[Xen-devel] [PATCH v5 0/6] 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 Server 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 frequency. 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.

If the destination host supports VMX TSC scaling, this patchset allows
guest programs in a HVM container in the default TSC mode or PVRDTSCP
(native_paravirt) TSC mode to observe the same TSC frequency across
the migration.

Changes in v5:
 * v4 patch 1 - 3 have been committed so they are not included in v5.
 * v4 patch 5 "x86: Add functions for 64-bit integer arithmetic" is
   removed in v5. All math64 functions are inlined in v5.
 * v5 patch 1 corresponds to v4 patch 4.
   v5 patch 2 - 6 correspond to v4 patch 6 - 10.
 * Other changes are logged in each patch respectively.
 * Previous R-b and A-b (from Boris Ostrovsky, Jan Beulich and Kevin
   Tian) for all patches except patch 4 are removed because of above
   changes.

Changes in v4:
 * v3 patch 1&2 have been committed so they are not included in v4.
 * v3 patch 11 "x86/hvm: Detect TSC scaling through hvm_funcs" is merged
   early into v4 patch 4 "x86/hvm: Collect information of TSC scaling ratio".
 * v4 patch 1 - 8 correspond to v3 patch 3 - 10.
   v4 patch 9 - 10 correspond to v3 patch 12 - 13.
 * Other changes are logged in each patch respectively.

Changes in v3:
 * v2 patch 1&2 have been merged so they do not appear in v3.
 * Patch 1 - 6 correspond to v2 patch 3 - 8. Patch 7 is new.
   Patch 8 - 13 correspond to v2 patch 9 - 14.
 * Other changes are logged in each patch respectively.

Changes in v2:
 * Remove unnecessary v1 patch 1&13.
 * Add and move all bug-fix patches to the beginning of this series.
   (Patch 1 - 6)
 * Update changes in tsc_set_info() and tsc_get_info() to make both
   functions consistent with each other. (Patch 2 - 4)
 * Move a part of scaling logic out of [vmx|svm]_set_tsc_offset().
   (Patch 7)
 * Remove redundant hvm_funcs.tsc_scaling_ratio_rsvd. (Patch 8)
 * Reimplement functions that calculate TSC ratio and scale TSC.
   (Patch 9&10)
 * Merge setting VMX TSC multiplier into patch 13.
 * Move initialing tsc_scaling_ratio in VMX ahead to
   vmx_vcpu_initialise() so as to make construct_vmcs() naturally
   use this field instead of a constant. (Patch 13)
 * Update documents related to tsc_mode.
 * Other code cleanup and style fixes.

Haozhong Zhang (6):
  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: Move saving/loading vcpu's TSC to common code
  vmx: Add VMX RDTSC(P) scaling support
  docs: Add descriptions of TSC scaling in xl.cfg and tscmode.txt

 docs/man/xl.cfg.pod.5              | 14 ++++++++-
 docs/misc/tscmode.txt              | 21 +++++++++++++
 xen/arch/x86/hvm/hvm.c             | 62 +++++++++++++++++++++++++++++++++++---
 xen/arch/x86/hvm/svm/svm.c         | 21 +++++--------
 xen/arch/x86/hvm/vmx/vmcs.c        | 12 ++++++--
 xen/arch/x86/hvm/vmx/vmx.c         | 22 +++++++++++---
 xen/arch/x86/time.c                | 17 +++++++----
 xen/include/asm-x86/hvm/domain.h   |  2 ++
 xen/include/asm-x86/hvm/hvm.h      | 26 +++++++++++++++-
 xen/include/asm-x86/hvm/svm/svm.h  |  3 --
 xen/include/asm-x86/hvm/vmx/vmcs.h |  7 +++++
 11 files changed, 169 insertions(+), 38 deletions(-)

-- 
2.7.1


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