remove unnecessary state check and
add pre-condition for vcpu APIs.
Tracked-On: #4320
Signed-off-by: Mingqiang Chi <mingqiang.chi@intel.com>
Reviewed-by: Jason Chen CJ <jason.cj.chen@intel.com>
Acked-by: Eddie Dong <eddie.dong@intel.com>
check the vm state in hypercall api,
add pre-condition for vm api.
Tracked-On: #4320
Signed-off-by: Mingqiang Chi <mingqiang.chi@intel.com>
Reviewed-by: Jason Chen CJ <jason.cj.chen@intel.com>
Acked-by: Eddie Dong <eddie.dong@intel.com>
ACRN disables Snoop Control in VT-d DMAR engines for simplifing the
implementation. Also, since the snoop behavior of PCIE transactions
can be controlled by guest drivers, some devices may take the advantage
of the NO_SNOOP_ATTRIBUTE of PCIE transactions for better performance
when snoop is not needed. No matter ACRN enables or disables Snoop
Control, the DMA operations of passthrough devices behave correctly
from guests' point of view.
This patch is used to clean all the snoop related code.
Tracked-On: #4509
Signed-off-by: Xiaoguang Wu <xiaoguang.wu@intel.com>
Reviewed-by: Binbin Wu <binbin.wu@intel.com>
Acked-by: Eddie Dong <eddie.dong@Intel.com>
Waag will send NMIs to all its cores during reboot. But currently,
NMI cannot be injected to vcpu which is in HLT state.
To fix the problem, need to wakeup target vcpu, and inject NMI through
interrupt-window.
Tracked-On: #4620
Signed-off-by: Conghui Chen <conghui.chen@intel.com>
Acked-by: Eddie Dong <eddie.dong@intel.com>
Currently vlapic_build_id() uses vcpu_id to retrieve the lapic_id
per_cpu variable:
vlapic_id = per_cpu(lapic_id, vcpu->vcpu_id);
SOS vcpu_id may not equal to pcpu_id, and in that case it runs into
problems. For example, if any pre-launched VMs are launched on PCPUs
whose IDs are smaller than any PCPU IDs that are used by SOS.
This patch fixes the issue and simplify the code to create or get
vapic_id by:
- assign vapic_id in create_vlapic(), which now takes pcpu_id as input
argument, and save it in the new field: vlapic->vapic_id, which will
never be changed.
- simplify vlapic_get_apicid() by returning te saved vapid_id directly.
- remove vlapic_build_id().
- vlapic_init() is only called once, merge it into vlapic_create().
Tracked-On: #4268
Signed-off-by: Zide Chen <zide.chen@intel.com>
Acked-by: Eddie Dong <eddie.dong@intel.com>
Maintain a per-pCPU array of vCPUs (struct acrn_vcpu *vcpu_array[CONFIG_MAX_VM_NUM]),
one VM cannot have multiple vCPUs share one pcpu, so we can utilize this property
and use the containing VM's vm_id as the index to the vCPU array:
In create_vcpu(), we simply do:
per_cpu(vcpu_array, pcpu_id)[vm->vm_id] = vcpu;
In offline_vcpu():
per_cpu(vcpu_array, pcpuid_from_vcpu(vcpu))[vcpu->vm->vm_id] = NULL;
so basically we use the containing VM's vm_id as the index to the vCPU array,
as well as the index of posted interrupt IRQ/vector pair that are assigned
to this vCPU:
0: first vCPU and first posted interrupt IRQs/vector pair
(POSTED_INTR_IRQ/POSTED_INTR_VECTOR)
...
CONFIG_MAX_VM_NUM-1: last vCPU and last posted interrupt IRQs/vector pair
((POSTED_INTR_IRQ + CONFIG_MAX_VM_NUM - 1U)/(POSTED_INTR_VECTOR + CONFIG_MAX_VM_NUM - 1U)
In the posted interrupt handler, it will do the following:
Translate the IRQ into a zero based index of where the vCPU
is located in the vCPU list for current pCPU. Once the
vCPU is found, we wake up the waiting thread and record
this request as ACRN_REQUEST_EVENT
Tracked-On: #4506
Signed-off-by: dongshen <dongsheng.x.zhang@intel.com>
Reviewed-by: Eddie Dong <eddie.dong@Intel.com>
Signed-off-by: dongshen <dongsheng.x.zhang@intel.com>
This is a preparation patch for adding support for VT-d PI
related vCPU scheduling.
ACRN does not support vCPU migration, one vCPU always runs on
the same pCPU, so PI's ndst is never changed after startup.
VCPUs of a VM won’t share same pCPU. So the maximum possible number
of VCPUs that can run on a pCPU is CONFIG_MAX_VM_NUM.
Allocate unique Activation Notification Vectors (ANV) for each vCPU
that belongs to the same pCPU, the ANVs need only be unique within each
pCPU, not across all vCPUs. This reduces # of pre-allocated ANVs for
posted interrupts to CONFIG_MAX_VM_NUM, and enables ACRN to avoid
switching between active and wake-up vector values in the posted
interrupt descriptor on vCPU scheduling state changes.
A total of CONFIG_MAX_VM_NUM consecutive IRQs/vectors are reserved
for posted interrupts use.
The code first initializes vcpu->arch.pid.control.bits.nv dynamically
(will be added in subsequent patch), the other code shall use
vcpu->arch.pid.control.bits.nv instead of the hard-coded notification vectors.
Rename some functions:
apicv_post_intr --> apicv_trigger_pi_anv
posted_intr_notification --> handle_pi_notification
setup_posted_intr_notification --> setup_pi_notification
Tracked-On: #4506
Signed-off-by: dongshen <dongsheng.x.zhang@intel.com>
Reviewed-by: Eddie Dong <eddie.dong@Intel.com>
Given the vcpumask, check if the IRQ is single destination
and return the destination vCPU if so, the address of associated PI
descriptor for this vCPU can then be passed to dmar_assign_irte() to
set up the posted interrupt IRTE for this device.
For fixed mode interrupt delivery, all vCPUs listed in vcpumask should
service the interrupt requested. But VT-d PI cannot support multicast/broadcast
IRQs, it only supports single CPU destination. So the number of vCPUs
shall be 1 in order to handle IRQ in posted mode for this device.
Add pid_paddr to struct intr_source. If platform_caps.pi is true and
the IRQ is single-destination, pass the physical address of the destination
vCPU's PID to ptirq_build_physical_msi and dmar_assign_irte
Tracked-On: #4506
Signed-off-by: dongshen <dongsheng.x.zhang@intel.com>
Reviewed-by: Eddie Dong <eddie.dong@Intel.com>
Add platform_caps.c to maintain platform related information
Set platform_caps.pi to true if all iommus are posted interrupt capable, false
otherwise
If lapic passthru is not configured and platform_caps.pi is true, the vm
may be able to use posted interrupt for a ptdev, if the ptdev's IRQ is
single-destination
Tracked-On: #4506
Signed-off-by: dongshen <dongsheng.x.zhang@intel.com>
Reviewed-by: Eddie Dong <eddie.dong@Intel.com>
EPT table can be changed concurrently by more than one vcpus.
This patch add a lock to protect the add/modify/delete operations
from different vcpus concurrently.
Tracked-On: #4253
Signed-off-by: Jian Jun Chen <jian.jun.chen@intel.com>
Reviewed-by: Li, Fei1 <fei1.li@intel.com>
This commit allows hypervisor to allocate cache to vcpu by assigning different clos
to vcpus of a same VM.
For example, we could allocate different cache to housekeeping core and real-time core
of an RTVM in order to isolate the interference of housekeeping core via cache hierarchy.
Tracked-On: #4566
Signed-off-by: Yan, Like <like.yan@intel.com>
Reviewed-by: Chen, Zide <zide.chen@intel.com>
Acked-by: Eddie Dong <eddie.dong@intel.com>
As ACRN prepares to support servers with large amounts of memory
current logic to allocate space for 4K pages of EPT at compile time
will increase the size of .bss section of ACRN binary.
Bootloaders could run into a situation where they cannot
find enough contiguous space to load ACRN binary under 4GB,
which is typically heavily fragmented with E820 types Reserved,
ACPI data, 32-bit PCI hole etc.
This patch does the following
1) Works only for "direct" mode of vboot
2) reserves space for 4K pages of EPT, after boot by parsing
platform E820 table, for all types of VMs.
Size comparison:
w/o patch
Size of DRAM Size of .bss
48 GB 0xe1bbc98 (~226 MB)
128 GB 0x222abc98 (~548 MB)
w/ patch
Size of DRAM Size of .bss
48 GB 0x1991c98 (~26 MB)
128 GB 0x1a81c98 (~28 MB)
Tracked-On: #4563
Signed-off-by: Sainath Grandhi <sainath.grandhi@intel.com>
Acked-by: Eddie Dong <eddie.dong@intel.com>
hv: vtd: removed is_host (always false) and is_tt_ept (always true) member
variables of struct iommu_domain and related codes since the values are
always determined.
Tracked-On: #4535
Signed-off-by: Qian Wang <qian1.wang@intel.com>
Reviewed-by: Binbin Wu <binbin.wu@intel.com>
Acked-by: Eddie Dong <eddie.dong@intel.com>
We could use container_of to get vcpu structure pointer from vmtrr. So vcpu
structure pointer is no need in vmtrr structure.
Tracked-On: #4550
Signed-off-by: Li Fei1 <fei1.li@intel.com>
We could use container_of to get vcpu/vm structure pointer from vlapic. So vcpu/vm
structure pointer is no need in vlapic structure.
Tracked-On: #4550
Signed-off-by: Li Fei1 <fei1.li@intel.com>
Exend union dmar_ir_entry to support VT-d posted interrupts.
Rename some fields of union dmar_ir_entry:
entry --> value
sw_bits --> avail
Tracked-On: #4506
Signed-off-by: dongshen <dongsheng.x.zhang@intel.com>
Reviewed-by: Eddie Dong <eddie.dong@Intel.com>
Pass intr_src and dmar_ir_entry irte as pointers to dmar_assign_irte(),
which fixes the "Attempt to change parameter passed by value" MISRA C violation.
A few coding style fixes
Tracked-On: #4506
Signed-off-by: dongshen <dongsheng.x.zhang@intel.com>
Reviewed-by: Eddie Dong <eddie.dong@Intel.com>
For CPU side posted interrupts, it only uses bit 0 (ON) of the PI's 64-bit control
, other bits are don't care. This is not the case for VT-d posted
interrupts, define more bit fields for the PI's 64-bit control.
Use bitmap functions to manipulate the bit fields atomically.
Some MISRA-C violation and coding style fixes
Tracked-On: #4506
Signed-off-by: dongshen <dongsheng.x.zhang@intel.com>
Reviewed-by: Eddie Dong <eddie.dong@Intel.com>
The posted interrupt descriptor is more of a vmx/vmcs concept than a vlapic
concept. struct acrn_vcpu_arch stores the vmx/vmcs info, so put struct pi_desc
in struct acrn_vcpu_arch.
Remove the function apicv_get_pir_desc_paddr()
A few coding style/typo fixes
Tracked-On: #4506
Signed-off-by: dongshen <dongsheng.x.zhang@intel.com>
Reviewed-by: Eddie Dong <eddie.dong@Intel.com>
Rename struct vlapic_pir_desc to pi_desc
Rename struct member and local variable pir_desc to pid
pir=posted interrupt request, pi=posted interrupt
pid=posted interrupt descriptor
pir is part of pi descriptor, so it is better to use pi instead of pir
struct pi_desc will be moved to vmx.h in subsequent commit.
Tracked-On: #4506
Signed-off-by: dongshen <dongsheng.x.zhang@intel.com>
Reviewed-by: Eddie Dong <eddie.dong@Intel.com>
The cupid() can be replaced with cupid_subleaf, which is more clear.
Having both APIs makes reading difficult.
Tracked-On: #4526
Signed-off-by: Li Fei1 <fei1.li@intel.com>
For SOS VM, when the target platform has multiple IO-APICs, there
should be equal number of virtual IO-APICs.
This patch adds support for emulating multiple vIOAPICs per VM.
Tracked-On: #4151
Signed-off-by: Sainath Grandhi <sainath.grandhi@intel.com>
Acked-by: Eddie Dong <eddie.dong@Intel.com>
MADT is used to specify the GSI base for each IO-APIC and the number of
interrupt pins per IO-APIC is programmed into Max. Redir. Entry register of
that IO-APIC.
On platforms with multiple IO-APICs, there can be holes in the GSI space.
For example, on a platform with 2 IO-APICs, the following configuration has
a hole (from 24 to 31) in the GSI space.
IO-APIC 1: GSI base - 0, number of pins - 24
IO-APIC 2: GSI base - 32, number of pins - 8
This patch also adjusts the size for variables used to represent the total
number of IO-APICs on the system from uint16_t to uint8_t as the ACPI MADT
uses only 8-bits to indicate the unique IO-APIC IDs.
Tracked-On: #4151
Signed-off-by: Sainath Grandhi <sainath.grandhi@intel.com>
Acked-by: Eddie Dong <eddie.dong@Intel.com>
As ACRN prepares to support platforms with multiple IO-APICs,
GSI is a better way to represent physical and virtual INTx interrupt
source.
1) This patch replaces usage of "pin" with "gsi" whereever applicable
across the modules.
2) PIC pin to gsi is trickier and needs to consider the usage of
"Interrupt Source Override" structure in ACPI for the corresponding VM.
Tracked-On: #4151
Signed-off-by: Sainath Grandhi <sainath.grandhi@intel.com>
Acked-by: Eddie Dong <eddie.dong@Intel.com>
Reverts 538ba08c: hv:Add vpin to ptdev entry mapping for vpic/vioapic
ACRN uses an array of size per VM to store ptirq entries against the vIOAPIC pin
and an array of size per VM to store ptirq entries against the vPIC pin.
This is done to speed up "ptirq entry" lookup at runtime for Level triggered
interrupts in API ptirq_intx_ack used on EOI.
This patch switches the lookup API for INTx interrupts to the API,
ptirq_lookup_entry_by_sid
This could add delay to processing EOI for Level triggered interrupts.
Trade-off here is space saved for array/s of size CONFIG_MAX_IOAPIC_LINES with 8 bytes
per data. On a server platform, ACRN needs to emulate multiple vIOAPICs for
SOS VM, same as the number of physical IO-APICs. Thereby ACRN would need around
10 such arrays per VM.
Removes the need of "pic_pin" except for the APIs facing the hypercalls
hcall_set_ptdev_intr_info, hcall_reset_ptdev_intr_info
Tracked-On: #4151
Signed-off-by: Sainath Grandhi <sainath.grandhi@intel.com>
Acked-by: Eddie Dong <eddie.dong@Intel.com>
There're some cases the SOS (higher severity guest) needs to access the
post-launched VM (lower severity guest) PCI CFG space:
1. The SR-IOV PF needs to reset the VF
2. Some pass through device still need DM to handle some quirk.
In the case a device is assigned to a UOS and is not in a zombie state, the SOS
is able to access, if and only if the SOS has higher severity than the UOS.
Tracked-On: #4371
Signed-off-by: Li Fei1 <fei1.li@intel.com>
For a pre-launched VM, a region from PTDEV_HI_MMIO_START is used to store
64bit vBARs of PT devices which address is high than 4G. The region should
be located after all user memory space and be coverd by guest EPT address.
Tracked-On: #4458
Signed-off-by: Victor Sun <victor.sun@intel.com>
Acked-by: Eddie Dong <eddie.dong@intel.com>
ve820.c is a common file in arch/x86/guest/ now, so move function of
create_sos_vm_e820() to this file to make code structure clear;
Tracked-On: #4458
Signed-off-by: Victor Sun <victor.sun@intel.com>
Acked-by: Eddie Dong <eddie.dong@intel.com>
hypervisor/arch/x86/configs/$(BOARD)/ve820.c is used to store pre-launched
VM specific e820 entries according to memory configuration of customer.
It should be a scenario based configurations but we had to put it in per
board foler because of different board memory settings. This brings concerns
to customer on configuration orgnization.
Currently the file provides same e820 layout for all pre-launched VMs, but
they should have different e820 when their memory are configured differently.
Although we have acrn-config tool to generate ve802.c automatically, it
is not friendly to modify hardcoded ve820 layout manually, so the patch
changes the entries initialization method by calculating each entry item
in C code.
Tracked-On: #4458
Signed-off-by: Victor Sun <victor.sun@intel.com>
Acked-by: Eddie Dong <eddie.dong@intel.com>
Currently ept_pages_info[] is initialized with first element only that force
VM of id 0 using SOS EPT pages. This is incorrect for logical partition and
hybrid scenario. Considering SOS_RAM_SIZE and UOS_RAM_SIZE are configured
separately, we should use different ept pages accordingly.
So, the PRE_VM_NUM/SOS_VM_NUM and MAX_POST_VM_NUM macros are introduced to
resolve this issue. The macros would be generated by acrn-config tool when
user configure ACRN for their specific scenario.
One more thing, that when UOS_RAM_SIZE is less then 2GB, the EPT address
range should be (4G + PLATFORM_HI_MMIO_SIZE).
Tracked-On: #4458
Signed-off-by: Victor Sun <victor.sun@intel.com>
Acked-by: Eddie Dong <eddie.dong@intel.com>
VM needs to check if it owns this device before deiniting it.
Tracked-On: #4433
Signed-off-by: Yuan Liu <yuan1.liu@intel.com>
Signed-off-by: Yin Fengwei <fengwei.yin@intel.com>
Acked-by: Eddie Dong <eddie.dong@intel.com>
1. Renames DEFINE_IOAPIC_SID with DEFINE_INTX_SID as the virtual source can
be IOAPIC or PIC
2. Rename the src member of source_id.intx_id to ctlr to indicate interrupt
controller
2. Changes the type of src member of source_id.intx_id from uint32_t to
enum with INTX_CTLR_IOAPIC and INTX_CTLR_PIC
Tracked-On: #4447
Signed-off-by: Sainath Grandhi <sainath.grandhi@intel.com>
This is to enable relocation for code32.
- RIP relative addressing is available in x86-64 only so we manually add
relocation delta to the target symbols to fixup code32.
- both code32 and code64 need to load GDT hence both need to fixup GDT
pointer. This patch declares separate GDT pointer cpu_primary64_gdt_ptr
for code64 to avoid double fixup.
- manually fixup cpu_primary64_gdt_ptr in code64, but not rely on relocate()
to do that. Otherwise it's very confusing that symbols from same file could
be fixed up externally by relocate() or self-relocated.
- to make it clear, define a new symbol ld_entry_end representing the end of
the boot code that needs manually fixup, and use this symbol in relocate()
to filter out all symbols belong to the entry sections.
Tracked-On: #4441
Reviewed-by: Fengwei Yin <fengwei.yin@intel.com>
Signed-off-by: Zide Chen <zide.chen@intel.com>
This patch adds RDT MBA support to detect, configure and
and setup MBA throttle registers based on VM configuration.
Tracked-On: #3725
Signed-off-by: Vijay Dhanraj <vijay.dhanraj@intel.com>
Acked-by: Eddie Dong <eddie.dong@intel.com>
The init_one_dev_config is used to initialize a acrn_vm_pci_dev_config
SRIOV needs a explicit acrn_vm_pci_dev_config to create a VF vdev,so
refine it to return acrn_vm_pci_dev_config.
Tracked-On: #4433
Signed-off-by: Yuan Liu <yuan1.liu@intel.com>
Acked-by: Eddie Dong <eddie.dong@intel.com>
Current code avoid the rule 88 S in MISRA-C, so move xsaves and xrstors
assembler to individual functions.
Tracked-On: #4436
Signed-off-by: Conghui Chen <conghui.chen@intel.com>
Acked-by: Eddie Dong <eddie.dong@intel.com>
Make the SRIOV-Capable device invisible from SOS if there is
no room for its all virtual functions.
v2: fix a issue that if a PF has been dropped, the subsequent PF
will be dropped too even there is room for its VFs.
Tracked-On: #4433
Signed-off-by: Yuan Liu <yuan1.liu@intel.com>
Acked-by: Eddie Dong <eddie.dong@intel.com>
The init value for XCR0 and XSS should be the same with spec:
In SDM Vol1 13.3:
XCR0[0] is associated with x87 state (see Section 13.5.1). XCR0[0] is
always 1. The other bits in XCR0 are all 0 coming out of RESET.
The IA32_XSS MSR (with MSR index DA0H) is zero coming out of RESET.
The previous code try to fix the xsave area leak to other VMs during init
phase, but bring the error to linux. Besides, it cannot avoid the
possible leak in running phase. Need find a better solution.
Tracked-On: #4430
Signed-off-by: Conghui Chen <conghui.chen@intel.com>
Acked-by: Eddie Dong <eddie.dong@intel.com>
is not set
This patch does the following,
1. Removes RDT code if CONFIG_RDT_ENABLED flag is
not set.
2. Set the CONFIG_RDT_ENABLED flag only on platforms
that support RDT so that build scripts will automatically
reflect the config.
Tracked-On: #3715
Signed-off-by: Yin Fengwei <fengwei.yin@intel.com>
Signed-off-by: Vijay Dhanraj <vijay.dhanraj@intel.com>
Acked-by: Eddie Dong <eddie.dong@intel.com>
cache configuration.
This patch creates a generic infrastructure for
RDT resources instead of just L2 or L3 cache. This
patch also fixes L3 CAT config overwrite by L2 in
cases where both L2 and L3 CAT are supported.
Tracked-On: #3715
Signed-off-by: Vijay Dhanraj <vijay.dhanraj@intel.com>
Acked-by: Eddie Dong <eddie.dong@intel.com>
There can be times when user unknowinlgy enables
CONFIG_CAT_ENBALED SW flag, but the hardware might
not support L3 or L2 CAT. In such case software can
end up writing to the CAT MSRs which can cause
undefined results. The patch fixes the issue by
enabling CAT only when both HW as well software
via the CONFIG_CAT_ENABLED supports CAT.
The patch also address typo with "clos2prq_msr"
function name. It should be "clos2pqr_msr" instead.
PQR stands for platform qos register.
Tracked-On: #3715
Signed-off-by: Vijay Dhanraj <vijay.dhanraj@intel.com>
Acked-by: Eddie Dong <eddie.dong@intel.com>
Upcoming intel platforms can support both L2 and L3
but our current code only supports either L2 or L3 CAT.
So split the MSRs so that we can support allocation
for both L2 and L3.
This patch does the following,
1. splits programming of L2 and L3 cache resource
based on the resource ID.
2. Replace generic platform_clos_array struct with resource
specific struct in all the existing board.c files.
Tracked-On: #3715
Signed-off-by: Vijay Dhanraj <vijay.dhanraj@intel.com>
Acked-by: Eddie Dong <eddie.dong@intel.com>
As part of rdt cat refactoring, goal is to combine all rdt
specific features such as CAT under one module. So renaming
rdt resouce specific files such as cat.c/.h to generic rdt.c/.h
files.
Tracked-On: #3715
Signed-off-by: Vijay Dhanraj <vijay.dhanraj@intel.com>
Acked-by: Eddie Dong <eddie.dong@intel.com>
Initialize efi info of acrn mbi when boot from multiboot2 protocol, with
this patch hypervisor could get host efi info and pass it to Linux zeropage,
then make guest Linux possible to boot with efi environment;
Tracked-On: #4419
Signed-off-by: Victor Sun <victor.sun@intel.com>
Acked-by: Eddie Dong <eddie.dong@intel.com>
The patch re-arch boot component header files by:
- moving multiboot.h from include/arch/x86/ to boot/include/ and keep
this header for multiboot1 protocol data struct only;
- moving multiboot related MACROs in cpu_primary.S to multiboot.h;
- creating an independent boot.h to store acrn specific boot information
for other files' reference;
Tracked-On: #4419
Signed-off-by: Victor Sun <victor.sun@intel.com>
Acked-by: Eddie Dong <eddie.dong@intel.com>
BVT (Borrowed virtual time) scheduler is used to schedule vCPUs on pCPU.
It has the concept of virtual time, vCPU with earliset virtual time is
dispatched first.
Main concepts:
tick timer:
a period tick is used to measure the physcial time in units of MCU
(minimum charing unit).
runqueue:
thread in the runqueue is ordered by virtual time.
weight:
each thread receives a share of the pCPU in proportion to its
weight.
context switch allowance:
the physcial time by which the current thread is allowed to advance
beyond the next runnable thread.
warp:
a thread with warp enabled will have a change to minus a value (Wi)
from virtual time to achieve higher priority.
virtual time:
AVT: actual virtual time, advance in proportional to weight.
EVT: effective virtual time.
EVT <- AVT - ( warp ? Wi : 0 )
SVT: scheduler virtual time, the minimum AVT in the runqueue.
Tracked-On: #4410
Signed-off-by: Conghui Chen <conghui.chen@intel.com>
Signed-off-by: Shuo A Liu <shuo.a.liu@intel.com>
Acked-by: Eddie Dong <eddie.dong@intel.com>