[Xen-devel] [PATCH RFC v2 00/30] x86: Improvements to cpuid handling for guests

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

Presented here is v2 of my work to improve cpuid levelling for guests.

This series is available in git form at:
  http://xenbits.xen.org/git-http/people/andrewcoop/xen.git levelling-v2

Major changes from v1 include a rebase onto staging, reworking of the
automatic generation of cpu featureset information, and fixes to xsave
handling for PV guests on Intel.

There is still an outstanding issue with xsave handling for PV guests on AMD
which I am investigating, and is the cause for the series still being RFC.

The current cpuid code, both in the hypervisor and toolstack, has grown
organically for a very long time, and is flawed in many ways.  This series
focuses specifically on the fixing the bits pertaining to the visible
features, and I will be fixing other areas in future work (e.g. per-core,
per-package values, auditing of incoming migration values, etc.)

These changes alter the workflow of cpuid handling as follows:

Xen boots and evaluates its current capabilities.  It uses this information to
calculate the maximum featuresets it can provide to guests, and provides this
information for toolstack consumption.  A toolstack may then calculate a safe
set of features (taking into account migratability), and sets a guests cpuid
policy.  Xen then takes care of context switching the levelling state.

In particular, this means that PV guests may have different levels while
running on the same host, an option which was not previously available.

Andrew Cooper (30):
  xen/x86: Drop X86_FEATURE_3DNOW_ALT
  xen/x86: Do not store VIA/Cyrix/Centaur CPU features
  xen/x86: Drop cpuinfo_x86.x86_power
  xen/x86: Improvements to pv_cpuid()
  xen/public: Export cpu featureset information in the public API
  xen/x86: Script to automatically process featureset information
  xen/x86: Collect more cpuid feature leaves
  xen/x86: Mask out unknown features from Xen's capabilities
  xen/x86: Store antifeatures inverted in a featureset
  xen/x86: Annotate VM applicability in featureset
  xen/x86: Calculate maximum host and guest featuresets
  xen/x86: Generate deep dependencies of features
  xen/x86: Clear dependent features when clearing a cpu cap
  xen/x86: Improve disabling of features which have dependencies
  xen/x86: Improvements to in-hypervisor cpuid sanity checks
  x86/cpu: Move set_cpumask() calls into c_early_init()
  x86/cpu: Common infrastructure for levelling context switching
  x86/cpu: Rework AMD masking MSR setup
  x86/cpu: Rework Intel masking/faulting setup
  x86/cpu: Context switch cpuid masks and faulting state in
    context_switch()
  x86/pv: Provide custom cpumasks for PV domains
  x86/domctl: Update PV domain cpumasks when setting cpuid policy
  xen+tools: Export maximum host and guest cpu featuresets via SYSCTL
  tools/libxc: Modify bitmap operations to take void pointers
  tools/libxc: Use public/featureset.h for cpuid policy generation
  tools/libxc: Expose the automatically generated cpu featuremask
    information
  tools: Utility for dealing with featuresets
  tools/libxc: Wire a featureset through to cpuid policy logic
  tools/libxc: Use featuresets rather than guesswork
  tools/libxc: Calculate xstate cpuid leaf from guest information

 .gitignore                                  |   2 +
 tools/libxc/Makefile                        |   9 +
 tools/libxc/include/xenctrl.h               |  21 +-
 tools/libxc/xc_bitops.h                     |  21 +-
 tools/libxc/xc_cpufeature.h                 | 147 --------
 tools/libxc/xc_cpuid_x86.c                  | 550 ++++++++++++++++------------
 tools/libxl/libxl_cpuid.c                   |   2 +-
 tools/misc/Makefile                         |   4 +
 tools/misc/xen-cpuid.c                      | 394 ++++++++++++++++++++
 tools/ocaml/libs/xc/xenctrl.ml              |   3 +
 tools/ocaml/libs/xc/xenctrl.mli             |   4 +
 tools/ocaml/libs/xc/xenctrl_stubs.c         |  37 +-
 tools/python/xen/lowlevel/xc/xc.c           |   2 +-
 xen/arch/x86/Makefile                       |   1 +
 xen/arch/x86/apic.c                         |   2 +-
 xen/arch/x86/cpu/amd.c                      | 309 ++++++++++------
 xen/arch/x86/cpu/centaur.c                  |   3 -
 xen/arch/x86/cpu/common.c                   |  51 ++-
 xen/arch/x86/cpu/intel.c                    | 269 +++++++++-----
 xen/arch/x86/cpuid.c                        | 227 ++++++++++++
 xen/arch/x86/domain.c                       |  17 +-
 xen/arch/x86/domctl.c                       |  88 +++++
 xen/arch/x86/hvm/hvm.c                      |  56 ++-
 xen/arch/x86/setup.c                        |   3 +
 xen/arch/x86/sysctl.c                       |  66 ++++
 xen/arch/x86/traps.c                        | 223 ++++++-----
 xen/arch/x86/xstate.c                       |   6 +-
 xen/include/Makefile                        |  10 +
 xen/include/asm-x86/cpufeature.h            | 174 +--------
 xen/include/asm-x86/cpuid.h                 |  44 +++
 xen/include/asm-x86/domain.h                |   2 +
 xen/include/asm-x86/processor.h             |  31 +-
 xen/include/public/arch-x86/cpufeatureset.h | 216 +++++++++++
 xen/include/public/sysctl.h                 |  25 ++
 xen/tools/gen-cpuid.py                      | 329 +++++++++++++++++
 35 files changed, 2410 insertions(+), 938 deletions(-)
 delete mode 100644 tools/libxc/xc_cpufeature.h
 create mode 100644 tools/misc/xen-cpuid.c
 create mode 100644 xen/arch/x86/cpuid.c
 create mode 100644 xen/include/asm-x86/cpuid.h
 create mode 100644 xen/include/public/arch-x86/cpufeatureset.h
 create mode 100755 xen/tools/gen-cpuid.py

-- 
2.1.4


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