Re: [PATCH] wrong pa calculation fix (extboot)

[Anthony Liguori <aliguori@us.ibm.com>]

Nguyen Anh Quynh wrote:
> This patch fixes a wrong calculation in the physical address of
> extboot (qemu/hw/extboot.c). Looks like a typo.
>
> Signed-off-by: Nguyen Anh Quynh <aquynh@gmail.com>
>   
> diff --git a/qemu/hw/extboot.c b/qemu/hw/extboot.c
> index 056fb59..0dac34c 100644
> --- a/qemu/hw/extboot.c
> +++ b/qemu/hw/extboot.c
> @@ -81,7 +81,7 @@ static void extboot_write_cmd(void *opaque, uint32_t addr, uint32_t value)
>      get_translated_chs(bs, &cylinders, &heads, &sectors);
>  
>      if (cmd->type == 0x01 || cmd->type == 0x02) {
> -	target_ulong pa = cmd->xfer.segment * 16 + cmd->xfer.segment;
> +	target_ulong pa = cmd->xfer.segment * 16 + cmd->xfer.offset;
>  
>  	/* possible buffer overflow */
>  	if ((pa + cmd->xfer.nb_sectors * 512) > phys_ram_size)
>   

In practice, this check isn't actually necessary since a guest always 
has at least 1MB of memory.

Regards,

Anthony Liguori

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