On Tue, 2008-02-19 at 23:43 -0800, H. Peter Anvin wrote: > Ian Campbell wrote: > > On Mon, 2008-02-18 at 02:40 -0800, Joel Becker wrote: > >> On Sun, Feb 17, 2008 at 06:49:21PM +0000, Ian Campbell wrote: > > > >>> x86/xen: Do not scan for DMI unless the DMI region is reserved by e820. > > > >> This fixed it. I'm now booting successfully. Thank you! > > > > Excellent. Jeremy, are you happy for this to go in? > > > > NAK! > > It's pretty standard for 0xf0000...0x100000 to be marked RESERVED in > E820 on real hardware (including the system I'm typing on right now.) > It is so marked to indicate that hardware cannot be mapped into that > space. However, you can't rely on this fact -- heck, you can't rely on > E820 even existing on a real machine. I have specimens of real-life > machines that go both ways. > > This patch WILL break real hardware. > > What's particularly damning is that it's titled "x86/xen: Do not scan > for DMI unless the DMI region is reserved by e820." whereas in fact it > changes (breaks) generic code.
Sorry, I was trying to indicate that it was a generic change which was motivated by Xen support, but you're right it did look like I was saying it was a Xen only change. As far as the actual change goes I was assuming that any machine that has DMI/SMBIOS would easily be new enough to have an E820 which could be expected to reserve this region. Looks like I was mistaken about how long E820 had been around and/or how reliably it is used to reserve the tables. Anyway, will have to think of another solution. Ian. -- Ian Campbell Just because the message may never be received does not mean it is not worth sending. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
