Re: [PATCH 00/16] Remove the direct map

[Wei Liu <wl@xxxxxxx>]

On Thu, Apr 30, 2020 at 09:44:09PM +0100, Hongyan Xia wrote:
> From: Hongyan Xia <hongyxia@xxxxxxxxxx>
> 
> This series depends on Xen page table domheap conversion:
> https://lists.xenproject.org/archives/html/xen-devel/2020-04/msg01374.html.
> 
> After breaking the reliance on the direct map to manipulate Xen page
> tables, we can now finally remove the direct map altogether.
> 
> This series:
> - fixes many places that use the direct map incorrectly or assume the
>   presence of an always-mapped direct map in a wrong way.
> - includes the early vmap patches for global mappings.
> - initialises the mapcache for all domains, disables the fast path that
>   uses the direct map for mappings.
> - maps and unmaps xenheap on-demand.
> - adds a boot command line switch to enable or disable the direct map.
> 
> This previous version was in RFC state and can be found here:
> https://lists.xenproject.org/archives/html/xen-devel/2019-09/msg02647.html,
> which has since been broken into small series.

OOI have you done any performance measurements?

Seeing that now even guest table needs mapping / unmapping during
restore, I'm curious to know how that would impact performance.

Wei.

> 
> Hongyan Xia (12):
>   acpi: vmap pages in acpi_os_alloc_memory
>   x86/numa: vmap the pages for memnodemap
>   x86/srat: vmap the pages for acpi_slit
>   x86: map/unmap pages in restore_all_guests.
>   x86/pv: rewrite how building PV dom0 handles domheap mappings
>   x86/mapcache: initialise the mapcache for the idle domain
>   x86: add a boot option to enable and disable the direct map
>   x86/domain_page: remove the fast paths when mfn is not in the
>     directmap
>   xen/page_alloc: add a path for xenheap when there is no direct map
>   x86/setup: leave early boot slightly earlier
>   x86/setup: vmap heap nodes when they are outside the direct map
>   x86/setup: do not create valid mappings when directmap=no
> 
> Wei Liu (4):
>   x86/setup: move vm_init() before acpi calls
>   x86/pv: domheap pages should be mapped while relocating initrd
>   x86: add Persistent Map (PMAP) infrastructure
>   x86: lift mapcache variable to the arch level
> 
>  docs/misc/xen-command-line.pandoc |  12 +++
>  xen/arch/arm/setup.c              |   4 +-
>  xen/arch/x86/Makefile             |   1 +
>  xen/arch/x86/domain.c             |   4 +-
>  xen/arch/x86/domain_page.c        |  53 ++++++++-----
>  xen/arch/x86/mm.c                 |   8 +-
>  xen/arch/x86/numa.c               |   8 +-
>  xen/arch/x86/pmap.c               |  87 +++++++++++++++++++++
>  xen/arch/x86/pv/dom0_build.c      |  75 ++++++++++++++----
>  xen/arch/x86/setup.c              | 125 +++++++++++++++++++++++++-----
>  xen/arch/x86/srat.c               |   3 +-
>  xen/arch/x86/x86_64/entry.S       |  27 ++++++-
>  xen/common/page_alloc.c           |  85 +++++++++++++++++---
>  xen/common/vmap.c                 |  37 +++++++--
>  xen/drivers/acpi/osl.c            |   9 ++-
>  xen/include/asm-arm/mm.h          |   5 ++
>  xen/include/asm-x86/domain.h      |  12 +--
>  xen/include/asm-x86/fixmap.h      |   3 +
>  xen/include/asm-x86/mm.h          |  17 +++-
>  xen/include/asm-x86/pmap.h        |  10 +++
>  xen/include/xen/vmap.h            |   5 ++
>  21 files changed, 495 insertions(+), 95 deletions(-)
>  create mode 100644 xen/arch/x86/pmap.c
>  create mode 100644 xen/include/asm-x86/pmap.h
> 
> -- 
> 2.24.1.AMZN
>