yesterday I tried to reactivate my old 486 box and wanted to install a
current Linux with latest kernel on it. But it turned out that the
latest kernel does not boot because the machine crashes early in the
setup code.

After some debugging it turned out that the problem is the query_ist()
function. If this interrupt with that function is called the machine
simply locks up. It looks like a BIOS bug. Looking for a workaround for
this problem I wrote the attached patch. It checks for the CPUID
instruction and if it is not implemented it does not call the speedstep
BIOS function. As far as I know speedstep should be available since some
Pentium earliest.

Alan Cox observed that it's available since the Pentium II, so cpuid
levels 4 and 5 can be excluded altogether.

H. Peter Anvin cleaned up the code some more:

> Right in concept, but I dislike the implementation (duplication of the
> CPU detect code we already have).  Could you try this patch and see if
> it works for you?

which, with a small modification to fix a build error with it the
resulting kernel boots on my machine.
Signed-off-by: NJoerg Roedel <joro@8bytes.org>
Signed-off-by: N"H. Peter Anvin" <hpa@zytor.com>
Cc: <stable@kernel.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Commit 74768ed8 "page allocator: use no-panic variant of
alloc_bootmem() in alloc_large_system_hash()" introduced two new
_nopanic macros which are undefined for CONFIG_HAVE_ARCH_BOOTMEM_NODE.
Signed-off-by: NJohannes Weiner <hannes@saeurebad.de>
Acked-by: N"Jan Beulich" <jbeulich@novell.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Jeff Chua reported that booting a !bigsmp kernel on a 16-way box
hangs silently.

this is a long-standing issue, smp start AP cpu could check the
apic id >=8 etc before trying to start it.

achieve this by moving the def_to_bigsmp check later and skip the
apicid id > 8

[ mingo@elte.hu: clean up the message that is printed. ]
Reported-by: N"Jeff Chua" <jeff.chua.linux@gmail.com>
Signed-off-by: NYinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

 arch/x86/kernel/setup.c   |    6 ------
 arch/x86/kernel/smpboot.c |   10 ++++++++++
 2 files changed, 10 insertions(+), 6 deletions(-)

Cyrill Gorcunov observed:

> you turned it into early_param so now it's NULL injecting vulnerabled.
> Could you please add checking for NULL str param?

fix that.

Also, change the name of 'str' into 'arg', to make it more apparent
that this is an optional argument that can be NULL, not a string
parameter that is empty when unset.
Reported-by: NCyrill Gorcunov <gorcunov@gmail.com>
Signed-off-by: NRene Herman <rene.herman@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Fix function prototype in header file to match source code:

linux-next-20080807/arch/x86/kernel/efi_64.c:100:14: error: symbol 'efi_ioremap' redeclared with different type (originally declared at include2/asm/efi.h:89) - different address spaces
Signed-off-by: NRandy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Fix function declaration:

 linux-next-20080807/arch/x86/kernel/pci-calgary_64.c:1353:36: warning: non-ANSI function declaration of function 'get_tce_space_from_tar'
Signed-off-by: NRandy Dunlap <randy.dunlap@oracle.com>
Acked-by: NAcked-by: Muli Ben-Yehuda <muli@il.ibm.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Simon Horman reported that gcc-3.4.x crashes when compiling
pgd_prepopulate_pmd() when PREALLOCATED_PMDS == 0 and CONFIG_DEBUG_INFO
is enabled.

Adding an extra check for PREALLOCATED_PMDS == 0 [which is compiled out
by gcc] seems to avoid the problem.
Reported-by: NSimon Horman <horms@verge.net.au>
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Acked-by: NSimon Horman <horms@verge.net.au>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

On 32-bit, "apic" is a __setup() param meaning it is parsed rather
late in the game. Make it an early_param() for apic_printk() use
by arch/x86/kernel/mpparse.c.

On 64-bit, it already is an early_param().
Signed-off-by: NRene Herman <rene.herman@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

commit 11a62a05 turns some formerly
nopped debugging printks in arch/x86/kernel/mppparse.c into regular
ones. The one at the top of smp_scan_config() in particular also
prints on !CONFIG_SMP/CONFIG_X86_LOCAL_APIC kernels and UP machines
without anything resembling MP tables which makes their lowly UP
owners wonder...

Turn the former Dprintk()s into apic_printk()s instead meaning that
their printing is dependent on passing the apic=verbose (or =debug)
command line param.

On 32-bit, "apic" is a __setup() param which isn't early enough
for this code and therefore needs a followup changing it into an
early_param(). On 64-bit, it already is.
Signed-off-by: NRene Herman <rene.herman@gmail.com>
Cc: Andrew Morton <akpm@osdl.org>
Cc: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

As pointed out and tracked by Yinghai Lu <yhlu.kernel@gmail.com>:

 Dhaval Giani got:
 kernel BUG at arch/x86/kernel/io_apic_64.c:357!
 invalid opcode: 0000 [1] SMP
 CPU 24
 ...

his system (x3950) has 8 ioapic, irq > 256

This was caused by:

       commit 9b7dc567
       Author: Thomas Gleixner <tglx@linutronix.de>
       Date:   Fri May 2 20:10:09 2008 +0200

          x86: unify interrupt vector defines

          The interrupt vector defines are copied 4 times around with minimal
          differences. Move them all into asm-x86/irq_vectors.h

It appears that Thomas did not notice that x86_64 does something
completely different when he merge irq_vectors.h

We can solve this for 2.6.27 by simply reintroducing the old heuristic
for setting NR_IRQS on x86_64 to a usable value, which trivially removes
the regression.

Long term it would be nice to harmonize the handling of ioapic interrupts
of x86_32 and x86_64 so we don't have this kind of confusion.

Dhaval Giani <dhaval@linux.vnet.ibm.com> tested an earlier version of
this patch by YH which confirms simply increasing NR_IRQS fixes the
problem.
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
Acked-by: NYinghai Lu <yhlu.kernel@gmail.com>
Cc: Dhaval Giani <dhaval@linux.vnet.ibm.com>
Cc: Mike Travis <travis@sgi.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Having cpu_online_map change during assign_irq_vector can result
in some really nasty and weird things happening.  The one that
bit me last time was accessing non existent per cpu memory for non
existent cpus.

This locking was removed in a sloppy x86_64 and x86_32 merge patch.

Guys can we please try and avoid subtly breaking x86 when we are
merging files together?
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

The lowmem mapping table created by VMI need not depend on max_low_pfn
at all.  Instead we now create an extra large mapping which covers all
possible lowmem instead of the physical ram that is actually available.

This allows the vmi initialization to be done before max_low_pfn could
be computed. We also move the vmi_init code very early in the boot process
so that nobody accidentally breaks the fixmap dependancy.
Signed-off-by: NAlok N Kataria <akataria@vmware.com>
Acked-by: NZachary Amsden <zach@vmware.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

The fdiv detection code writes s32 integer into
the boot_cpu_data.fdiv_bug.
However, the boot_cpu_data.fdiv_bug is only char (s8)
field so the detection overwrites already set fields for
other bugs, e.g. the f00f bug field.

Use local s32 variable to receive result.

This is a partial fix to Bugzilla #9928  - fixes wrong
information about the f00f bug (tested) and probably
for coma bug (I have no cpu to test this).
Signed-off-by: NKrzysztof Helt <krzysztof.h1@wp.pl>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

This IOMMU helper function doesn't work for some architectures:

  http://marc.info/?l=linux-kernel&m=121699304403202&w=2

It also breaks POWER and SPARC builds:

  http://marc.info/?l=linux-kernel&m=121730388001890&w=2

Currently, only x86 IOMMUs use this so let's move it to x86 for
now.
Reported-by: NStephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

* git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus:
  lguest: turn Waker into a thread, not a process
  lguest: Enlarge virtio rings
  lguest: Use GSO/IFF_VNET_HDR extensions on tun/tap
  lguest: Remove 'network: no dma buffer!' warning
  lguest: Adaptive timeout
  lguest: Tell Guest net not to notify us on every packet xmit
  lguest: net block unneeded receive queue update notifications
  lguest: wrap last_avail accesses.
  lguest: use cpu capability accessors
  lguest: virtio-rng support
  lguest: Support assigning a MAC address
  lguest: Don't leak /dev/zero fd
  lguest: fix verbose printing of device features.
  lguest: fix switcher_page leak on unload
  lguest: Guest int3 fix
  lguest: set max_pfn_mapped, growl loudly at Yinghai Lu

* 'for-linus' of git://git.o-hand.com/linux-mfd:
  mfd: accept pure device as a parent, not only platform_device
  mfd: add platform_data to mfd_cell
  mfd: Coding style fixes
  mfd: Use to_platform_device instead of container_of

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes/pci-2.6: (21 commits)
  x86/PCI: use dev_printk when possible
  PCI: add D3 power state avoidance quirk
  PCI: fix bogus "'device' may be used uninitialized" warning in pci_slot
  PCI: add an option to allow ASPM enabled forcibly
  PCI: disable ASPM on pre-1.1 PCIe devices
  PCI: disable ASPM per ACPI FADT setting
  PCI MSI: Don't disable MSIs if the mask bit isn't supported
  PCI: handle 64-bit resources better on 32-bit machines
  PCI: rewrite PCI BAR reading code
  PCI: document pci_target_state
  PCI hotplug: fix typo in pcie hotplug output
  x86 gart: replace to_pages macro with iommu_num_pages
  x86, AMD IOMMU: replace to_pages macro with iommu_num_pages
  iommu: add iommu_num_pages helper function
  dma-coherent: add documentation to new interfaces
  Cris: convert to using generic dma-coherent mem allocator
  Sh: use generic per-device coherent dma allocator
  ARM: support generic per-device coherent dma mem
  Generic dma-coherent: fix DMA_MEMORY_EXCLUSIVE
  x86: use generic per-device dma coherent allocator
  ...

* git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi-rc-fixes-2.6:
  [SCSI] qla2xxx: fix msleep compile error

Alexey Dobriyan reported trouble with LTP with the new fast-gup code,
and Johannes Weiner debugged it to non-page-aligned addresses, where the
new get_user_pages_fast() code would do all the wrong things, including
just traversing past the end of the requested area due to 'addr' never
matching 'end' exactly.

This is not a pretty fix, and we may actually want to move the alignment
into generic code, leaving just the core code per-arch, but Alexey
verified that the vmsplice01 LTP test doesn't crash with this.
Reported-and-tested-by: NAlexey Dobriyan <adobriyan@gmail.com>
Debugged-by: NJohannes Weiner <hannes@saeurebad.de>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

lguest uses a Waker process to break it out of the kernel (ie.
actually running the guest) when file descriptor needs attention.

Changing this from a process to a thread somewhat simplifies things:
it can directly access the fd_set of things to watch.  More
importantly, it means that the Waker can see Guest memory correctly,
so /dev/vring file descriptors will work as anticipated (the
alternative is to actually mmap MAP_SHARED, but you can't do that with
/dev/zero).
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

With big packets, 128 entries is a little small.

Guest -> Host 1GB TCP:
Before: 8.43625 seconds xmit 95640 recv 198266 timeout 49771 usec 1252
After: 8.01099 seconds xmit 49200 recv 102263 timeout 26014 usec 2118
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

Guest -> Host 1GB TCP:
Before 20.1974 seconds xmit 214510 recv 5 timeout 214491 usec 278
After 8.43625 seconds xmit 95640 recv 198266 timeout 49771 usec 1252

Host -> Guest 1GB TCP:
Before: Seconds 9.98854 xmit 172166 recv 5344 timeout 172157 usec 251
After: Seconds 5.72803 xmit 244322 recv 9919 timeout 244302 usec 156
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

This warning can happen a lot under load, and it should be warnx not
warn anwyay.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

Since the correct timeout value varies, use a heuristic which adjusts
the timeout depending on how many packets we've seen.  This gives
slightly worse results, but doesn't need tweaking when GSO is
introduced.

500 usec	19.1887		xmit 561141 recv 1 timeout 559657
Dynamic (278)	20.1974		xmit 214510 recv 5 timeout 214491 usec 278
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

virtio_ring has the ability to suppress notifications.  This prevents
a guest exit for every packet, but we need to set a timer on packet
receipt to re-check if there were any remaining packets.

Here are the times for 1G TCP Guest->Host with different timeout
settings (it matters because the TCP window doesn't grow big enough to
fill the entire buffer):

Timeout value	Seconds		Xmit/Recv/Timeout
None (before)	25.3784		xmit 7750233 recv 1
2500 usec	62.5119		xmit 207020 recv 2 timeout 207020
1000 usec	34.5379		xmit 207003 recv 2 timeout 207003
750 usec	29.2305		xmit 207002 recv 1 timeout 207002
500 usec	19.1887		xmit 561141 recv 1 timeout 559657
250 usec	20.0465		xmit 214128 recv 2 timeout 214110
100 usec	19.2583		xmit 561621 recv 1 timeout 560153

(Note that these values are sensitive to the GSO patches which come
 later, and probably other traffic-related variables, so take with a
 large grain of salt).
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

Number of exits transmitting 10GB Guest->Host before:
	network xmit 7858610 recv 118136

After:
	network xmit 7750233 recv 1
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

To simplify the transition to when we publish indices in the ring
(and make shuffling my patch queue easier), wrap them in a lg_last_avail()
macro.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

To support my little make-x86-bitops-use-proper-typechecking projectlet.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrea Arcangeli <andrea@qumranet.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Acked-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

This is a simple patch to add support for the virtio "hardware random
generator" to lguest.  It gets about 1.2 MB/sec reading from /dev/hwrng
in the guest.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

If you've got a nice DHCP configuration which maps MAC
addresses to specific IP addresses, then you're going to
want to start your guest with one of those MAC addresses.

Also, in Fedora, we have persistent network interface naming
based on the MAC address, so with randomly assigned
addresses you're soon going to hit eth13. Who knows what
will happen then!

Allow assigning a MAC address to the network interface with
e.g.

  --tunnet=bridge:eth0:00:FF:95:6B:DA:3D

or:

  --tunnet=192.168.121.1:00:FF:95:6B:DA:3D

which is pretty unintelligable, but ...

(includes Rusty's minor rework)
Signed-off-by: NMark McLoughlin <markmc@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

Signed-off-by: NMark McLoughlin <markmc@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

%02x is more appropriate for bytes than %08x.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

map_switcher allocates the array, unmap_switcher has to free it
accordingly.
Signed-off-by: NJohannes Weiner <hannes@saeurebad.de>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

Ron Minnich noticed that guest userspace gets a GPF when it tries to int3:
we need to copy the privilege level from the guest-supplied IDT to the real
IDT.  int3 is the only common case where guest userspace expects to invoke
an interrupt, so that's the symptom of failing to do this.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

6af61a76 'x86: clean up max_pfn_mapped
usage - 32-bit' makes the following comment:

    XEN PV and lguest may need to assign max_pfn_mapped too.

But no CC.  Yinghai, wasting fellow developers' time is a VERY bad
habit.  If you do it again, I will hunt you down and try to extract
the three hours of my life I just lost :)
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Cc: Yinghai Lu <yhlu.kernel@gmail.com>

Signed-off-by: NDmitry Baryshkov <dbaryshkov@gmail.com>
Signed-off-by: NSamuel Ortiz <sameo@openedhand.com>

arch/x86/mm/pgtable.c: In function 'pgd_mop_up_pmds':
  arch/x86/mm/pgtable.c:194: warning: unused variable 'pmd'

Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The computed color value is never actually written to hardware
colormap register.
Signed-off-by: NManuel Lauss <mano@roarinelk.homelinux.net>
Cc: Nobuhiro Iwamatsu <iwamatsu.nobuhiro@renesas.com>
Cc: Munakata Hisao <munakata.hisao@renesas.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>