[Xen-devel] [PATCH 00/13] Add VMX TSC scaling support

[Haozhong Zhang <haozhong.zhang@xxxxxxxxx>]

This patchset adds support for VMX TSC scaling feature which is
available on Intel Skylake CPU. The specification of VMX TSC scaling
can be found at
http://www.intel.com/content/www/us/en/processors/timestamp-counter-scaling-virtualization-white-paper.html

VMX TSC scaling allows guest TSC which is read by guest rdtsc(p)
instructions increases in a rate that is customized by the hypervisor
and can be different than the host TSC rate. Basically, VMX TSC
scaling adds a 64-bit field called TSC multiplier in VMCS so that, if
VMX TSC scaling is enabled, TSC read by guest rdtsc(p) instructions
will be calculated by the following formula:

  guest EDX:EAX = (Host TSC * TSC multiplier) >> 48 + VMX TSC Offset

where, Host TSC = Host MSR_IA32_TSC + Host MSR_IA32_TSC_ADJUST.

This patchset is composed of following four parts.
  1. PATCH 01 - 02 fix bugs in tsc_get_info() which could result in
     errors when VMX TSC scaling is used.
     
  2. PATCH 03 - 09 add/move the common parts of VMX TSC scaling and
     SVM TSC ratio to hvm.c and x86/time.c.
     
  3. PATCH 10 - 12 implement the VMX-specific code for supporting VMX
     TSC scaling.
     
  4. PATCH 13 adapts libxl for VMX TSC scaling (as well as SVM TSC
     ratio).

Haozhong Zhang (13):
  x86/time.c: Use system time to calculate elapsed_nsec in
    tsc_get_info()
  x86/time.c: Get the correct guest TSC rate in tsc_get_info()
  x86/hvm: Collect information of TSC scaling ratio
  x86/hvm: Setup TSC scaling ratio
  x86/hvm: Replace architecture TSC scaling by a common function
  x86/hvm: Scale host TSC when setting/getting guest TSC
  x86/hvm: Move saving/loading vcpu's TSC to common code
  x86/hvm: Detect TSC scaling through hvm_funcs in tsc_set_info()
  x86/time.c: Scale host TSC in pvclock properly
  vmx: Detect and initialize VMX RDTSC(P) scaling
  vmx: Use scaled host TSC to calculate TSC offset
  vmx: Add a call-back to apply TSC scaling ratio to hardware
  tools/libxl: Add 'vtsc_khz' option to set guest TSC rate

 tools/libxl/libxl_types.idl        |   1 +
 tools/libxl/libxl_x86.c            |   4 +-
 tools/libxl/xl_cmdimpl.c           |  22 ++++++++
 xen/arch/x86/hvm/hvm.c             | 110 +++++++++++++++++++++++++++++++++----
 xen/arch/x86/hvm/svm/svm.c         |  25 ++++++---
 xen/arch/x86/hvm/vmx/vmcs.c        |  11 +++-
 xen/arch/x86/hvm/vmx/vmx.c         |  39 +++++++++++--
 xen/arch/x86/time.c                |  33 ++++++++---
 xen/include/asm-x86/domain.h       |   2 +
 xen/include/asm-x86/hvm/hvm.h      |  19 +++++++
 xen/include/asm-x86/hvm/svm/svm.h  |   4 +-
 xen/include/asm-x86/hvm/vmx/vmcs.h |   7 +++
 12 files changed, 240 insertions(+), 37 deletions(-)

--
2.4.8


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