Re: [PATCH v3] target/arm: Use correct variable for setting 'max' cpu's MIDR_EL1

[Peter Maydell <peter.maydell@linaro.org>]

On Tue, 28 Apr 2020 at 18:26, Philippe Mathieu-Daudé <f4bug@amsat.org> wrote:
>
> MIDR_EL1 a 64-bit system register with the top 32-bit being RES0.
>
> This fixes when compiling with -Werror=conversion:
>
>   target/arm/cpu64.c: In function ‘aarch64_max_initfn’:
>   target/arm/cpu64.c:628:21: error: conversion from ‘uint64_t’ {aka ‘long unsigned int’} to ‘uint32_t’ {aka ‘unsigned int’} may change value [-Werror=conversion]
>     628 |         cpu->midr = t;
>         |                     ^
>
> Suggested-by: Laurent Desnogues <laurent.desnogues@gmail.com>
> Suggested-by: Peter Maydell <peter.maydell@linaro.org>
> Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>

Applied to target-arm.next, with the commit message fixed
up to match the patch contents:

    target/arm: Use uint64_t for midr field in CPU state struct

    MIDR_EL1 is a 64-bit system register with the top 32-bit being RES0.
    Represent it in QEMU's ARMCPU struct with a uint64_t, not a
    uint32_t.

    This fixes an error when compiling with -Werror=conversion
    because we were manipulating the register value using a
    local uint64_t variable:

      target/arm/cpu64.c: In function ‘aarch64_max_initfn’:
      target/arm/cpu64.c:628:21: error: conversion from ‘uint64_t’
{aka ‘long unsigned int’} to ‘uint32_t      ’ {aka ‘unsigned int’} may
change value [-Werror=conversion]
        628 |         cpu->midr = t;
            |                     ^

    and future-proofs us against a possible future architecture
    change using some of the top 32 bits.

thanks
-- PMM