[U-Boot] [PATCH 03/12] x86: doc: Mention qemu-x86_64 support

[Heinrich Schuchardt]

On 10/13/2018 05:06 PM, Bin Meng wrote:
> Currently only 32-bit U-Boot for QEMU x86 is documented. Mention
> the 64-bit support.
> 
> Signed-off-by: Bin Meng <bmeng.cn at gmail.com>
> 
> ---
> Changes in this version:
> - add more information about 64-bit support
> 
>  doc/README.x86 | 19 +++++++++++++++++--
>  1 file changed, 17 insertions(+), 2 deletions(-)
> 
> diff --git a/doc/README.x86 b/doc/README.x86
> index 8cc4672..64da4ac 100644
> --- a/doc/README.x86
> +++ b/doc/README.x86
> @@ -32,7 +32,7 @@ are supported:
>     - Link (Chromebook Pixel)
>     - Minnowboard MAX
>     - Samus (Chromebook Pixel 2015)
> -   - QEMU x86
> +   - QEMU x86 (32-bit & 64-bit)
>  
>  As for loading an OS, U-Boot supports directly booting a 32-bit or 64-bit
>  Linux kernel as part of a FIT image. It also supports a compressed zImage.
> @@ -376,7 +376,9 @@ QEMU x86 target instructions for bare mode:
>  
>  To build u-boot.rom for QEMU x86 targets, just simply run
>  
> -$ make qemu-x86_defconfig
> +$ make qemu-x86_defconfig (for 32-bit)
> +or
> +$ make qemu-x86_64_defconfig (for 64-bit)
>  $ make all
>  
>  Note this default configuration will build a U-Boot for the QEMU x86 i440FX
> @@ -479,6 +481,19 @@ Here the kernel (bzImage) is loaded to 01000000 and initrd is to 04000000. Then,
>  
>  => zboot 01000000 - 04000000 1b1ab50
>  
> +To run 64-bit U-Boot, qemu-system-x86_64 should be used instead, e.g.:
> +$ qemu-system-x86_64 -nographic -bios path/to/u-boot.rom
> +
> +Specific CPU can be specified via the '-cpu' parameter but please make

A specfic CPU ...

> +sure the specified CPU supports 64-bit like '-cpu core2duo'. Conversely
> +'-cpu pentium' won't work for obvious reasons that the processor only
> +supports 32-bit.
> +
> +Note 64-bit support is very preliminary at this point. Lots of features
> +are missing in the 64-bit world. One notable feature is VGA console

... is the VGA console ...

> +support which is currently missing, so that you must specify '-nographic'
> +to get 64-bit U-Boot up and running.
> +
>  Updating U-Boot on Edison
>  -------------------------
>  By default Intel Edison boards are shipped with preinstalled heavily
> 

Reviewed-by: Heinrich Schuchardt <xypron.glpk at gmx.de>