Commit Graph

5517 Commits

Author SHA1 Message Date
Alan Cox
87c6fe2618 x86: update Alan Cox's email addresses
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-01-05 15:19:16 +01:00
Jiri Slaby
7aed55d108 x86: fix RIP printout in early_idt_handler
Impact: fix debug/crash printout

Since errorcode is popped out, RIP is on the top of the stack.
Use real RIP value instead of wrong CS.

Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Cc: <stable@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-01-04 10:20:29 +01:00
Markus Trippelsdorf
37dd3cb415 x86: remove debug printks (io_apic.c)
Impact: reduce printk noise

The message "alloc irq_2_pin on cpu 0 node 0" is printed way too often.

% dmesg|grep irq_2_pin|wc -l
20

Get rid of the debug printks.

Signed-off-by: Markus Trippelsdorf <markus@trippelsdorf.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-01-02 23:19:36 +01:00
Ingo Molnar
47dabdc7fc Merge branches 'x86/cleanups', 'x86/fpu' and 'x86/urgent' into x86/core 2009-01-02 22:41:52 +01:00
Ingo Molnar
923a789b49 Merge branch 'linus' into x86/cleanups
Conflicts:
	arch/x86/kernel/reboot.c
2009-01-02 22:41:36 +01:00
Linus Torvalds
b840d79631 Merge branch 'cpus4096-for-linus-2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'cpus4096-for-linus-2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (66 commits)
  x86: export vector_used_by_percpu_irq
  x86: use logical apicid in x2apic_cluster's x2apic_cpu_mask_to_apicid_and()
  sched: nominate preferred wakeup cpu, fix
  x86: fix lguest used_vectors breakage, -v2
  x86: fix warning in arch/x86/kernel/io_apic.c
  sched: fix warning in kernel/sched.c
  sched: move test_sd_parent() to an SMP section of sched.h
  sched: add SD_BALANCE_NEWIDLE at MC and CPU level for sched_mc>0
  sched: activate active load balancing in new idle cpus
  sched: bias task wakeups to preferred semi-idle packages
  sched: nominate preferred wakeup cpu
  sched: favour lower logical cpu number for sched_mc balance
  sched: framework for sched_mc/smt_power_savings=N
  sched: convert BALANCE_FOR_xx_POWER to inline functions
  x86: use possible_cpus=NUM to extend the possible cpus allowed
  x86: fix cpu_mask_to_apicid_and to include cpu_online_mask
  x86: update io_apic.c to the new cpumask code
  x86: Introduce topology_core_cpumask()/topology_thread_cpumask()
  x86: xen: use smp_call_function_many()
  x86: use work_on_cpu in x86/kernel/cpu/mcheck/mce_amd_64.c
  ...

Fixed up trivial conflict in kernel/time/tick-sched.c manually
2009-01-02 11:44:09 -08:00
Linus Torvalds
597b0d2162 Merge branch 'kvm-updates/2.6.29' of git://git.kernel.org/pub/scm/linux/kernel/git/avi/kvm
* 'kvm-updates/2.6.29' of git://git.kernel.org/pub/scm/linux/kernel/git/avi/kvm: (140 commits)
  KVM: MMU: handle large host sptes on invlpg/resync
  KVM: Add locking to virtual i8259 interrupt controller
  KVM: MMU: Don't treat a global pte as such if cr4.pge is cleared
  MAINTAINERS: Maintainership changes for kvm/ia64
  KVM: ia64: Fix kvm_arch_vcpu_ioctl_[gs]et_regs()
  KVM: x86: Rework user space NMI injection as KVM_CAP_USER_NMI
  KVM: VMX: Fix pending NMI-vs.-IRQ race for user space irqchip
  KVM: fix handling of ACK from shared guest IRQ
  KVM: MMU: check for present pdptr shadow page in walk_shadow
  KVM: Consolidate userspace memory capability reporting into common code
  KVM: Advertise the bug in memory region destruction as fixed
  KVM: use cpumask_var_t for cpus_hardware_enabled
  KVM: use modern cpumask primitives, no cpumask_t on stack
  KVM: Extract core of kvm_flush_remote_tlbs/kvm_reload_remote_mmus
  KVM: set owner of cpu and vm file operations
  anon_inodes: use fops->owner for module refcount
  x86: KVM guest: kvm_get_tsc_khz: return khz, not lpj
  KVM: MMU: prepopulate the shadow on invlpg
  KVM: MMU: skip global pgtables on sync due to cr3 switch
  KVM: MMU: collapse remote TLB flushes on root sync
  ...
2009-01-02 11:41:11 -08:00
Ingo Brueckl
e8e3232627 Fix compiler warning in arch/x86/mm/init_32.c
Signed-off-by: Ingo Brueckl <ib@wupperonline.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-02 10:27:32 -08:00
Jaswinder Singh Rajput
103ceffb95 x86: mpparse.c fix style problems
Impact: cleanup, fix style problems, more readable

Fixes style problems:

 WARNING: Use #include <linux/smp.h> instead of <asm/smp.h>
 WARNING: Use #include <linux/acpi.h> instead of <asm/acpi.h>
 WARNING: suspect code indent for conditional statements (8, 17)
 WARNING: space prohibited between function name and open parenthesis '('

total: 0 errors, 5 warnings

Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-01-02 19:24:28 +01:00
Jaswinder Singh Rajput
dceb4521c8 x86: nmi.c fix style problems
Impact: cleanup, fix style problems

Fixes style problems:

 WARNING: Use #include <linux/smp.h> instead of <asm/smp.h>
 WARNING: Use #include <linux/nmi.h> instead of <asm/nmi.h>

total: 0 errors, 2 warnings

Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-01-02 19:03:38 +01:00
Jaswinder Singh Rajput
423a54058f x86: ldt.c fix style problems
Impact: cleanup

Fixes style problems:

 WARNING: Use #include <linux/uaccess.h> instead of <asm/uaccess.h>
 ERROR: space required before the open parenthesis '('

total: 1 errors, 1 warnings

Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-01-02 17:46:24 +01:00
Jaswinder Singh Rajput
f634fa9411 x86: cpuid.c fix style problems
Impact: cleanup

Fixes style problems:

 WARNING: Use #include <linux/uaccess.h> instead of <asm/uaccess.h>
 ERROR: "foo * bar" should be "foo *bar"
 ERROR: trailing whitespace
 WARNING: usage of NR_CPUS is often wrong - consider using cpu_possible(), num_possible_cpus(), for_each_possible_cpu(), etc

total: 2 errors, 2 warnings

Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-01-02 17:46:23 +01:00
Cliff Wickman
46814dded1 x86, UV: remove erroneous BAU initialization
Impact: fix crash on x86/UV

UV is the SGI "UltraViolet" machine, which is x86_64 based.
BAU is the "Broadcast Assist Unit", used for TLB shootdown in UV.

This patch removes the allocation and initialization of an unused table.

This table is left over from a development test mode.  It is unused in
the present code.

And it was incorrectly initialized: 8 entries allocated but 17 initialized,
causing slab corruption.

This patch should go into 2.6.27 and 2.6.28 as well as the current tree.

Diffed against 2.6.28 (linux-next, 12/30/08)

Signed-off-by: Cliff Wickman <cpw@sgi.com>
Cc: <stable@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-01-02 17:26:25 +01:00
Ravikiran G Thirumalai
26799a6311 x86: fix incorrect __read_mostly on _boot_cpu_pda
The pda rework (commit 3461b0af02)
to remove static boot cpu pdas introduced a performance bug.

_boot_cpu_pda is the actual pda used by the boot cpu and is definitely
not "__read_mostly" and ended up polluting the read mostly section with
writes.  This bug caused regression of about 8-10% on certain syscall
intensive workloads.

Signed-off-by: Ravikiran Thirumalai <kiran@scalex86.org>
Acked-by: Mike Travis <travis@sgi.com>
Cc: <stable@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-01-02 17:16:29 +01:00
Ingo Brueckl
a9067d5376 x86: convert permanent_kmaps_init() from macro to inline
Impact: cleanup

This compiler warning:

  arch/x86/mm/init_32.c:515: warning: unused variable 'pgd_base'

triggers because permanent_kmaps_init() is a CPP macro in the
!CONFIG_HIGHMEM case, that does not tell the compiler that the
'pgd_base' parameter is used.

Convert permanent_kmaps_init() (and set_highmem_pages_init()) to
C inline functions - which gives the parameter a proper type and
which gets rid of the compiler warning as well.

Signed-off-by: Ingo Brueckl <ib@wupperonline.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-01-02 15:41:03 +01:00
Cyrill Gorcunov
c64d8996bd x86: early_printk - use sizeof instead of hardcoded number
Impact: cleanup

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-01-02 10:27:46 +01:00
Linus Torvalds
b58602a4ba Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6: (34 commits)
  nfsd race fixes: jfs
  nfsd race fixes: reiserfs
  nfsd race fixes: ext4
  nfsd race fixes: ext3
  nfsd race fixes: ext2
  nfsd/create race fixes, infrastructure
  filesystem notification: create fs/notify to contain all fs notification
  fs/block_dev.c: __read_mostly improvement and sb_is_blkdev_sb utilization
  kill ->dir_notify()
  filp_cachep can be static in fs/file_table.c
  fix f_count description in Documentation/filesystems/files.txt
  make INIT_FS use the __RW_LOCK_UNLOCKED initialization
  take init_fs to saner place
  kill vfs_permission
  pass a struct path * to may_open
  kill walk_init_root
  remove incorrect comment in inode_permission
  expand some comments (d_path / seq_path)
  correct wrong function name of d_put in kernel document and source comment
  fix switch_names() breakage in short-to-short case
  ...
2008-12-31 15:57:56 -08:00
Al Viro
18d8fda7c3 take init_fs to saner place
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-12-31 18:07:42 -05:00
Linus Torvalds
db200df0b3 Merge branch 'irq-fixes-for-linus-4' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'irq-fixes-for-linus-4' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  sparseirq: move __weak symbols into separate compilation unit
  sparseirq: work around __weak alias bug
  sparseirq: fix hang with !SPARSE_IRQ
  sparseirq: set lock_class for legacy irq when sparse_irq is selected
  sparseirq: work around compiler optimizing away __weak functions
  sparseirq: fix desc->lock init
  sparseirq: do not printk when migrating IRQ descriptors
  sparseirq: remove duplicated arch_early_irq_init()
  irq: simplify for_each_irq_desc() usage
  proc: remove ifdef CONFIG_SPARSE_IRQ from stat.c
  irq: for_each_irq_desc() move to irqnr.h
  hrtimer: remove #include <linux/irq.h>
2008-12-31 09:00:59 -08:00
Marcelo Tosatti
8791723920 KVM: MMU: handle large host sptes on invlpg/resync
The invlpg and sync walkers lack knowledge of large host sptes,
descending to non-existant pagetable level.

Stop at directory level in such case.

Fixes SMP Windows XP with hugepages.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2008-12-31 16:55:49 +02:00
Avi Kivity
3f353858c9 KVM: Add locking to virtual i8259 interrupt controller
While most accesses to the i8259 are with the kvm mutex taken, the call
to kvm_pic_read_irq() is not.  We can't easily take the kvm mutex there
since the function is called with interrupts disabled.

Fix by adding a spinlock to the virtual interrupt controller.  Since we
can't send an IPI under the spinlock (we also take the same spinlock in
an irq disabled context), we defer the IPI until the spinlock is released.
Similarly, we defer irq ack notifications until after spinlock release to
avoid lock recursion.

Signed-off-by: Avi Kivity <avi@redhat.com>
2008-12-31 16:55:48 +02:00
Avi Kivity
25e2343246 KVM: MMU: Don't treat a global pte as such if cr4.pge is cleared
The pte.g bit is meaningless if global pages are disabled; deferring
mmu page synchronization on these ptes will lead to the guest using stale
shadow ptes.

Fixes Vista x86 smp bootloader failure.

Signed-off-by: Avi Kivity <avi@redhat.com>
2008-12-31 16:55:48 +02:00
Jan Kiszka
4531220b71 KVM: x86: Rework user space NMI injection as KVM_CAP_USER_NMI
There is no point in doing the ready_for_nmi_injection/
request_nmi_window dance with user space. First, we don't do this for
in-kernel irqchip anyway, while the code path is the same as for user
space irqchip mode. And second, there is nothing to loose if a pending
NMI is overwritten by another one (in contrast to IRQs where we have to
save the number). Actually, there is even the risk of raising spurious
NMIs this way because the reason for the held-back NMI might already be
handled while processing the first one.

Therefore this patch creates a simplified user space NMI injection
interface, exporting it under KVM_CAP_USER_NMI and dropping the old
KVM_CAP_NMI capability. And this time we also take care to provide the
interface only on archs supporting NMIs via KVM (right now only x86).

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2008-12-31 16:55:47 +02:00
Jan Kiszka
264ff01d55 KVM: VMX: Fix pending NMI-vs.-IRQ race for user space irqchip
As with the kernel irqchip, don't allow an NMI to stomp over an already
injected IRQ; instead wait for the IRQ injection to be completed.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2008-12-31 16:55:47 +02:00
Marcelo Tosatti
eb64f1e8cd KVM: MMU: check for present pdptr shadow page in walk_shadow
walk_shadow assumes the caller verified validity of the pdptr pointer in
question, which is not the case for the invlpg handler.

Fixes oops during Solaris 10 install.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2008-12-31 16:55:46 +02:00
Avi Kivity
ca9edaee1a KVM: Consolidate userspace memory capability reporting into common code
Signed-off-by: Avi Kivity <avi@redhat.com>
2008-12-31 16:55:46 +02:00
Eduardo Habkost
e93353c93a x86: KVM guest: kvm_get_tsc_khz: return khz, not lpj
kvm_get_tsc_khz() currently returns the previously-calculated preset_lpj
value, but it is in loops-per-jiffy, not kHz. The current code works
correctly only when HZ=1000.

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2008-12-31 16:55:44 +02:00
Marcelo Tosatti
ad218f85e3 KVM: MMU: prepopulate the shadow on invlpg
If the guest executes invlpg, peek into the pagetable and attempt to
prepopulate the shadow entry.

Also stop dirty fault updates from interfering with the fork detector.

2% improvement on RHEL3/AIM7.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2008-12-31 16:55:44 +02:00
Marcelo Tosatti
6cffe8ca4a KVM: MMU: skip global pgtables on sync due to cr3 switch
Skip syncing global pages on cr3 switch (but not on cr4/cr0). This is
important for Linux 32-bit guests with PAE, where the kmap page is
marked as global.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2008-12-31 16:55:44 +02:00
Marcelo Tosatti
b1a368218a KVM: MMU: collapse remote TLB flushes on root sync
Collapse remote TLB flushes on root sync.

kernbench is 2.7% faster on 4-way guest. Improvements have been seen
with other loads such as AIM7.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2008-12-31 16:55:43 +02:00
Marcelo Tosatti
60c8aec6e2 KVM: MMU: use page array in unsync walk
Instead of invoking the handler directly collect pages into
an array so the caller can work with it.

Simplifies TLB flush collapsing.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2008-12-31 16:55:43 +02:00
Amit Shah
fbce554e94 KVM: x86 emulator: Fix handling of VMMCALL instruction
The VMMCALL instruction doesn't get recognised and isn't processed
by the emulator.

This is seen on an Intel host that tries to execute the VMMCALL
instruction after a guest live migrates from an AMD host.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2008-12-31 16:55:43 +02:00
Guillaume Thouvenin
9bf8ea42fe KVM: x86 emulator: add the emulation of shld and shrd instructions
Add emulation of shld and shrd instructions

Signed-off-by: Guillaume Thouvenin <guillaume.thouvenin@ext.bull.net>
Signed-off-by: Avi Kivity <avi@redhat.com>
2008-12-31 16:55:43 +02:00
Guillaume Thouvenin
d175226a5f KVM: x86 emulator: add the assembler code for three operands
Add the assembler code for instruction with three operands and one
operand is stored in ECX register

Signed-off-by: Guillaume Thouvenin <guillaume.thouvenin@ext.bull.net>
Signed-off-by: Avi Kivity <avi@redhat.com>
2008-12-31 16:55:42 +02:00
Guillaume Thouvenin
bfcadf83ec KVM: x86 emulator: add a new "implied 1" Src decode type
Add SrcOne operand type when we need to decode an implied '1' like with
regular shift instruction

Signed-off-by: Guillaume Thouvenin <guillaume.thouvenin@ext.bull.net>
Signed-off-by: Avi Kivity <avi@redhat.com>
2008-12-31 16:55:42 +02:00
Guillaume Thouvenin
0dc8d10f7d KVM: x86 emulator: add Src2 decode set
Instruction like shld has three operands, so we need to add a Src2
decode set. We start with Src2None, Src2CL, and Src2ImmByte, Src2One to
support shld/shrd and we will expand it later.

Signed-off-by: Guillaume Thouvenin <guillaume.thouvenin@ext.bull.net>
Signed-off-by: Avi Kivity <avi@redhat.com>
2008-12-31 16:55:42 +02:00
Guillaume Thouvenin
45ed60b371 KVM: x86 emulator: Extend the opcode descriptor
Extend the opcode descriptor to 32 bits. This is needed by the
introduction of a new Src2 operand type.

Signed-off-by: Guillaume Thouvenin <guillaume.thouvenin@ext.bull.net>
Signed-off-by: Avi Kivity <avi@redhat.com>
2008-12-31 16:55:41 +02:00
Hannes Eder
efff9e538f KVM: VMX: fix sparse warning
Impact: make global function static

  arch/x86/kvm/vmx.c:134:3: warning: symbol 'vmx_capability' was not declared. Should it be static?

Signed-off-by: Hannes Eder <hannes@hanneseder.net>
Signed-off-by: Avi Kivity <avi@redhat.com>
2008-12-31 16:55:06 +02:00
Avi Kivity
f3fd92fbdb KVM: Remove extraneous semicolon after do/while
Notices by Guillaume Thouvenin.

Signed-off-by: Avi Kivity <avi@redhat.com>
2008-12-31 16:55:05 +02:00
Avi Kivity
2b48cc75b2 KVM: x86 emulator: fix popf emulation
Set operand type and size to get correct writeback behavior.

Signed-off-by: Avi Kivity <avi@redhat.com>
2008-12-31 16:55:05 +02:00
Avi Kivity
cf5de4f886 KVM: x86 emulator: fix ret emulation
'ret' did not set the operand type or size for the destination, so
writeback ignored it.

Signed-off-by: Avi Kivity <avi@redhat.com>
2008-12-31 16:55:05 +02:00
Avi Kivity
8a09b6877f KVM: x86 emulator: switch 'pop reg' instruction to emulate_pop()
Signed-off-by: Avi Kivity <avi@redhat.com>
2008-12-31 16:55:04 +02:00
Avi Kivity
781d0edc5f KVM: x86 emulator: allow pop from mmio
Signed-off-by: Avi Kivity <avi@redhat.com>
2008-12-31 16:55:04 +02:00
Avi Kivity
faa5a3ae39 KVM: x86 emulator: Extract 'pop' sequence into a function
Switch 'pop r/m' instruction to use the new function.

Signed-off-by: Avi Kivity <avi@redhat.com>
2008-12-31 16:55:04 +02:00
Avi Kivity
6b7ad61ffb KVM: x86 emulator: consolidate emulation of two operand instructions
No need to repeat the same assembly block over and over.

Signed-off-by: Avi Kivity <avi@redhat.com>
2008-12-31 16:55:03 +02:00
Avi Kivity
dda96d8f1b KVM: x86 emulator: reduce duplication in one operand emulation thunks
Signed-off-by: Avi Kivity <avi@redhat.com>
2008-12-31 16:55:03 +02:00
Marcelo Tosatti
ecc5589f19 KVM: MMU: optimize set_spte for page sync
The write protect verification in set_spte is unnecessary for page sync.

Its guaranteed that, if the unsync spte was writable, the target page
does not have a write protected shadow (if it had, the spte would have
been write protected under mmu_lock by rmap_write_protect before).

Same reasoning applies to mark_page_dirty: the gfn has been marked as
dirty via the pagefault path.

The cost of hash table and memslot lookups are quite significant if the
workload is pagetable write intensive resulting in increased mmu_lock
contention.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2008-12-31 16:55:02 +02:00
Glauber Costa
423cd25a5a x86: KVM guest: sign kvmclock as paravirt
Currently, we only set the KVM paravirt signature in case
of CONFIG_KVM_GUEST. However, it is possible to have it turned
off, while CONFIG_KVM_CLOCK is turned on. This is also a paravirt
case, and should be shown accordingly.

Signed-off-by: Glauber Costa <glommer@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2008-12-31 16:55:00 +02:00
Avi Kivity
df203ec9a7 KVM: VMX: Conditionally request interrupt window after injecting irq
If we're injecting an interrupt, and another one is pending, request
an interrupt window notification so we don't have excess latency on the
second interrupt.

This shouldn't happen in practice since an EOI will be issued, giving a second
chance to request an interrupt window, but...

Signed-off-by: Avi Kivity <avi@redhat.com>
2008-12-31 16:55:00 +02:00
Eduardo Habkost
d176720d34 x86: disable VMX on all CPUs on reboot
On emergency_restart, we may need to use an NMI to disable virtualization
on all CPUs. We do that using nmi_shootdown_cpus() if VMX is enabled.

Note: With this patch, we will run the NMI stuff only when the CPU where
emergency_restart() was called has VMX enabled. This should work on most
cases because KVM enables VMX on all CPUs, but we may miss the small
window where KVM is doing that. Also, I don't know if all code using
VMX out there always enable VMX on all CPUs like KVM does. We have two
other alternatives for that:

a) Have an API that all code that enables VMX on any CPU should use
   to tell the kernel core that it is going to enable VMX on the CPUs.
b) Always call nmi_shootdown_cpus() if the CPU supports VMX. This is
   a bit intrusive and more risky, as it would run nmi_shootdown_cpus()
   on emergency_reboot() even on systems where virtualization is never
   enabled.

Finding a proper point to hook the nmi_shootdown_cpus() call isn't
trivial, as the non-emergency machine_restart() (that doesn't need the
NMI tricks) uses machine_emergency_restart() directly.

The solution to make this work without adding a new function or argument
to machine_ops was setting a 'reboot_emergency' flag that tells if
native_machine_emergency_restart() needs to do the virt cleanup or not.

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2008-12-31 16:54:58 +02:00