From: Keir Fraser <keir.xen@gmail.com>
To: Jan Beulich <JBeulich@suse.com>, xen-devel <xen-devel@lists.xen.org>
Subject: Re: [PATCH] x86/EDD: check MBR for BIOS magic before considering signature valid
Date: Wed, 30 May 2012 17:48:00 +0100 [thread overview]
Message-ID: <CBEC0DD0.3487C%keir.xen@gmail.com> (raw)
In-Reply-To: <4FC65A930200007800086F39@nat28.tlf.novell.com>
On 30/05/2012 16:36, "Jan Beulich" <JBeulich@suse.com> wrote:
> Signed-off-by: Jan Beulich <JBeulich@suse.com>
Acked-by: Keir Fraser <keir@xen.org>
> --- a/xen/arch/x86/boot/edd.S
> +++ b/xen/arch/x86/boot/edd.S
> @@ -53,12 +53,16 @@ edd_mbr_sig_read:
> jc edd_mbr_sig_done # on failure, we're done.
> cmpb $0, %ah # some BIOSes do not set CF
> jne edd_mbr_sig_done # on failure, we're done.
> + cmpw $0xaa55, bootsym(boot_edd_info)+0x1fe
> + jne .Ledd_mbr_sig_next
> movl bootsym(boot_edd_info)+EDD_MBR_SIG_OFFSET,%eax
> movb %dl, (%bx) # store BIOS drive number
> movl %eax, 4(%bx) # store signature from MBR
> incb bootsym(boot_mbr_signature_nr) # note that we stored
> something
> - incb %dl # increment to next device
> addw $8, %bx # increment sig buffer ptr
> +.Ledd_mbr_sig_next:
> + incb %dl # increment to next device
> + jz edd_mbr_sig_done
> cmpb $EDD_MBR_SIG_MAX,bootsym(boot_mbr_signature_nr)
> jb edd_mbr_sig_read
> edd_mbr_sig_done:
>
>
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xen.org
> http://lists.xen.org/xen-devel
prev parent reply other threads:[~2012-05-30 16:48 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-05-30 15:36 [PATCH] x86/EDD: check MBR for BIOS magic before considering signature valid Jan Beulich
2012-05-30 16:48 ` Keir Fraser [this message]
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