xen/p2m: Move code around to allow for better re-usage.

We are going to be using the early_alloc_p2m (and
early_alloc_p2m_middle) code in follow up patches which
are not related to setting identity pages.

Hence lets move the code out in its own function and
rename them as appropiate.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
xen/p2m: Allow alloc_p2m_middle to call reserve_brk depending on argument

For identity cases we want to call reserve_brk only on the boundary
conditions of the middle P2M (so P2M[x][y][0] = extend_brk). This is
to work around identify regions (PCI spaces, gaps in E820) which are not
aligned on 2MB regions.

However for the case were we want to allocate P2M middle leafs at the
early bootup stage, irregardless of this alignment check we need some
means of doing that.  For that we provide the new argument.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
xen/p2m: Collapse early_alloc_p2m_middle redundant checks.

At the start of the function we were checking for idx != 0
and bailing out. And later calling extend_brk if idx != 0.

That is unnecessary so remove that checks.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
xen/p2m: An early bootup variant of set_phys_to_machine

During early bootup we can't use alloc_page, so to allocate
leaf pages in the P2M we need to use extend_brk. For that
we are utilizing the early_alloc_p2m and early_alloc_p2m_middle
functions to do the job for us. This function follows the
same logic as set_phys_to_machine.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
KVM: x86: expose Intel cpu new features (HLE, RTM) to guest

Intel recently release 2 new features, HLE and RTM.
Refer to http://software.intel.com/file/41417.
This patch expose them to guest.

Signed-off-by: Liu, Jinsong <jinsong.liu@intel.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
KVM: resize kvm_io_range array dynamically

This patch makes the kvm_io_range array can be resized dynamically.

Signed-off-by: Amos Kong <akong@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
KVM: set upper bounds for iobus dev to limit userspace

kvm_io_bus devices are used for ioevent, pit, pic, ioapic,
coalesced_mmio.

Currently Qemu only emulates one PCI bus, it contains 32 slots,
one slot contains 8 functions, maximum of supported PCI devices:
 1 * 32 * 8 = 256. One virtio-blk takes one iobus device,
one virtio-net(vhost=on) takes two iobus devices.
The maximum of coalesced mmio zone is 100, each zone
has an iobus devices. So 300 io_bus devices are not enough.

Set an upper bounds for kvm_io_range to limit userspace.
1000 is a very large limit and not bloat the typical user.

Signed-off-by: Amos Kong <akong@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
KVM: SVM: count all irq windows exit

Also count the exits of fast-path.

Signed-off-by: Jason Wang <jasowang@redhat.com>
Acked-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
KVM: schedule debugfs statistics for removal

Deprecated in favour of tracepoints.

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
KVM: Factor out kvm_vcpu_kick to arch-generic code

The kvm_vcpu_kick function performs roughly the same funcitonality on
most all architectures, so we shouldn't have separate copies.

PowerPC keeps a pointer to interchanging waitqueues on the vcpu_arch
structure and to accomodate this special need a
__KVM_HAVE_ARCH_VCPU_GET_WQ define and accompanying function
kvm_arch_vcpu_wq have been defined. For all other architectures this
is a generic inline that just returns &vcpu->wq;

Acked-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Christoffer Dall <c.dall@virtualopensystems.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
KVM: PPC: Rework wqp conditional code

On PowerPC, we sometimes use a waitqueue per core, not per thread,
so we can't always use the vcpu internal waitqueue.

This code has been generalized by Christoffer Dall recently, but
unfortunately broke compilation for PowerPC. At the time the helper
function is defined, struct kvm_vcpu is not declared yet, so we can't
dereference it.

This patch moves all logic into the generic inline function, at which
time we have all information necessary.

Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
x86: pvclock: Add flag to indicate that a vm was stopped by the host

This flag will be used to check if the vm was stopped by the host when a soft
lockup was detected.  The host will set the flag when it stops the guest.  On
resume, the guest will check this flag if a soft lockup is detected and skip
issuing the warning.

Signed-off-by: Eric B Munson <emunson@mgebm.net>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
kvmclock: Add functions to check if the host has stopped the vm

When a host stops or suspends a VM it will set a flag to show this.  The
watchdog will use these functions to determine if a softlockup is real, or the
result of a suspended VM.

Signed-off-by: Eric B Munson <emunson@mgebm.net>
asm-generic changes Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
KVM: x86: Add ioctl for KVM_KVMCLOCK_CTRL

Now that we have a flag that will tell the guest it was suspended, create an
interface for that communication using a KVM ioctl.

Signed-off-by: Eric B Munson <emunson@mgebm.net>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
watchdog: add check for suspended vm in softlockup detector

A suspended VM can cause spurious soft lockup warnings.  To avoid these, the
watchdog now checks if the kernel knows it was stopped by the host and skips
the warning if so.  When the watchdog is reset successfully, clear the guest
paused flag.

Signed-off-by: Eric B Munson <emunson@mgebm.net>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
KVM: fix kvm_vcpu_kick build failure on S390

S390's kvm_vcpu_stat does not contain halt_wakeup member.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
kvmclock: remove unneeded EXPORT macro

check_and_clear_guest_paused does not need to be exported as it isn't used
by any modules, remove the export.

Signed-off-by: Eric B Munson <emunson@mgebm.net>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
KVM: MMU: Split the main body of rmap_write_protect() off from others

We will use this in the following patch to implement another function
which needs to write protect pages using the rmap information.

Note that there is a small change in debug printing for large pages:
we do not differentiate them from others to avoid duplicating code.

Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Signed-off-by: Avi Kivity <avi@redhat.com>
KVM: Avoid checking huge page mappings in get_dirty_log()

Dropped such mappings when we enabled dirty logging and we will never
create new ones until we stop the logging.

For this we introduce a new function which can be used to write protect
a range of PT level pages: although we do not need to care about a range
of pages at this point, the following patch will need this feature to
optimize the write protection of many pages.

Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Signed-off-by: Avi Kivity <avi@redhat.com>
KVM: Switch to srcu-less get_dirty_log()

We have seen some problems of the current implementation of
get_dirty_log() which uses synchronize_srcu_expedited() for updating
dirty bitmaps; e.g. it is noticeable that this sometimes gives us ms
order of latency when we use VGA displays.

Furthermore the recent discussion on the following thread
    "srcu: Implement call_srcu()"
    http://lkml.org/lkml/2012/1/31/211
also motivated us to implement get_dirty_log() without SRCU.

This patch achieves this goal without sacrificing the performance of
both VGA and live migration: in practice the new code is much faster
than the old one unless we have too many dirty pages.

Implementation:

The key part of the implementation is the use of xchg() operation for
clearing dirty bits atomically.  Since this allows us to update only
BITS_PER_LONG pages at once, we need to iterate over the dirty bitmap
until every dirty bit is cleared again for the next call.

Although some people may worry about the problem of using the atomic
memory instruction many times to the concurrently accessible bitmap,
it is usually accessed with mmu_lock held and we rarely see concurrent
accesses: so what we need to care about is the pure xchg() overheads.

Another point to note is that we do not use for_each_set_bit() to check
which ones in each BITS_PER_LONG pages are actually dirty.  Instead we
simply use __ffs() in a loop.  This is much faster than repeatedly call
find_next_bit().

Performance:

The dirty-log-perf unit test showed nice improvements, some times faster
than before, except for some extreme cases; for such cases the speed of
getting dirty page information is much faster than we process it in the
userspace.

For real workloads, both VGA and live migration, we have observed pure
improvements: when the guest was reading a file during live migration,
we originally saw a few ms of latency, but with the new method the
latency was less than 200us.

Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Signed-off-by: Avi Kivity <avi@redhat.com>