[Xen-devel] [PATCH v2 0/3] x86: improve assisted tlb flush and use it in guest mode

[Roger Pau Monne <roger.pau@xxxxxxxxxx>]

Hello,

The following series aims to improve the TLB flush times when running
nested Xen, and it's specially beneficial when running in shim mode.

Patch #2 is likely the most controversial one, as it changes the
implementation of assisted TLB flushes. I have to admit I haven't been
able to figure out why HVM guest context flushes issued a
flush_tlb_mask, and the commit introducing such behavior doesn't contain
a helpful commit message.

See patch #3 for a comparison on the performance of the L0 assisted
flush vs using x2APIC shorthand.

Thanks, Roger.

Roger Pau Monne (3):
  x86/hvm: allow ASID flush when v != current
  x86/hvm: rework HVMOP_flush_tlbs
  x86/tlb: use Xen L0 assisted TLB flush when available

 xen/arch/x86/guest/hypervisor.c        |  9 +++++
 xen/arch/x86/guest/xen/xen.c           |  6 +++
 xen/arch/x86/hvm/asid.c                |  6 +--
 xen/arch/x86/hvm/hvm.c                 | 54 +++++++++++---------------
 xen/arch/x86/hvm/viridian/viridian.c   |  7 +---
 xen/arch/x86/smp.c                     |  6 +++
 xen/include/asm-x86/guest/hypervisor.h | 13 +++++++
 xen/include/asm-x86/hvm/hvm.h          |  2 +-
 8 files changed, 62 insertions(+), 41 deletions(-)

-- 
2.24.1


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