[v3,0/7] x86: improve assisted tlb flush and use it in guest mode

Message

Roger Pau Monné Jan. 27, 2020, 6:11 p.m. UTC

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.

Only the HAP guest TLB flush is improved, the shadow paging TLB flush is
left as-is, and can be improved later if there's interest.

For a reference on the performance improvement see patch #7, as it's a
huge increase which can benefit other guests using assisted TLB flushes,
and also the ones using the viridian TLB flush assist (ie: Windows).

Thanks, Roger.

Roger Pau Monne (7):
  x86/tlb: fix NEED_FLUSH return type
  x86/hvm: allow ASID flush when v != current
  x86/paging: add TLB flush hooks
  x86/hap: improve hypervisor assisted guest TLB flush
  x86/tlb: introduce a flush guests TLB flag
  x86/tlb: allow disabling the TLB clock
  x86/tlb: use Xen L0 assisted TLB flush when available

 xen/arch/x86/flushtlb.c                | 24 ++++++---
 xen/arch/x86/guest/hypervisor.c        | 10 ++++
 xen/arch/x86/guest/xen/xen.c           |  6 +++
 xen/arch/x86/hvm/asid.c                |  6 +--
 xen/arch/x86/hvm/hvm.c                 | 51 ++----------------
 xen/arch/x86/mm/hap/hap.c              | 48 +++++++++++++++++
 xen/arch/x86/mm/shadow/common.c        | 71 +++++++++++++++++++++++---
 xen/arch/x86/mm/shadow/hvm.c           |  2 +-
 xen/arch/x86/mm/shadow/multi.c         | 17 +++---
 xen/arch/x86/smp.c                     | 11 ++++
 xen/include/asm-x86/flushtlb.h         | 21 +++++++-
 xen/include/asm-x86/guest/hypervisor.h | 17 ++++++
 xen/include/asm-x86/hap.h              |  3 ++
 xen/include/asm-x86/shadow.h           | 12 +++++
 14 files changed, 220 insertions(+), 79 deletions(-)

Comments

Roger Pau Monné Feb. 5, 2020, 4:14 p.m. UTC | #1

Ping?

Just want to make sure this doesn't go under the radar.

Thanks, Roger.

On Mon, Jan 27, 2020 at 07:11:08PM +0100, Roger Pau Monne wrote:
> 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.
> 
> Only the HAP guest TLB flush is improved, the shadow paging TLB flush is
> left as-is, and can be improved later if there's interest.
> 
> For a reference on the performance improvement see patch #7, as it's a
> huge increase which can benefit other guests using assisted TLB flushes,
> and also the ones using the viridian TLB flush assist (ie: Windows).
> 
> Thanks, Roger.
> 
> Roger Pau Monne (7):
>   x86/tlb: fix NEED_FLUSH return type
>   x86/hvm: allow ASID flush when v != current
>   x86/paging: add TLB flush hooks
>   x86/hap: improve hypervisor assisted guest TLB flush
>   x86/tlb: introduce a flush guests TLB flag
>   x86/tlb: allow disabling the TLB clock
>   x86/tlb: use Xen L0 assisted TLB flush when available
> 
>  xen/arch/x86/flushtlb.c                | 24 ++++++---
>  xen/arch/x86/guest/hypervisor.c        | 10 ++++
>  xen/arch/x86/guest/xen/xen.c           |  6 +++
>  xen/arch/x86/hvm/asid.c                |  6 +--
>  xen/arch/x86/hvm/hvm.c                 | 51 ++----------------
>  xen/arch/x86/mm/hap/hap.c              | 48 +++++++++++++++++
>  xen/arch/x86/mm/shadow/common.c        | 71 +++++++++++++++++++++++---
>  xen/arch/x86/mm/shadow/hvm.c           |  2 +-
>  xen/arch/x86/mm/shadow/multi.c         | 17 +++---
>  xen/arch/x86/smp.c                     | 11 ++++
>  xen/include/asm-x86/flushtlb.h         | 21 +++++++-
>  xen/include/asm-x86/guest/hypervisor.h | 17 ++++++
>  xen/include/asm-x86/hap.h              |  3 ++
>  xen/include/asm-x86/shadow.h           | 12 +++++
>  14 files changed, 220 insertions(+), 79 deletions(-)
> 
> -- 
> 2.25.0
>

Jan Beulich Feb. 5, 2020, 4:44 p.m. UTC | #2

On 05.02.2020 17:14, Roger Pau Monné wrote:
> Ping?
> 
> Just want to make sure this doesn't go under the radar.

It's safely sitting in my to-be-looked-at folder, but there's
way too much else to look after to get to it, yet.

Jan