don't zero out ioreq page

ioreq page may contain some pending I/O requests, and we need to
handle the pending I/O req after migration.

TODO:
1. update qemu to handle the pending I/O req

Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Cc: Paul Durrant <paul.durrant@citrix.com>
blktap2: dynamic allocate aio_requests to avoid -EBUSY error

In normal case, there are at most TAPDISK_DATA_REQUESTS request
at the same time. But in remus mode, the write requests are
forwarded from the master side, and cached in block-remus. All
cached requests will be forwarded to aio driver when syncing
primary vm and backup vm. In this case, The number of requests
may be more than TAPDISK_DATA_REQUESTS. So aio driver can't hanlde
these requests at the same time, it will cause tapdisk2 exit.

We don't know how many requests will be handled, so dynamic allocate
aio_requests to avoid this error.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Jiang Yunhong <yunhong.jiang@intel.com>
Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Cc: Shriram Rajagopalan <rshriram@cs.ubc.ca>
block-remus: fix memory leak

Fix the following two memory leak:
1. If s->ramdisk.prev is not NULL, we merge the write requests in
   s->ramdisk.h into s->ramdisk.prev, and then destroy s->ramdisk.h.
   But we forget to free hash value when destroying s->ramdisk.h.
2. When write requests is finished, replicated_write_callback() will
   be called. We forget free the buff in this function.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Jiang Yunhong <yunhong.jiang@intel.com>
Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Cc: Shriram Rajagopalan <rshriram@cs.ubc.ca>
block-remus: pass uuid to the callback td_open

remus's callback td_open needs uuid, but it is hard coded as 0.
After commit 4b1af8, the vbd's uuid is the minor of the blktap
device, not 0.

Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Cc: Shriram Rajagopalan <rshriram@cs.ubc.ca>
blktap2: return the correct dev path

The user uses TAPDISK_MESSAGE_OPEN to pass the devpath to tapdisk2,
and will use TAPDISK_MESSAGE_LIST to query and get the pid of the
tapdisk2.

The devpath's format is: driver:params[|driver:params[...]].
The first vbd image only contains the first params, and we will
return driver:params, not devpath. The devpath is stored in
vbd->name, so return vbd->name instead of image->name.

Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Cc: Shriram Rajagopalan <rshriram@cs.ubc.ca>
block-remus: use correct way to get remus_image

We set remus_image in backup_read(). If we do flush
before the first read operation, remus_image will be
NULL. Pass image to remus via the callback td_open().

Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Cc: Shriram Rajagopalan <rshriram@cs.ubc.ca>
block-remus: fix bug in tdremus_close()

We close ctl_fd.fd, but we don't unregister ctl_fd.id. It will
cause select() return fails, and the user cannot talk with
tapdisk2.

This patch also does some cleanup.

Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Cc: Shriram Rajagopalan <rshriram@cs.ubc.ca>
blktap2: use correct way to get free event id

If we register/unregister event too many times, and we use event id
from 1 again. But we don't check it if it is used.

Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Cc: Shriram Rajagopalan <rshriram@cs.ubc.ca>
blktap2: don't return negative event id

If we find some error when registering a new event, we will return
a negative value. So we should skip negative event id.

Also fix a wrong check of return value.

Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Cc: Shriram Rajagopalan <rshriram@cs.ubc.ca>
blktap2: use correct way to define array.

Currently, we use the following way to define an array:
type array[] = {
    [index] = xxx,
    0,
};
So array[index+1] will be NULL. If index is not the last
index, it will override another index.

tapdisk_vbd_index is not defined, but array[DISK_TYPE_VINDEX]
is overridden, so we don't find this problem when building
the source.

Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Cc: Shriram Rajagopalan <rshriram@cs.ubc.ca>
don't call client_flush() when switching to unprotected mode

If we switch the mode from primary to unprotected, the connection
between primary and backup cannot be used.

Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Cc: Shriram Rajagopalan <rshriram@cs.ubc.ca>
pass correct file to qemu if we use blktap2

If we use blktap2, the correct file should be blktap device
not the pdev_path.

Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Cc: Shriram Rajagopalan <rshriram@cs.ubc.ca>
support blktap remus in xl

With this patch, we can use blktap remus like this:
disk = [ 'format=remus,devtype=disk,access=w,vdev=hda,backendtype=tap,target=192.168.3.1:9000|aio:filename' ]

Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Cc: Shriram Rajagopalan <rshriram@cs.ubc.ca>
update libxl__device_disk_from_xs_be() to support blktap device

If the disk backend is blktap device, we store "format:pdev_path"
in tapdisk-params, and store "phy" in type. So use tapdisk-params
to set libxl_device_disk instead of params and type.

Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Cc: Shriram Rajagopalan <rshriram@cs.ubc.ca>
x86/hvm: Always set pending event injection when loading VMC[BS] state.

In colo mode, secondary vm is running, so VM_ENTRY_INTR_INFO may
valid before restoring vmcs. If there is no pending event after
restoring vm, we should clear it.

Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>

Also clear pending software exceptions.
Copy the fix to SVM as well.

Signed-off-by: Tim Deegan <tim@xen.org>

Cc: Jun Nakajima <jun.nakajima@intel.com>
Cc: Kevin Tian <kevin.tian@intel.com>
Cc: Aravind Gopalakrishnan <Aravind.Gopalakrishnan@amd.com>
Cc: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>