When the toolstack modifies memory of a running ARM VM it may happen
that the underlying memory of a current vCPU PC is changed. Without
flushing the icache the vCPU may continue executing stale instructions.
Also expose the xc_domain_cacheflush through xenctrl.h.
Signed-off-by: Tamas K Lengyel <tamas.lengyel@zentific.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
The fail3 error path skips the va_end() call, which typically leaks memory for
64bit x86 code.
Introduced by c/s 524a98c2ac, spotted by Coverity.
Coverity-ID: 1399608
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Leaves 8000000b-18 are reserved. Leaf 80000019 is 1G TLB information and leaf
0x8000001a is performance hints. These leaves have previously been hidden
from guests, but are perfectly safe to expose when appicable.
Update libxc to also expose these leaves.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
With accurate vendor information available, the shared bits can be sorted out
during recalculation, rather than at query time in the legacy cpuid path.
This means that:
* Duplication can be dropped from the automatically generated cpuid data.
* The toolstack need not worry about setting them appropriately.
* They can be dropped from the system maximum featuresets.
While editing gen-cpuid.py, reflow some comments which exceeded the expected
line length.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Doug Goldstein <cardoe@cardoe.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
NOTE: This patch also modifies the types of the 'vector', 'type' and
'insn_len' arguments of xc_hvm_inject_trap() from uint32_t to
uint8_t. In practice the values passed were always truncated to
8 bits.
Suggested-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Acked-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
This patch removes the need for handling HVMOP restarts, so that
infrastructure is removed.
NOTE: This patch also modifies the type of the 'nr' argument of
xc_hvm_set_mem_type() from uint64_t to uint32_t. In practice the
value passed was always truncated to 32 bits.
Suggested-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Acked-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
This patch introduces code to handle DMOP continuations.
NOTE: This patch also modifies the type of the 'nr' argument of
xc_hvm_modified_memory() from uint64_t to uint32_t. In practice the
value passed was always truncated to 32 bits.
Suggested-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Acked-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
... HVMOP_set_pci_link_route
These HVMOPs were exposed to guests so their definitions need to be
preserved for compatibility. This patch therefore updates
__XEN_LATEST_INTERFACE_VERSION__ to 0x00040900 and makes the HVMOP
defintions conditional on __XEN_INTERFACE_VERSION__ less than that value.
NOTE: This patch also widens the 'domain' parameter of
xc_hvm_set_pci_intx_level() from a uint8_t to a uint16_t.
Suggested-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Acked-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
The handle type passed to the underlying shadow and hap functions is
changed for compatibility with the new hypercall buffer.
NOTE: This patch also modifies the type of the 'nr' parameter of
xc_hvm_track_dirty_vram() from uint64_t to uint32_t. In practice
the value passed was always truncated to 32 bits.
Suggested-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Acked-by: George Dunlap <george.dunlap@eu.citrix.com>
Acked-by: Tim Deegan <tim@xen.org>
Acked-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
...as a set of hypercalls to be used by a device model.
As stated in the new docs/designs/dm_op.markdown:
"The aim of DMOP is to prevent a compromised device model from
compromising domains other then the one it is associated with. (And is
therefore likely already compromised)."
See that file for further information.
This patch simply adds the boilerplate for the hypercall.
Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
Suggested-by: Ian Jackson <ian.jackson@citrix.com>
Suggested-by: Jennifer Herbert <jennifer.herbert@citrix.com>
Acked-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
libxc performs a lot of calculations for the xstate leaf when generating a
guests cpuid policy. To correctly construct a policy for an HVM guest, this
logic depends on native cpuid leaking through from real hardware.
In particular, the logic is potentially wrong for an HVM-based toolstack
domain (e.g. PVH dom0), and definitely wrong if cpuid faulting is applied to a
PV domain.
Xen now performs all the necessary calculations, using native values. The
only piece of information the toolstack need worry about is single xstate
feature leaf.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
The tools that use kexec are asynchronous in nature and do not keep
state changes. As such provide an hypercall to find out whether an
image has been loaded for either type.
Note: No need to modify XSM as it has one size fits all check and
does not check for subcommands.
Note: No need to check KEXEC_FLAG_IN_PROGRESS (and error out of
kexec_status()) as this flag is set only once by the first/only
cpu on the crash path.
Note: This is just the Xen side of the hypercall, kexec-tools patch
to come separately.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Eric DeVolder <eric.devolder@oracle.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
When iterating through CPUID leaves to generating a policy, libxc will clip
itself at the hardcoded maxima, meaning that no data outside of the hardcoded
maxima are provided to Xen (in turn, causing Xen to return zeros if these
leaves are requested.)
The HVM code also clips the max_leaf data reported to the guest, but the PV
side didn't.
This results in a PV guest using the emulated CPUID, or via Xen using CPUID
faulting, to observe a max_leaf higher than the toolstack wants, although with
zeros being returned in the intervening leaves.
Fix the PV side to behave like the HVM side, and clip the max_leaf values in
leaf 0 and 0x80000000.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
The hypervisor expects the timeout from the hypercall to be in
nanoseconds, so document this correctly. Also correctly document
what happens when timeout is set to zero.
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com>
Add two new AVX512 subfeatures support for guest.
AVX512_4VNNIW:
Vector instructions for deep learning enhanced word variable precision.
AVX512_4FMAPS:
Vector instructions for deep learning floating-point single precision.
Signed-off-by: Luwei Kang <luwei.kang@intel.com>
Signed-off-by: He Chen <he.chen@linux.intel.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Currently hypervisor provides PV guest's CPUID(1).EBX[31:24] (initial
APIC ID) with contents of that field on the processor that launched
the guest. This results in the guest reporting different initial
APIC IDs across runs.
We should be consistent in how this value is reported, let's set
it to 0 (which is also what Linux guests expect).
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
[ wei: remove trailing whitespace in comment ]
Signed-off-by: Wei Liu <wei.liu2@citrix.com>
Release-acked-by: Wei Liu <wei.liu2@citrix.com>
Commit fac7f7 changed the value of ptr so that it points to the right memory
area, taking the page offset into account, but failed to remove this when
doing the unmap, which caused the region to not be unmapped. Fix this by not
modifying ptr and instead adding the page offset directly in the memcpy
call.
Coverity-ID: 1394285
Reported-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Release-acked-by: Wei Liu <wei.liu2@citrix.com>
in one sub-call: XEN_SYSCTL_TMEM_OP_GET_POOLS.
These operations are used during the save process of migration.
Instead of doing 64 hypercalls lets do just one. We modify
the 'struct xen_tmem_client' structure (used in
XEN_SYSCTL_TMEM_OP_[GET|SET]_CLIENT_INFO) to have an extra field
'nr_pools'. Armed with that the code slurping up pages from the
hypervisor can allocate a big enough structure (struct tmem_pool_info)
to contain all the active pools. And then just iterate over each
one and save it in the stream.
We are also re-using one of the subcommands numbers for this,
as such the XEN_SYSCTL_INTERFACE_VERSION should be incremented
and that was done in the patch titled:
"tmem/libxc: Squash XEN_SYSCTL_TMEM_OP_[SET|SAVE].."
In the xc_tmem_[save|restore] we also added proper memory handling
of the 'buf' and 'pools'. Because of the loops and to make it as
easy as possible to review we add a goto label and for almost
all error conditions jump in it.
The include for inttypes is required for the PRId64 macro to
work (which is needed to compile this code under 32-bit).
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
That is what they are used for. Lets make it more clear.
Of all the various sub-commands, the only one that needed
semantic change is XEN_SYSCTL_TMEM_OP_SAVE_BEGIN. That in the
past used 'arg1', and now we are moving it to use 'arg'.
Since that code is only used during migration which is tied
to the toolstack it is OK to change it.
We should increment the XEN_SYSCTL_INTERFACE_VERSION because
of this, and that was fortunatly done in the patch titled:
"tmem/libxc: Squash XEN_SYSCTL_TMEM_OP_[SET|SAVE].."
While at it, also fix xc_tmem_control_oid to properly handle
the 'buf' and bounce it as appropiate.
Acked-by: Andrew cooper <andrew.cooper3@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
return values. For success they used to be 1 ([SAVE,RESTORE]_BEGIN),
0 if guest did not have any tmem (but only for SAVE_BEGIN), and
-1 for any type of failure.
And SAVE_END (which you would think would mirror SAVE_BEGIN)
had 0 for success and -1 if guest did not any tmem enabled for it.
This is confusing. Now the code will return 0 if the operation was
success. Various XEN_EXX values are returned if tmem is not enabled
or the operation could not performed.
The xc_tmem.c code only needs one place to check - where we use
SAVE_BEGIN. The place where RESTORE_BEGIN is used will have errno
with the proper error value and return will be -1, so will still
fail properly.
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Specifically:
XEN_SYSCTL_TMEM_OP_SET_[WEIGHT,COMPRESS] are now done via:
XEN_SYSCTL_TMEM_SET_CLIENT_INFO
and XEN_SYSCTL_TMEM_OP_SAVE_GET_[VERSION,MAXPOOLS,
CLIENT_WEIGHT, CLIENT_FLAGS] can now be retrieved via:
XEN_SYSCTL_TMEM_GET_CLIENT_INFO
All this information is now in 'struct xen_tmem_client' and
that is what we pass around.
We also rev up the XEN_SYSCTL_INTERFACE_VERSION as we are
re-using the value number of the deleted ones (and henceforth
the information is retrieved differently).
On the toolstack, prior to this patch, the xc_tmem_control
would use the bounce buffer only when arg1 was set and the cmd
was to list. With the 'XEN_SYSCTL_TMEM_OP_SET_[WEIGHT|COMPRESS]'
that made sense as the 'arg1' would have the value. However
for the other ones (say XEN_SYSCTL_TMEM_OP_SAVE_GET_POOL_UUID)
the 'arg1' would be the length of the 'buf'. If this
confusing don't despair, patch patch titled:
tmem/xc_tmem_control: Rename 'arg1' to 'len' and 'arg2' to arg.
takes care of that.
The acute reader of the toolstack code will discover that
we only used the bounce buffer for LIST, not for any other
subcommands that used 'buf'!?! Which means that the contents
of 'buf' would never be copied back to the calleer 'buf'!
The author is not sure how this could possibly work, perhaps Xen 4.1
(when this was introduced) was more relaxed about the bounce buffer
being enabled. Anyhow this fixes xc_tmem_control to do it for
any subcommand that has 'arg1'.
Lastly some of the checks in xc_tmem_[restore|save] are removed
as they can't ever be reached (not even sure how they could
have been reached in the original submission). One of them
is the check for the weight against -1 when in fact the
hypervisor would never have provided that value.
Now the checks are simple - as the hypercall always returns
->version and ->maxpools (which is mirroring how it was done
prior to this patch). But if one wants to check the if a guest
has any tmem activity then the patch titled
"tmem: Batch and squash XEN_SYSCTL_TMEM_OP_SAVE_GET_POOL_
[FLAGS,NPAGES,UUID] in one sub-call: XEN_SYSCTL_TMEM_OP_GET_POOLS."
adds an ->nr_pools to check for that.
Also we add the check for ->version and ->maxpools and remove
the TODO.
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
No functional change. We do this to prepare for another
entry to be added in the union. See patch titled:
"tmem/libxc: Squash XEN_SYSCTL_TMEM_OP_[SET|SAVE]"
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
It is not used by anything. Its intent was to complement
the 'weight' attribute but there hadn't been any request for this.
If there is a need to resurface it, it can be integrated back
via the XEN_SYSCTL_TMEM_SET_CLIENT_INFO introduced in
"tmem/libxc: Squash XEN_SYSCTL_TMEM_OP_[SET|SAVE].."
Acked-by: Wei Liu <wei.liu2@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
The only thing this hypercall returns is TMEM_SPEC_VERSION.
The comment around is also misleading - this call does not
do any domain operation.
Acked-by: Wei Liu <wei.liu2@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
The ARM SMC instructions are already configured to trap to Xen by default. In
this patch we allow a user-space process in a privileged domain to receive
notification of when such event happens through the vm_event subsystem by
introducing the PRIVILEGED_CALL type.
The intended use-case for this feature is for a monitor application to be able
insert tap-points into the domU kernel-code. For this task only unconditional
SMC instruction should be used.
Signed-off-by: Tamas K Lengyel <tamas.lengyel@zentific.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Acked-by: Razvan Cojocaru <rcojocaru@bitdefender.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
unsigned int is only 4-byte long and "4" is treated as int. The shift
would overflow.
Use unsigned long type, calculate the bits to shift before shifting
instead of shifting twice.
Caught by clang compilation test.
Signed-off-by: Wei Liu <wei.liu2@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
The main purpose of the patch is to provide the xen-libxc
plumbing necessary to be able to change the value of the
ratelimit_us parameter online, for Credit2 (like it is
already for Credit1).
While there:
- mention in the Xen logs when rate limiting was enables
and is being disabled (and vice-versa);
- fix csched2_sys_cntl() which was always returning
-EINVAL in the XEN_SYSCTL_SCHEDOP_putinfo case.
And also:
- fix style of an if in csched_sys_cntl();
- fix the style of the switch in csched2_sys_cntl();
Signed-off-by: Dario Faggioli <dario.faggioli@citrix.com>
Reviewed-by: George Dunlap <george.dunlap@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Provide ability to load multiple ACPI modules. Thie feature is needed
by PVHv2 guests and will be used in subsequent patches.
We assume that PVHv2 guests do not load their ACPI modules specified
in the configuration file. We can extend support for that in the future
if desired.
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Only define BUILD_BUG_ON when there isn't one already, because mini-os
currently leaks that.
Signed-off-by: Wei Liu <wei.liu2@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Currently it is only possible to set mem_access restrictions only for
a contiguous range of GFNs (or, as a particular case, for a single GFN).
This patch introduces a new libxc function taking an array of GFNs.
The alternative would be to set each page in turn, using a userspace-HV
roundtrip for each call, and triggering a TLB flush per page set.
Signed-off-by: Razvan Cojocaru <rcojocaru@bitdefender.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Tamas K Lengyel <tamas@tklengyel.com>
Acked-by: Julien Grall <julien.grall@arm.com>
Acked-by: George Dunlap <george.dunlap@citrix.com>
It is possible, when normalising a PV pagetable that the table has been freed
and reused for something else by the guest.
In such a case, data read might no longer be a pagetable, and fail the
truncation check. However, this should only be fatal if we encounter such a
page in the paused phase.
This check is now consistent with all other checks in the same area.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Wei Liu <wei.liu2@citrix.com>
Commit 91e204d37f ("libxc: try to find
last used pfn when migrating") introduced a bug for the case of a
domain supporting the virtual mapped linear p2m list: the maximum pfn
of the domain calculated from the p2m memory allocation might be too
low.
Correct this.
Reported-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Tested-by: Stefan Bader <stefan.bader@canonical.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
... and load BIOS/UEFI firmware into guest memory.
This adds a new firmware module, system_firmware_module. It is loaded in
the guest memory and final location is provided to hvmloader via the
hvm_start_info struct.
This patch create the hvm_start_info struct for HVM guest that have a
device model, so this is now common code with HVM guest without device
model.
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
This patch use xc_dom_alloc_segment() to allocate the memory space for the
ACPI modules and the SMBIOS modules. This is to replace the arbitrary
placement of 1MB (+ extra for MB alignement) after the hvmloader image.
This patch can help if one add extra ACPI table and hvmloader contain
OVMF (OVMF is a 2MB binary), as in that case the extra ACPI table could
easily be loaded past the address 4MB, but hvmloader use a range of
memory from 4MB to 10MB to perform tests and in the process, clears the
memory, before loading the modules.
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Instead of having several representation of hvm_start_info in C, define
it in public/arch-x86/hvm/start_info.h so both libxc and hvmloader can
use it.
Also move the comment describing the binary format to be alongside the
C struct.
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
That line doesn't reveal much information to ordinary users.
Change that to debug output.
Signed-off-by: Wei Liu <wei.liu2@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Currently mem-sharing can be performed on a page-by-page basis from the control
domain. However, this process is quite wasteful when a range of pages have to
be deduplicated.
This patch introduces a new mem_sharing memop for range sharing where
the user doesn't have to separately nominate each page in both the source and
destination domain, and the looping over all pages happen in the hypervisor.
This significantly reduces the overhead of sharing a range of memory.
Signed-off-by: Tamas K Lengyel <tamas.lengyel@zentific.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
This allows a toolstack to identify whether a running domain is using hardware
assisted paging or not.
The appropriate tests differ by architecture, so introduce
arch_get_domain_info(). ARM unconditionally sets the new flag, while x86
checks with the paging subsystem first.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Reviewed-by: Julien Grall <julien.grall@arm.com>
Reviewed-by: George Dunlap <george.dunlap@citrix.com>
Current code incorrectly adds 1 to full register instead of
incrementing the field in bits 15:12.
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>