[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

[Xen-devel] [PATCH v5 0/6] Add VMX TSC scaling support

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

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 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(-)


Xen-devel mailing list



Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.