Re: [PATCH v2 3/3] hw/arm/virt: allow creation of a second NonSecure UART

["Philippe Mathieu-Daudé" <philmd@linaro.org>]

On 10/6/24 18:23, Peter Maydell wrote:
> For some use-cases, it is helpful to have more than one UART
> available to the guest.  If the second UART slot is not already used
> for a TrustZone Secure-World-only UART, create it as a NonSecure UART
> only when the user provides a serial backend (e.g.  via a second
> -serial command line option).
> 
> This avoids problems where existing guest software only expects a
> single UART, and gets confused by the second UART in the DTB.  The
> major example of this is older EDK2 firmware, which will send the
> GRUB bootloader output to UART1 and the guest serial output to UART0.
> Users who want to use both UARTs with a guest setup including EDK2
> are advised to update to EDK2 release edk2-stable202311 or newer.
> (The prebuilt EDK2 blobs QEMU upstream provides are new enough.)
> The relevant EDK2 changes are the ones described here:
> https://bugzilla.tianocore.org/show_bug.cgi?id=4577
> 
> Inspired-by: Axel Heider <axel.heider@hensoldt.net>
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
> Tested-by: Laszlo Ersek <lersek@redhat.com>
> ---
>   docs/system/arm/virt.rst |  6 +++++-
>   include/hw/arm/virt.h    |  1 +
>   hw/arm/virt-acpi-build.c | 12 ++++++++----
>   hw/arm/virt.c            | 38 +++++++++++++++++++++++++++++++++++---
>   4 files changed, 49 insertions(+), 8 deletions(-)

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>