[PATCH v9 00/10] Hyper-V: paravirtualized remote TLB flushing and hypercall improvements

From: Vitaly Kuznetsov
Date: Fri Jul 14 2017 - 08:44:52 EST

It seems the series missed 4.13 merge window, rebase and resend.

Changes since v8:
- Rebase to the current char-misc tree (mostly to account for the newly
added struct flush_tlb_info in tlb flush interfaces).
- PATCH07: drop hv_tmpcpumap as we have global infrastructure now.
- PATCH08: make fill_gva_list() return 'gva_n - offset' as we were doing
too many REPs before (offset is the size of variable header, we don't
need to include it in REP count when doing hypercall).
- PATCH08/09: add setup_clear_cpu_cap(X86_FEATURE_PCID) to future proof
the code if PCID feature appears in Hyper-V guests.
- Add Andy's/Stephen's Reviewed-by: to all patches (hopefully they stand
with the above mentioned changes).

P.S. I'm traveling next two weeks, my responses will probably be delayed.

Original description:

Hyper-V supports hypercalls for doing local and remote TLB flushing and
gives its guests hints when using hypercall is preferred. While doing
hypercalls for local TLB flushes is probably not practical (and is not
being suggested by modern Hyper-V versions) remote TLB flush with a
hypercall brings significant improvement.

To test the series I wrote a special 'TLB trasher': on a 16 vCPU guest I
was creating 32 threads which were doing 100000 mmap/munmaps each on some
big file. Here are the results:

# time ./pthread_mmap ./randfile
real 3m33.118s
user 0m3.698s
sys 3m16.624s

# time ./pthread_mmap ./randfile
real 2m19.920s
user 0m2.662s
sys 2m9.948s

This series brings a number of small improvements along the way: fast
hypercall implementation and using it for event signaling, rep hypercalls
implementation, hyperv tracing subsystem (which only traces the newly added
remote TLB flush for now).

Vitaly Kuznetsov (10):
x86/hyper-v: include hyperv/ only when CONFIG_HYPERV is set
x86/hyper-v: stash the max number of virtual/logical processor
x86/hyper-v: make hv_do_hypercall() inline
x86/hyper-v: fast hypercall implementation
hyper-v: use fast hypercall for HVCALL_SIGNAL_EVENT
x86/hyper-v: implement rep hypercalls
hyper-v: globalize vp_index
x86/hyper-v: use hypercall for remote TLB flush
x86/hyper-v: support extended CPU ranges for TLB flush hypercalls
tracing/hyper-v: trace hyperv_mmu_flush_tlb_others()

arch/x86/Kbuild | 2 +-
arch/x86/hyperv/Makefile | 2 +-
arch/x86/hyperv/hv_init.c | 90 ++++++------
arch/x86/hyperv/mmu.c | 270 ++++++++++++++++++++++++++++++++++++
arch/x86/include/asm/mshyperv.h | 148 +++++++++++++++++++-
arch/x86/include/asm/trace/hyperv.h | 40 ++++++
arch/x86/include/uapi/asm/hyperv.h | 17 +++
arch/x86/kernel/cpu/mshyperv.c | 13 +-
drivers/hv/channel_mgmt.c | 20 +--
drivers/hv/connection.c | 7 +-
drivers/hv/hv.c | 9 --
drivers/hv/hyperv_vmbus.h | 11 --
drivers/hv/vmbus_drv.c | 17 ---
drivers/pci/host/pci-hyperv.c | 54 +-------
include/linux/hyperv.h | 17 +--
16 files changed, 541 insertions(+), 177 deletions(-)
create mode 100644 arch/x86/hyperv/mmu.c
create mode 100644 arch/x86/include/asm/trace/hyperv.h