>       * alias is DBGDCCINT.
> -- 
> 2.7.4
>