No functional change.
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>
Message-id: 1466067800-25434-2-git-send-email-kraxel@redhat.com

It isn't unusual to happen, for example during reboot when the guest
doesn't reveice events for a while.  So better don't flood stderr
with alarming messages.  Turn them into tracepoints instead so they
can be enabled in case they are needed for trouble-shooting.
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>
Message-id: 1466675495-28797-1-git-send-email-kraxel@redhat.com

Keep track of button changes.  Send the extended 4-byte messages for
three button mice only in case we have something to report for the
middle button.  Use the short 3-byte messages (original protocol for
two-button microsoft mouse) otherwise.
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>
Message-id: 1467625375-31774-5-git-send-email-kraxel@redhat.com

Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>
Message-id: 1467625375-31774-4-git-send-email-kraxel@redhat.com

The msmouse chardev backend writes data without checking whenever there
is enough space.

That happens to work with linux guests, probably by pure luck because
the linux driver enables the fifo and the serial port emulation accepts
more data than announced via qemu_chr_be_can_write() in that case.

Handle this properly by adding a buffer to MouseState.  Hook up a
CharDriverState->accept_input() handler which feeds the buffer to the
serial port.  msmouse_event() only fills the buffer now, and calls the
accept_input handler too to kick off the transmission.
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>
Acked-by: NPaolo Bonzini <pbonzini@redhat.com>
Message-id: 1467625375-31774-3-git-send-email-kraxel@redhat.com

Add struct to track serial mouse state.  Store mouse event handler
there.  Unregister properly on chardev close.
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>
Acked-by: NPaolo Bonzini <pbonzini@redhat.com>
Message-id: 1467625375-31774-2-git-send-email-kraxel@redhat.com

Last round of s390x patches for 2.7:
- A large update of the s390x PCI code, bringing it in line with
  the architecture
- Fixes and improvements in the ipl (boot) code
- Refactoring in the css code

# gpg: Signature made Mon 11 Jul 2016 09:04:51 BST
# gpg:                using RSA key 0xDECF6B93C6F02FAF
# gpg: Good signature from "Cornelia Huck <huckc@linux.vnet.ibm.com>"
# gpg:                 aka "Cornelia Huck <cornelia.huck@de.ibm.com>"
# Primary key fingerprint: C3D0 D66D C362 4FF6 A8C0  18CE DECF 6B93 C6F0 2FAF

* remotes/cohuck/tags/s390x-20160711: (25 commits)
  s390x/pci: make hot-unplug handler smoother
  s390x/pci: replace fid with idx in msg data of msix
  s390x/pci: fix stpcifc_service_call
  s390x/pci: refactor list_pci
  s390x/pci: refactor s390_pci_find_dev_by_idx
  s390x/pci: add checkings in CLP_SET_PCI_FN
  s390x/pci: enable zpci hot-plug/hot-unplug
  s390x/pci: enable uid-checking
  s390x/pci: introduce S390PCIBusDevice qdev
  s390x/pci: introduce S390PCIIOMMU
  s390x/pci: introduce S390PCIBus
  s390x/pci: enforce zPCI state checking
  s390x/pci: refactor s390_pci_find_dev_by_fh
  s390x/pci: unify FH_ macros
  s390x/pci: write fid in CLP_QUERY_PCI_FN
  s390x/pci: acceleration for getting S390pciState
  s390x/pci: fix failures of dma map/unmap
  s390x/css: Unplug handler of virtual css bridge
  s390x/css: Factor out virtual css bridge and bus
  s390x/css: use define for "virtual-css-bridge" literal
  ...
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

two self-modifying code fixes

# gpg: Signature made Fri 08 Jul 2016 21:28:50 BST
# gpg:                using RSA key 0xAD1270CC4DD0279B
# gpg: Good signature from "Richard Henderson <rth7680@gmail.com>"
# gpg:                 aka "Richard Henderson <rth@redhat.com>"
# gpg:                 aka "Richard Henderson <rth@twiddle.net>"
# Primary key fingerprint: 9CB1 8DDA F8E8 49AD 2AFC  16A4 AD12 70CC 4DD0 279B

* remotes/rth/tags/pull-tcg-20160708:
  translate-all: Fix user-mode self-modifying code in 2 page long TB
  cputlb: Fix for self-modifying writes across page boundaries
  cputlb: Add address parameter to VICTIM_TLB_HIT
  cputlb: Move VICTIM_TLB_HIT out of line
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

x86 and machine queue, 2016-07-07

Highlights:
* Improvements on global property error handling
* Translate -cpu options to global properties
* LMCE support

# gpg: Signature made Thu 07 Jul 2016 20:59:01 BST
# gpg:                using RSA key 0x2807936F984DC5A6
# gpg: Good signature from "Eduardo Habkost <ehabkost@redhat.com>"
# Primary key fingerprint: 5A32 2FD5 ABC4 D3DB ACCF  D1AA 2807 936F 984D C5A6

* remotes/ehabkost/tags/x86-pull-request:
  target-i386: Enable LMCE for '-cpu host' if supported by host
  target-i386: Publish advised value of MSR_IA32_FEATURE_CONTROL via fw_cfg
  target-i386: kvm: Add basic Intel LMCE support
  target-i386: Report hyperv feature words through qom
  target-i386: Show host and VM TSC frequencies on mismatch
  pc: Parse CPU features only once
  arm: virt: Parse cpu_model only once
  cpu: Use CPUClass->parse_features() as convertor to global properties
  target-i386: Avoid using locals outside their scope
  target-i386: TCG can support CPUID.07H:EBX.erms
  target-sparc: Use sparc_cpu_parse_features() directly
  vl: Set errp to &error_abort on machine compat_props
  machine: Add machine_register_compat_props() function
  qdev: GlobalProperty.errp field
  qdev: Eliminate qemu_add_globals() function
  qdev: Don't stop applying globals on first error
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

build fix for travis

# gpg: Signature made Sun 10 Jul 2016 18:07:02 BST
# gpg:                using RSA key 0xAD1270CC4DD0279B
# gpg: Good signature from "Richard Henderson <rth7680@gmail.com>"
# gpg:                 aka "Richard Henderson <rth@redhat.com>"
# gpg:                 aka "Richard Henderson <rth@twiddle.net>"
# Primary key fingerprint: 9CB1 8DDA F8E8 49AD 2AFC  16A4 AD12 70CC 4DD0 279B

* remotes/rth/tags/pull-rth-20160710:
  build: Use $(AS) for optionrom explicitly
  linux-user: Fix i386 safe-syscall.S
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

Commit "9d8256eb virgl: pass whole GL scanout dimensions" missed the
opengl code path for gtk versions >= 3.16.  Update that one too and
fix the build with recent gtk versions.
Reported-by: NDr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>
Message-id: 1467876563-1351-1-git-send-email-kraxel@redhat.com
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

The current implementation of hot-unplug handler is abrupt. Any pci
operation will be just rejected if pci device is unconfigured. Thus a
pci device can not be reset or destroyed in a right, smooth and safe
way.

Improve this as follows:
- Notify the guest via a HP_EVENT_DECONFIGURE_REQUEST(0x303) event in
  the unplug handler, giving it a chance to deconfigure the device via
  sclp and allowing us to continue hot-unplug afterwards.
- Set up a timer that will generate the HP_EVENT_CONFIGURE_TO_STBRES
  (0x304) event as before if the guest did not react after an adequate
  time.
Signed-off-by: NYi Min Zhao <zyimin@linux.vnet.ibm.com>
Reviewed-by: NPierre Morel <pmorel@linux.vnet.ibm.com>
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>

Present code uses fid as the part of message data of msix for looking
up the specific zpci device. However it limits the usable range of fid,
and the code looking up the zpci device may fail due to truncation of
the fid.

In addition, fh is composed of enabled bit, FH_VIRT and the array index.
So we can use the array index as the identifier to store in msg data.
Signed-off-by: NYi Min Zhao <zyimin@linux.vnet.ibm.com>
Reviewed-by: NPierre Morel <pmorel@linux.vnet.ibm.com>
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>

Firstly the function misses dmaas checking. This patch adds it.

Secondly the function uses s390_pci_find_dev_by_fh() to look up the
zpci device. This may fail if the guest provides a valid and disabled
fh but fh of the associated zpci device is enabled. Thus we use
s390_pci_find_dev_by_idx() instead.
Signed-off-by: NYi Min Zhao <zyimin@linux.vnet.ibm.com>
Reviewed-by: NPierre Morel <pmorel@linux.vnet.ibm.com>
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>

Because of the refactor of s390_pci_find_dev_by_idx(), list_pci()
should be updated. We introduce a new function to get the next
available zpci device. It simplifies the code of looking up zpci
devices.
Signed-off-by: NYi Min Zhao <zyimin@linux.vnet.ibm.com>
Acked-by: NPierre Morel <pmorel@linux.vnet.ibm.com>
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>

s390_find_dev_by_idx() only indexes usable zpci devices. It implies
that the index value of each zpci device is dynamic and may change if
a new zpci device is plugged. So we have to use a constant index to
look up the device.
Signed-off-by: NYi Min Zhao <zyimin@linux.vnet.ibm.com>
Reviewed-by: NPierre Morel <pmorel@linux.vnet.ibm.com>
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>

The code in CLP_SET_PCI_FN case misses some checkings. Let's add
them.
Signed-off-by: NYi Min Zhao <zyimin@linux.vnet.ibm.com>
Reviewed-by: NPierre Morel <pmorel@linux.vnet.ibm.com>
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>

We need to support hot-plug/hot-unplug for the new zpci devices as
well. This patch enables the present hot-plug/hot-unplug handlers
to support not only generic pci devices but also zpci devices.
Signed-off-by: NYi Min Zhao <zyimin@linux.vnet.ibm.com>
Reviewed-by: NPierre Morel <pmorel@linux.vnet.ibm.com>
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>

The uid-checking facility guarantees uniqueness of the uid within the
vm and exposes the real uid to the guest when listing pci devices.
Let's always enable it and present it to the guest in the response to
the list pci clp command.
Signed-off-by: NYi Min Zhao <zyimin@linux.vnet.ibm.com>
Reviewed-by: NPierre Morel <pmorel@linux.vnet.ibm.com>
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>

To support definitions of s390 pci attributes in Qemu cmdline, we have
to make current S390PCIBusDevice struct inherit DeviceState and add
three properties for it. Currently we only support definitions of uid
and fid.

'uid' is optionally defined by users, identifies a zpci device and
must be defined with a 16-bit and non-zero unique value.

'fid' ranges from 0x0 to 0xFFFFFFFF. For fid property, we introduce a
new PropertyInfo by the name of s390_pci_fid_propinfo with our special
setter and getter. As 'fid' is optional, introduce 'fid_defined' to
track whether the user specified a fid.

'target' field is to direct qemu to find the corresponding generic PCI
device. It is equal to the 'id' value of one of generic pci devices.
If the user doesn't specify 'id' parameter for a generic pci device,
its 'id' value will be generated automatically and use this value as
'target' to create an associated zpci device.

If the user did not specify 'uid' or 'fid', values are generated
automatically. 'target' is required.

In addition, if a pci device has no associated zpci device, the code
will generate a zpci device automatically for it.
Signed-off-by: NYi Min Zhao <zyimin@linux.vnet.ibm.com>
Reviewed-by: NPierre Morel <pmorel@linux.vnet.ibm.com>
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>

Currently each zpci device holds its own DMA address space and memory
region. At the same time, all instances of zpci device are stored in
S390pciState. So duirng the initialization of S390pciState, all zpci
devices are created and then all DMA address spaces are created. Thus,
when initializing pci devices, their corresponding DMA address spaces
could be found.

But zpci qdev will be introduced later. Zpci device may be initialized
and plugged afterwards generic pci device. So we should initialize all
DMA address spaces and memory regions before initializing zpci devices.

We introduce a new struct named S390PCIIOMMU. And a new field of
S390pciState, which is an array to store all instances of S390PCIIOMMU,
is added so that qemu pci code could find the corresponding DMA
address space when initializing a generic pci device. And this should
be done before the connection of a zpci device and a generic pci
device is built.
Signed-off-by: NYi Min Zhao <zyimin@linux.vnet.ibm.com>
Acked-by: NPierre Morel <pmorel@linux.vnet.ibm.com>
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>

To enable S390PCIBusDevice as qdev, there should be a new bus to
plug and manage all instances of S390PCIBusDevice. Due to this,
S390PCIBus is introduced.
Signed-off-by: NYi Min Zhao <zyimin@linux.vnet.ibm.com>
Reviewed-by: NPierre Morel <pmorel@linux.vnet.ibm.com>
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>

Current code uses some fields combinatorially to indicate the state of
a s390 pci device. This patch introduces device states in order to make
the code more readable and more logical.
Signed-off-by: NYi Min Zhao <zyimin@linux.vnet.ibm.com>
Reviewed-by: NPierre Morel <pmorel@linux.vnet.ibm.com>
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>

Because this function is called very frequently, we should use a more
effective way to find the zpci device. So we use the FH's index to get
the device directly.
Signed-off-by: NYi Min Zhao <zyimin@linux.vnet.ibm.com>
Reviewed-by: NPierre Morel <pmorel@linux.vnet.ibm.com>
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>

Present code uses some macros to structure PCI Function Handle. But
their names don't have a uniform format. Let's use FH_MASK_ as the
unified prefix.

While we're at it, differentiate the SHM bits: use different bits for
vfio and emulated devices.
Signed-off-by: NYi Min Zhao <zyimin@linux.vnet.ibm.com>
Reviewed-by: NPierre Morel <pmorel@linux.vnet.ibm.com>
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>

We forgot to write the fid; fix that.
Signed-off-by: NYi Min Zhao <zyimin@linux.vnet.ibm.com>
Acked-by: NPierre Morel <pmorel@linux.vnet.ibm.com>
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>

There are a number of places where the code needs to get the instance
of S390pciState. It calls object_resolve_path() every time. This
wastes a lot of time and leads to low performance. Thus we add
s390_get_phb() to improve it.

Because we always have a phb, we remove all return checkings in the
callers and add an assert in s390_get_phb() to make sure that phb is
getted successfully.
Signed-off-by: NYi Min Zhao <zyimin@linux.vnet.ibm.com>
Reviewed-by: NPierre Morel <pmorel@linux.vnet.ibm.com>
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>

In commit d78c19b5, vfio code stores
the IOMMU's offset_within_address_space and adjusts the IOVA before
calling vfio_dma_map/vfio_dma_unmap. But s390_translate_iommu already
considers the base address of an IOMMU memory region.

Thus we use pal as the size and 0x0 as the base address to initialize
IOMMU memory subregion.
Signed-off-by: NYi Min Zhao <zyimin@linux.vnet.ibm.com>
Reviewed-by: NPierre Morel <pmorel@linux.vnet.ibm.com>
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>

The previous patch moved virtual css bridge and bus out from
virtio-ccw, but kept the direct reference of virtio-ccw specific
unplug function inside css-bridge.c.

To make the virtual css bus and bridge useful for non-virtio devices,
this introduces a common unplug function pointer "unplug" to call
specific virtio-ccw unplug parts. Thus, the tight coupling to
virtio-ccw can be removed.

This unplug pointer is a member of CCWDeviceClass, which is introduced
as an abstract device layer called "ccw-device". This layer is between
DeviceState and specific devices which are plugged in virtual css bus,
like virtio-ccw device. The specific unplug handlers should be assigned
to "unplug" during initialization.
Signed-off-by: NJing Liu <liujbjl@linux.vnet.ibm.com>
Reviewed-by: NSascha Silbe <silbe@linux.vnet.ibm.com>
Reviewed-by: NDong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
Reviewed-by: NYi Min Zhao <zyimin@linux.vnet.ibm.com>
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>

Currently, common base layers virtual css bridge and bus are
defined in hw/s390x/virtio-ccw.c(h). In order to support
multiple types of devices in the virtual channel subsystem,
especially non virtio-ccw, refactoring work needs to be done.

This work is just a pure code move without any functional change
except dropping an empty function virtual_css_bridge_init() and
virtio_ccw_busdev_unplug() changing. virtio_ccw_busdev_unplug()
is specific to virtio-ccw but gets referenced from the common
virtual css bridge code. To keep the functional changes to a
minimum we export this function from virtio-ccw.c and continue
to reference it inside virtual_css_bridge_class_init()
(now living in hw/s390x/css-bridge.c). A follow-up patch will
clean this up.
Signed-off-by: NJing Liu <liujbjl@linux.vnet.ibm.com>
Reviewed-by: NSascha Silbe <silbe@linux.vnet.ibm.com>
Reviewed-by: NDong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>

Introduce a TYPE_* define (like we already use for a couple of other
QOM types) for the name of the virtual CSS bridge QOM type instead of
sprinkling the same string literal over several source files.
Signed-off-by: NSascha Silbe <silbe@linux.vnet.ibm.com>
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>

A lot of what virtio_ccw_device_realize() does isn't specific to
virtio; it would apply to emulated CCW as well. Factor it out to make
it easier to implement emulated CCW devices later on.
Signed-off-by: NSascha Silbe <silbe@linux.vnet.ibm.com>
Reviewed-by: NDong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
Reviewed-by: NHalil Pasic <pasic@linux.vnet.ibm.com>
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>

When migrating from a different QEMU version, the start_address and
bios_start_address may differ. During migration these values are migrated
and overwrite the values that were detected by QEMU itself.

On a reboot, QEMU will reload its own BIOS, but use the migrated start
addresses, which does not work if the values differ.

Fix this by not relying on the migrated values anymore, but still
provide them during migration, so existing QEMUs continue to work.
Signed-off-by: NDavid Hildenbrand <dahi@linux.vnet.ibm.com>
Cc: qemu-stable@nongnu.org
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>

If bootindex is specified for a device, we need to IPL from
it. Currently it works for ccw devices, but not for SCSI. To be able to
IPL from the specific device, pc-bios needs to know its address.
For this reason we add special QEMU_SCSI IPL type into the IPLB
structure, that contains the scsi device address.

We enhance the ipl block with a currently qemu-only parameter block
that allows us to specify a concrete scsi device.
Signed-off-by: NAlexander Yarygin <yarygin@linux.vnet.ibm.com>
Reviewed-by: NEric Farman <farman@linux.vnet.ibm.com>
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>

Contains:
- pc-bios/s390-ccw: Pass selected SCSI device to IPL
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>

There is ,bootindex=%d argument to specify the lookup order of
boot devices.

If a bootindex assigned to the device, then IPL Parameter Info Block
is created for that device when it is IPLed from.

If it is a mere SCSI device (not FCP), then IPIB is created with a
special SCSI type and its fields are used to store SCSI address of the
device. This new ipl block is private to qemu for now.

If the device to IPL from is specified this way, then SCSI bus lookup
is bypassed and prescribed devices uses the address specified.
Signed-off-by: NEugene (jno) Dvurechenski <jno@linux.vnet.ibm.com>
Signed-off-by: NAlexander Yarygin <yarygin@linux.vnet.ibm.com>
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>

For clang before 3.5, -fno-integrated-as does not exist,
so the workaround in 5f6f0e27 fails to build.

Use clang's default assembler for linux-user/safe-syscall.S,
and explicitly change to use the system assembler for the
option roms.
Tested-by: NAlex Bennée <alex.bennee@linaro.org>
Reviewed-by: NAlex Bennée <alex.bennee@linaro.org>
Signed-off-by: NRichard Henderson <rth@twiddle.net>

In user-mode emulation Translation Block can consist of 2 guest pages.
In that case QEMU also mprotects 2 host pages that are dedicated for
guest memory, containing instructions. QEMU detects self-modifying code
with SEGFAULT signal processing.

In case if instruction in 1st page is modifying memory of 2nd
page (or vice versa) QEMU will mark 2nd page with PAGE_WRITE,
invalidate TB, generate new TB contatining 1 guest instruction and
exit to CPU loop. QEMU won't call mprotect, and new TB will cause
same SEGFAULT. Page will have both PAGE_WRITE_ORG and PAGE_WRITE
flags, so QEMU will handle the signal as guest binary problem,
and exit with guest SEGFAULT.

Solution is to do following: In case if current TB was invalidated
continue to invalidate TBs from remaining guest pages and mark pages
as PAGE_WRITE. After that disable host page protection with mprotect.
If current tb was invalidated longjmp to main loop. That is more
efficient, since we won't get SEGFAULT when executing new TB.
Reviewed-by: NSergey Fedorov <sergey.fedorov@linaro.org>
Signed-off-by: NStanislav Shmarov <snarpix@gmail.com>
Message-Id: <1467880392-1043630-1-git-send-email-snarpix@gmail.com>
Signed-off-by: NRichard Henderson <rth@twiddle.net>

As it currently stands, QEMU does not properly handle self-modifying code
when the write is unaligned and crosses a page boundary. The procedure
for handling a write to the current translation block is to write-protect
the current translation block, catch the write, split up the translation
block into the current instruction (which remains write-protected so that
the current instruction is not modified) and the remaining instructions
in the translation block, and then restore the CPU state to before the
write occurred so the write will be retried and successfully executed.
However, since unaligned writes across pages are split into one-byte
writes for simplicity, writes to the second page (which is not the
current TB) may succeed before a write to the current TB is attempted,
and since these writes are not invalidated before resuming state after
splitting the TB, these writes will be performed a second time, thus
corrupting the second page. Credit goes to Patrick Hulin for
discovering this.

In recent 64-bit versions of Windows running in emulated mode, this
results in either being very unstable (a BSOD after a couple minutes of
uptime), or being entirely unable to boot. Windows performs one or more
8-byte unaligned self-modifying writes (xors) which intersect the end
of the current TB and the beginning of the next TB, which runs into the
aforementioned issue. This commit fixes that issue by making the
unaligned write loop perform the writes in forwards order, instead of
reverse order. This way, QEMU immediately tries to write to the current
TB, and splits the TB before any write to the second page is executed.
The write then proceeds as intended. With this patch applied, I am able
to boot and use Windows 7 64-bit and Windows 10 64-bit in QEMU without
KVM.

Per Richard Henderson's input, this patch also ensures the second page
is in the TLB before executing the write loop, to ensure the second
page is mapped.

The original discussion of the issue is located at
http://lists.nongnu.org/archive/html/qemu-devel/2014-08/msg02161.html.
Signed-off-by: NSamuel Damashek <samuel.damashek@invincea.com>
Message-Id: <20160706182652.16190-1-samuel.damashek@invincea.com>
Signed-off-by: NRichard Henderson <rth@twiddle.net>

[rth: Split out from the original patch.]
Signed-off-by: NSamuel Damashek <samuel.damashek@invincea.com>
Message-Id: <20160706182652.16190-1-samuel.damashek@invincea.com>
Signed-off-by: NRichard Henderson <rth@twiddle.net>