[Xen-devel] [PATCH v4 00/17] x86/PMU: Xen PMU PV support

[Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>]

Here is the fourth version PV (and now PVH) PMU patches.

The following patch series adds PMU support in Xen for PV(H)
guests. There is a companion patchset for Linux kernel. In addition,
another set of changes will be provided (later) for userland perf
code.

This version has following limitations:
* For accurate profiling of dom0/Xen dom0 VCPUs should be pinned.
* Hypervisor code is only profiled on processors that have running dom0 VCPUs
on them.
* No backtrace support.
* Will fail to load under XSM: we ran out of bits in permissions vector and
this needs to be fixed separately


A few notes that may help reviewing: 

* A shared data structure (xenpmu_data_t) between each PV VPCU and hypervisor 
CPU is used for passing registers' values as well as PMU state at the time of
PMU interrupt.
* PMU interrupts are taken by hypervisor either as NMIs or regular vector
interrupts for both HVM and PV(H). The interrupts are sent as NMIs to HVM guests
and as virtual interrupts to PV(H) guests
* PV guest's interrupt handler does not read/write PMU MSRs directly. Instead, 
it
accesses xenpmu_data_t and flushes it to HW it before returning.
* PMU mode is controlled at runtime via 
/sys/hypervisor/pmu/pmu/{pmu_mode,pmu_flags}
in addition to 'vpmu' boot option (which is preserved for back compatibility).
The following modes are provided:
  * disable: VPMU is off
  * enable: VPMU is on. Guests can profile themselves, dom0 profiles itself and 
Xen
  * priv_enable: dom0 only profiling. dom0 collects samples for everyone. 
Sampling
    in guests is suspended.
* /proc/xen/xensyms file exports hypervisor's symbols to dom0 (similar to
/proc/kallsyms)
* VPMU infrastructure is now used for HVM, PV and PVH and therefore has been 
moved
up from hvm subtree


Changes in v4:

* Added support for PVH guests:
  o changes in pvpmu_init() to accommodate both PV and PVH guests, still in 
patch 10 
  o more careful use of is_hvm_domain
  o Additional patch (16)
* Moved HVM interrupt handling out of vpmu_do_interrupt() for NMI-safe handling
* Fixed dom0's VCPU selection in privileged mode
* Added a cast in register copy for 32-bit PV guests cpu_user_regs_t in 
vpmu_do_interrupt.
  (don't want to expose compat_cpu_user_regs in a public header)
* Renamed public structures by prefixing them with "xen_"
* Added an entry for xenpf_symdata in xlat.lst
* Fixed pv_cpuid check for vpmu-specific cpuid adjustments
* Varios code style fixes
* Eliminated anonymous unions
* Added more verbiage to NMI patch description


Changes in v3:

* Moved PMU MSR banks out from architectural context data structures to allow
for future expansion without protocol changes
* PMU interrupts can be either NMIs or regular vector interrupts (the latter
is the default)
* Context is now marked as PMU_CACHED by the hypervisor code to avoid certain
race conditions with the guest
* Fixed races with PV guest in MSR access handlers
* More Intel VPMU cleanup
* Moved NMI-unsafe code from NMI handler
* Dropped changes to vcpu->is_running
* Added LVTPC apic handling (cached for PV guests)
* Separated privileged profiling mode into a standalone patch
* Separated NMI handling into a standalone patch


Changes in v2:

* Xen symbols are exported as data structure (as opoosed to a set of formatted
strings in v1). Even though one symbol per hypercall is returned performance
appears to be acceptable: reading whole file from dom0 userland takes on average
about twice as long as reading /proc/kallsyms
* More cleanup of Intel VPMU code to simplify publicly exported structures
* There is an architecture-independent and x86-specific public include files 
(ARM
has a stub)
* General cleanup of public include files to make them more presentable (and
to make auto doc generation better)
* Setting of vcpu->is_running is now done on ARM in schedule_tail as well 
(making
changes to common/schedule.c architecture-independent). Note that this is not
tested since I don't have access to ARM hardware.
* PCPU ID of interrupted processor is now passed to PV guest


Boris Ostrovsky (17):
  common/symbols: Export hypervisor symbols to privileged guest
  x86/VPMU: Stop AMD counters when called from vpmu_save_force()
  x86/VPMU: Minor VPMU cleanup
  intel/VPMU: Clean up Intel VPMU code
  x86/VPMU: Handle APIC_LVTPC accesses
  intel/VPMU: MSR_CORE_PERF_GLOBAL_CTRL should be initialized to zero
  x86/VPMU: Add public xenpmu.h
  x86/VPMU: Make vpmu not HVM-specific
  x86/VPMU: Interface for setting PMU mode and flags
  x86/VPMU: Initialize PMU for PV guests
  x86/VPMU: Add support for PMU register handling on PV guests
  x86/VPMU: Handle PMU interrupts for PV guests
  x86/VPMU: Add privileged PMU mode
  x86/VPMU: Save VPMU state for PV guests during context switch
  x86/VPMU: NMI-based VPMU support
  x86/VPMU: Suport for PVH guests
  x86/VPMU: Move VPMU files up from hvm/ directory

 xen/arch/x86/Makefile                    |   1 +
 xen/arch/x86/domain.c                    |  18 +-
 xen/arch/x86/hvm/Makefile                |   1 -
 xen/arch/x86/hvm/hvm.c                   |   3 +-
 xen/arch/x86/hvm/svm/Makefile            |   1 -
 xen/arch/x86/hvm/svm/vpmu.c              | 494 ----------------
 xen/arch/x86/hvm/vlapic.c                |   5 +-
 xen/arch/x86/hvm/vmx/Makefile            |   1 -
 xen/arch/x86/hvm/vmx/vmcs.c              |  55 ++
 xen/arch/x86/hvm/vmx/vmx.c               |   4 +-
 xen/arch/x86/hvm/vmx/vpmu_core2.c        | 931 ------------------------------
 xen/arch/x86/hvm/vpmu.c                  | 266 ---------
 xen/arch/x86/oprofile/op_model_ppro.c    |   8 +-
 xen/arch/x86/platform_hypercall.c        |  18 +
 xen/arch/x86/traps.c                     |  35 +-
 xen/arch/x86/vpmu.c                      | 671 ++++++++++++++++++++++
 xen/arch/x86/vpmu_amd.c                  | 499 ++++++++++++++++
 xen/arch/x86/vpmu_intel.c                | 936 +++++++++++++++++++++++++++++++
 xen/arch/x86/x86_64/compat/entry.S       |   4 +
 xen/arch/x86/x86_64/entry.S              |   4 +
 xen/arch/x86/x86_64/platform_hypercall.c |   2 +
 xen/common/event_channel.c               |   1 +
 xen/common/symbols.c                     |  50 +-
 xen/common/vsprintf.c                    |   2 +-
 xen/include/asm-x86/domain.h             |   2 +
 xen/include/asm-x86/hvm/vcpu.h           |   3 -
 xen/include/asm-x86/hvm/vmx/vmcs.h       |   4 +-
 xen/include/asm-x86/hvm/vmx/vpmu_core2.h |  51 --
 xen/include/asm-x86/hvm/vpmu.h           | 104 ----
 xen/include/asm-x86/vpmu.h               |  98 ++++
 xen/include/public/arch-x86/xenpmu.h     |  66 +++
 xen/include/public/platform.h            |  19 +
 xen/include/public/xen.h                 |   2 +
 xen/include/public/xenpmu.h              | 102 ++++
 xen/include/xen/hypercall.h              |   4 +
 xen/include/xen/softirq.h                |   1 +
 xen/include/xen/symbols.h                |   7 +-
 xen/include/xlat.lst                     |   1 +
 38 files changed, 2601 insertions(+), 1873 deletions(-)
 delete mode 100644 xen/arch/x86/hvm/svm/vpmu.c
 delete mode 100644 xen/arch/x86/hvm/vmx/vpmu_core2.c
 delete mode 100644 xen/arch/x86/hvm/vpmu.c
 create mode 100644 xen/arch/x86/vpmu.c
 create mode 100644 xen/arch/x86/vpmu_amd.c
 create mode 100644 xen/arch/x86/vpmu_intel.c
 delete mode 100644 xen/include/asm-x86/hvm/vmx/vpmu_core2.h
 delete mode 100644 xen/include/asm-x86/hvm/vpmu.h
 create mode 100644 xen/include/asm-x86/vpmu.h
 create mode 100644 xen/include/public/arch-x86/xenpmu.h
 create mode 100644 xen/include/public/xenpmu.h

-- 
1.8.1.4


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