Re: [Xen-devel] [PATCH v2] hvmloader: write extra memory in CMOS

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Tue, 2013-11-12 at 15:32 +0000, Wei Liu wrote:
> There's a conventional protocol for virt BIOSes such as Boches, Seabios and
> OVMF to have the size of extra memory above 4GB be written to certain
> locations (0x5b-0x5d) in CMOS. So update these locations as well.
> 
> Note that Seabios in Xen doesn't need this as it gets e820 directly from
> Xen. Rombios doesn't read this value.
> 
> Signed-off-by: Wei Liu <wei.liu2@xxxxxxxxxx>

Is this patch now obsolete given the hvmloader/ovmf integration work you
are doing?

> ---
>  tools/firmware/hvmloader/hvmloader.c |   17 +++++++++++++++++
>  1 file changed, 17 insertions(+)
> 
> diff --git a/tools/firmware/hvmloader/hvmloader.c 
> b/tools/firmware/hvmloader/hvmloader.c
> index 1cc8cf2..9f692fb 100644
> --- a/tools/firmware/hvmloader/hvmloader.c
> +++ b/tools/firmware/hvmloader/hvmloader.c
> @@ -146,6 +146,7 @@ static void init_hypercalls(void)
>  static void cmos_write_memory_size(void)
>  {
>      uint32_t base_mem = 640, ext_mem, alt_mem;
> +    uint64_t extra_mem = 0;
>  
>      alt_mem = ext_mem = hvm_info->low_mem_pgend << PAGE_SHIFT;
>      ext_mem = (ext_mem > 0x0100000) ? (ext_mem - 0x0100000) >> 10 : 0;
> @@ -153,6 +154,15 @@ static void cmos_write_memory_size(void)
>          ext_mem = 0xffff;
>      alt_mem = (alt_mem > 0x1000000) ? (alt_mem - 0x1000000) >> 16 : 0;
>  
> +    /* According to hvm_info:
> +     *  0x100000000 to page_to_phys(high_mem_pgend)-1:
> +     *   RAM above 4GB
> +     * extra_mem written to CMOS is represented as 64kb chunks
> +     */
> +    extra_mem = hvm_info->high_mem_pgend;
> +    extra_mem = (extra_mem > 0x100000) ?
> +        (((extra_mem - 0x100000) << PAGE_SHIFT) >> 16) : 0;
> +
>      /* All BIOSes: conventional memory (CMOS *always* reports 640kB). */
>      cmos_outb(0x15, (uint8_t)(base_mem >> 0));
>      cmos_outb(0x16, (uint8_t)(base_mem >> 8));
> @@ -166,6 +176,13 @@ static void cmos_write_memory_size(void)
>      /* Some BIOSes: alternative extended memory (64kB chunks above 16MB). */
>      cmos_outb(0x34, (uint8_t)( alt_mem >> 0));
>      cmos_outb(0x35, (uint8_t)( alt_mem >> 8));
> +
> +    /* Used by virt BIOSes such as Boches, Seabios, OVMF etc: extra
> +     * memory (64kB chunks above 4GB)
> +     */
> +    cmos_outb(0x5d, (uint8_t)( extra_mem >> 16));
> +    cmos_outb(0x5c, (uint8_t)( extra_mem >> 8));
> +    cmos_outb(0x5b, (uint8_t)( extra_mem >> 0));
>  }
>  
>  /*



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