KVM tries to run as much as possible with the guest msrs loaded instead of
host msrs, since switching msrs is very expensive.  It also tries to minimize
the number of msrs switched according to the guest mode; for example,
MSR_LSTAR is needed only by long mode guests.  This optimization is done by
setup_msrs().

However, we must not change which msrs are switched while we are running with
guest msr state:

 - switch to guest msr state
 - call setup_msrs(), removing some msrs from the list
 - switch to host msr state, leaving a few guest msrs loaded

An easy way to trigger this is to kexec an x86_64 linux guest.  Early during
setup, the guest will switch EFER to not include SCE.  KVM will stop saving
MSR_LSTAR, and on the next msr switch it will leave the guest LSTAR loaded.
The next host syscall will end up in a random location in the kernel.

Fix by reloading the host msrs before changing the msr list.
Signed-off-by: Avi Kivity <avi@qumranet.com>

For improved concurrency, the guest walk is performed concurrently with other
vcpus.  This means that we need to revalidate the guest ptes once we have
write-protected the guest page tables, at which point they can no longer be
modified.

The current code attempts to avoid this check if the shadow page table is not
new, on the assumption that if it has existed before, the guest could not have
modified the pte without the shadow lock.  However the assumption is incorrect,
as the racing vcpu could have modified the pte, then instantiated the shadow
page, before our vcpu regains control:

  vcpu0        vcpu1

  fault
  walk pte

               modify pte
               fault in same pagetable
               instantiate shadow page

  lookup shadow page
  conclude it is old
  instantiate spte based on stale guest pte

We could do something clever with generation counters, but a test run by
Marcelo suggests this is unnecessary and we can just do the revalidation
unconditionally.  The pte will be in the processor cache and the check can
be quite fast.
Signed-off-by: Avi Kivity <avi@qumranet.com>

Some Linux versions allow the timer interrupt to be processed by more than
one cpu, leading to hangs due to tsc instability.  Work around the issue
by only disaptching the interrupt to vcpu 0.

Problem analyzed (and patch tested) by Sheng Yang.
Signed-off-by: Avi Kivity <avi@qumranet.com>

If the local apic initial count is zero, don't start a an hrtimer with infinite
frequency, locking up the host.
Signed-off-by: Avi Kivity <avi@qumranet.com>

the cr3 variable is now inside the vcpu->arch structure.
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

alloc_apic_access_page() can sleep, while vmx_vcpu_setup is called
inside a non preemptable region. Move it after put_cpu().
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

While installing Windows XP 64 bit wants to access the DEBUGCTL and the last
branch record (LBR) MSRs. Don't allowing this in KVM causes the installation to
crash. This patch allow the access to these MSRs and fixes the issue.
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Markus Rechberger <markus.rechberger@amd.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

This patch replaces the mmap_sem lock for the memory slots with a new
kvm private lock, it is needed beacuse untill now there were cases where
kvm accesses user memory while holding the mmap semaphore.
Signed-off-by: Izik Eidus <izike@qumranet.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

Injecting an GP when accessing this MSR lets Windows crash when running some
stress test tools in KVM.  So this patch emulates access to this MSR.
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Markus Rechberger <markus.rechberger@amd.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

One of the use cases for the supported cpuid list is to create a "greatest
common denominator" of cpu capabilities in a server farm.  As such, it is
useful to be able to get the list without creating a virtual machine first.

Since the code does not depend on the vm in any way, all that is needed is
to move it to the device ioctl handler.  The capability identifier is also
changed so that binaries made against -rc1 will fail gracefully.
Signed-off-by: Avi Kivity <avi@qumranet.com>

Whilst working on getting a VM to initialize in to IA32e mode I found
this issue. set_cr0 relies on comparing the old cr0 to the new one to
work correctly.  Move the assignment below so the compare can work.
Signed-off-by: Paul Knowles <paul@transitive.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

Explicitly enable the NM intercept in svm_set_cr0 if we enable TS in the guest
copy of CR0 for lazy FPU switching. This fixes guest SMP with Linux under SVM.
Without that patch Linux deadlocks or panics right after trying to boot the
other CPUs.
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Markus Rechberger <markus.rechberger@amd.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

If the guest writes to cr0 and leaves the TS flag at 0 while vcpu->fpu_active
is also 0, the TS flag in the guest's cr0 gets lost. This leads to corrupt FPU
state an causes Windows Vista 64bit to crash very soon after boot.  This patch
fixes this bug.
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Markus Rechberger <markus.rechberger@amd.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ieee1394/linux1394-2.6:
  firewire: fix crash in automatic module unloading
  firewire: potentially invalid pointers used in fw_card_bm_work
  firewire: fw-sbp2: better fix for NULL pointer dereference in scsi_remove_device

"modprobe firewire-ohci; sleep .1; modprobe -r firewire-ohci" used to
result in crashes like this:

    BUG: unable to handle kernel paging request at ffffffff8807b455
    IP: [<ffffffff8807b455>]
    PGD 203067 PUD 207063 PMD 7c170067 PTE 0
    Oops: 0010 [1] PREEMPT SMP
    CPU 0
    Modules linked in: i915 drm cpufreq_ondemand acpi_cpufreq freq_table applesmc input_polldev led_class coretemp hwmon eeprom snd_seq_oss snd_seq_midi_event snd_seq snd_seq_device snd_pcm_oss snd_mixer_oss button thermal processor sg snd_hda_intel snd_pcm snd_timer snd snd_page_alloc sky2 i2c_i801 rtc [last unloaded: crc_itu_t]
    Pid: 9, comm: events/0 Not tainted 2.6.25-rc2 #3
    RIP: 0010:[<ffffffff8807b455>]  [<ffffffff8807b455>]
    RSP: 0018:ffff81007dcdde88  EFLAGS: 00010246
    RAX: ffff81007dc95040 RBX: ffff81007dee5390 RCX: 0000000000005e13
    RDX: 0000000000008c8b RSI: 0000000000000001 RDI: ffff81007dee5388
    RBP: ffff81007dc5eb40 R08: 0000000000000002 R09: ffffffff8022d05c
    R10: ffffffff8023b34c R11: ffffffff8041a353 R12: ffff81007dee5388
    R13: ffffffff8807b455 R14: ffffffff80593bc0 R15: 0000000000000000
    FS:  0000000000000000(0000) GS:ffffffff8055a000(0000) knlGS:0000000000000000
    CS:  0010 DS: 0018 ES: 0018 CR0: 000000008005003b
    CR2: ffffffff8807b455 CR3: 0000000000201000 CR4: 00000000000006e0
    DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
    DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
    Process events/0 (pid: 9, threadinfo ffff81007dcdc000, task ffff81007dc95040)
    Stack:  ffffffff8023b396 ffffffff88082524 0000000000000000 ffffffff8807d9ae
    ffff81007dc5eb40 ffff81007dc9dce0 ffff81007dc5eb40 ffff81007dc5eb80
    ffff81007dc9dce0 ffffffffffffffff ffffffff8023be87 0000000000000000
    Call Trace:
    [<ffffffff8023b396>] ? run_workqueue+0xdf/0x1df
    [<ffffffff8023be87>] ? worker_thread+0xd8/0xe3
    [<ffffffff8023e917>] ? autoremove_wake_function+0x0/0x2e
    [<ffffffff8023bdaf>] ? worker_thread+0x0/0xe3
    [<ffffffff8023e813>] ? kthread+0x47/0x74
    [<ffffffff804198e0>] ? trace_hardirqs_on_thunk+0x35/0x3a
    [<ffffffff8020c008>] ? child_rip+0xa/0x12
    [<ffffffff8020b6e3>] ? restore_args+0x0/0x3d
    [<ffffffff8023e68a>] ? kthreadd+0x14c/0x171
    [<ffffffff8023e68a>] ? kthreadd+0x14c/0x171
    [<ffffffff8023e7cc>] ? kthread+0x0/0x74
    [<ffffffff8020bffe>] ? child_rip+0x0/0x12

    Code:  Bad RIP value.
    RIP  [<ffffffff8807b455>]
    RSP <ffff81007dcdde88>
    CR2: ffffffff8807b455
    ---[ end trace c7366c6657fe5bed ]---

Note that this crash happened _after_ firewire-core was unloaded.  The
shared workqueue tried to run firewire-core's device initialization jobs
or similar jobs.

The fix makes sure that firewire-ohci and hence firewire-core is not
unloaded before all device shutdown jobs have been completed.  This is
determined by the count of device initializations minus device releases.

Also skip useless retries in the node initialization job if the node is
to be shut down.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: Jarod Wilson <jwilson@redhat.com>

The bus management workqueue job was in danger to dereference NULL
pointers.  Also, after having temporarily lifted card->lock, a few node
pointers and a device pointer may have become invalid.

Add NULL pointer checks and get the necessary references.  Also, move
card->local_node out of fw_card_bm_work's sight during shutdown of the
card.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: Jarod Wilson <jwilson@redhat.com>

Patch "firewire: fw-sbp2: fix NULL pointer deref. in scsi_remove_device"
had the unintended effect that firewire-sbp2 could not be unloaded
anymore until all SBP-2 devices were unplugged.

We now fix the NULL pointer bug by reacquiring a reference to the sdev
instead of holding a reference to the sdev (and to the module) all the
time.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Tested-by: Jarod Wilson <jwilson@redhat.com>

Hi,

While we are looking at the printk issue, I see that its printk'ing the EOE
(end of event) records which is really not something that we need in syslog.
Its really intended for the realtime audit event stream handled by the audit
daemon. So, lets avoid printk'ing that record type.
Signed-off-by: Steve Grubb <sgrubb@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

On the latest kernels if one was to load about 15 rules, set the failure
state to panic, and then run service auditd stop the kernel will panic.
This is because auditd stops, then the script deletes all of the rules.
These deletions are sent as audit messages out of the printk kernel
interface which is already known to be lossy.  These will overun the
default kernel rate limiting (10 really fast messages) and will call
audit_panic().  The same effect can happen if a slew of avc's come
through while auditd is stopped.

This can be fixed a number of ways but this patch fixes the problem by
just not panicing if auditd is not running.  We know printk is lossy and
if the user chooses to set the failure mode to panic and tries to use
printk we can't make any promises no matter how hard we try, so why try?
At least in this way we continue to get lost message accounting and will
eventually know that things went bad.

The other change is to add a new call to audit_log_lost() if auditd
disappears.  We already pulled the skb off the queue and couldn't send
it so that message is lost.  At least this way we will account for the
last message and panic if the machine is configured to panic.  This code
path should only be run if auditd dies for unforeseen reasons.  If
auditd closes correctly audit_pid will get set to 0 and we won't walk
this code path.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Fix the following compiler warning by using "%zu" as defined in C99.

  CC      kernel/auditsc.o
  kernel/auditsc.c: In function 'audit_log_single_execve_arg':
  kernel/auditsc.c:1074: warning: format '%ld' expects type 'long int', but
  argument 4 has type 'size_t'
Signed-off-by: Paul Moore <paul.moore@hp.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

* 'upstream-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jgarzik/libata-dev:
  [libata] wrap kmap_atomic(KM_IRQ0) with local_irq_save/restore()
  sata_svw: Add support for HT1100 SATA controller

Interrupts must be disabled if using kmap_atomic(KM_IRQ0), but that was
not the case in a few code paths coming directly from ATA driver
interrupt handlers (which use spin_lock rather than spin_lock_irqsave).
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

* 'for-linus' of master.kernel.org:/home/rmk/linux-2.6-arm:
  [ARM] 4843/1: Add GCR_CLKBPB for PXA3xx
  [ARM] 4842/1: pxa: remove redundant IRQ saving/restoring in clk_pxa3xx_cken_*
  [ARM] 4841/1: pxa: fix typo in LCD platform data definition code for zylonite
  [ARM] 4840/1: pxa: fix the typo in get_irqnr_and_base
  [ARM] 4839/1: fixes kernel Oops in /dev/mem device driver for memory map with PHYS_OFF
  [ARM] eliminate MODULE_PARM() usage
  [ARM] 4838/1: Fix kexec for SA1100 machines
  [ARM] 4837/1: make __get_unaligned_*() return unsigned types
  [ARM] 4836/1: Make ATAGS_PROC depend on KEXEC

The PXA3xx AC97 controller has an additional control bit GCR_CLKBPB
which must be used during cold reset.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: eric miao <eric.miao@marvell.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

This is unnecessary since it is already protected by
spin_lock_irq{save, restore} in clock.c.
Signed-off-by: eric miao <eric.miao@marvell.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Signed-off-by: eric miao <eric.miao@marvell.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

This typo causes the incorrect calculation of the IRQ numbers
in the ICIP2 registers.
Signed-off-by: eric miao <eric.miao@marvell.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

"cat /dev/mem" may cause kernel Oops for boards with PHYS_OFFSET != 0
because character device is mapped to addresses starting from zero
and there is no protection against such situation.
Patch just add this.
Signed-off-by: Alexandre Rusev <arusev@ru.mvista.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Convert debug-only (and removed) MODULE_PARM() to module_param().
Compiles cleanly (with DEBUG=1).
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

This patch sets KEXEC_CONTROL_MEMORY_LIMIT to (-1)UL. As the value is
compared with physical addresses TASK_SIZE makes no sense. Machines
where the RAM addresses start above TASK_SIZE kexecs eats all memory
and crashes the kernel without this patch.
Signed-off-by: Thomas Kunze <thommycheck@gmx.de>
Acked-by: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Eric Sandeen tracked an XFS on ARM corruption bug down to a function
under fs/xfs/ involving some get_unaligned() calls on u64 pointers.
As it turns out, calling ARM's get_unaligned() on a u64 pointer
pointing to the following byte sequence:

	80 81 82 83 84 85 86 87

would return ffffffff83828180 (LE mode.)  This turns out to be
because of implicit u8 -> int promotion in ARM's implementation of
various helpers for get_unaligned(), causing them to accidentally
return signed instead of unsigned values, which in turn caused the
subsequent casts to unsigned long long in __get_unaligned_8_[bl]e()
to sign-extend the lower words.

Fix by casting the return values of __get_unaligned_[24]_[bl]e()
to unsigned int.

Cc: Eric Sandeen <sandeen@sandeen.net>
Cc: Rabeeh Khoury <rabeeh@marvell.com>
Cc: Nicolas Pitre <nico@marvell.com>
Signed-off-by: Lennert Buytenhek <buytenh@marvell.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

On Wed, Feb 20, 2008 at 11:50:33AM +0100, Guennadi Liakhovetski wrote:
> arch/arm/kernel/atags.c uses for some reason the
> KEXEC_BOOT_PARAMS_SIZE macro, which is only defined if CONFIG_KEXEC
> is set. So, either this macro should be defined always, or another
> macro should be used, or ATAGS_PROC should depend on KEXEC.

As the procfs export of ATAGS is not meant as a stable, general purpose
ABI it shouldn't be an independent, general configuration option.

This patch make ATAGS_PROC depend on KEXEC
Signed-off-by: Uli Luckas <u.luckas@road.de>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

This patch fixes a potentially invalid access to a per-CPU variable in
rcu_process_callbacks().

This per-CPU access needs to be done in such a way as to guarantee that
the code using it cannot move to some other CPU before all uses of the
value accessed have completed.  Even though this code is currently only
invoked from softirq context, which currrently cannot migrate to some
other CPU, life would be better if this code did not silently make such
an assumption.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

This fixes a oops encountered when doing hibernate/resume in presence of
PREEMPT_RCU.

The problem was that the code failed to disable preemption when
accessing a per-CPU variable.  This is OK when called from code that
already has preemption disabled, but such is not the case from the
suspend/resume code path.
Reported-by: Dave Young <hidave.darkstar@gmail.com>
Tested-by: Dave Young <hidave.darkstar@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

* git://git.kernel.org/pub/scm/linux/kernel/git/mingo/linux-2.6-sched:
  softlockup: fix task state setting
  rcu: add support for dynamic ticks and preempt rcu

Fix 32-on-64 pvops kernel:

we don't want userspace using syscall/sysenter, even if the hypervisor
supports it, so mask it out from CPUID.
Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

The 2.6.25 ptrace_bts_config structure in asm-x86/ptrace-abi.h
is defined with u32 types:

   #include <asm/types.h>

   /* configuration/status structure used in PTRACE_BTS_CONFIG and
      PTRACE_BTS_STATUS commands.
   */
   struct ptrace_bts_config {
           /* requested or actual size of BTS buffer in bytes */
           u32 size;
           /* bitmask of below flags */
           u32 flags;
           /* buffer overflow signal */
           u32 signal;
           /* actual size of bts_struct in bytes */
           u32 bts_size;
   };
   #endif

But u32 is only accessible in asm-x86/types.h if __KERNEL__,
leading to compile errors when ptrace.h is included from
user-space. The double-underscore versions that are exported
to user-space in asm-x86/types.h should be used instead.
Signed-off-by: Dave Anderson <anderson@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

revert the BTS ptrace extension for now.

based on general objections from Roland McGrath:

    http://lkml.org/lkml/2008/2/21/323

we'll let the BTS functionality cook some more and re-enable
it in v2.6.26. We'll leave the dead code around to help the
development of this code.

(X86_BTS is not defined at the moment)
Signed-off-by: Ingo Molnar <mingo@elte.hu>

avoid over-eager large page splitup.

When the target area needs to be split or is split already (ioremap)
then the current code enforces the split of large mappings in the alias
regions even if we could avoid it.

Use a separate variable processed in the cpa_data structure to carry
the number of pages which have been processed instead of reusing the
numpages variable. This keeps numpages intact and gives the alias code
a chance to keep large mappings intact.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

delay the removal of this symbol export by one more kernel release,
giving external modules such as VirtualBox a chance to stop using it.
Signed-off-by: Ingo Molnar <mingo@elte.hu>