Re: [Xen-devel] [PATCH RFC v2 0/4] Add mem_access support for PV domains

[Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>]

On Mon, Jul 07, 2014 at 07:50:01PM -0700, Aravindh Puthiyaparambil wrote:
> This patch series adds mem_access support for PV domains. To do this the PV
> domain domain has to be run with shadow paging. A p2m implementation for
> mem_access has been added to track the access permissions. Since special ring
> pages are not created for PV domains, this is done as part of enabling
> mem_access.This page is freed when mem_access is disabled or when the domain
> is destroyed.
> 
> When mem_access is enabled for a PV domain, shadow paging is turned on and all
> the shadows are dropped. In the resulting pagefaults, the entries are created
> with the default access permissions. On future pagefaults, if there is a 
> violation,
> a mem_event is sent to the mem_access listener who will then resolve it.
> 
> The access permissions for individual pages are stored in the shadow_flags 
> field
> in the page_info structure. To get the access permissions for individual 
> pages,
> this field is referenced. To set the access permission of individual pages, 
> the new
> permission is set in the shadow_flags and the shadow for the gmfn is dropped. 
> On the
> resulting fault, the new PTE entry will be created with the new permission. A
> new API has been added to set the default access permissions for PV domains.

In regards to the new ops - you also would need to add the XSM hooks.

I recall that in the past Jan had some questions, but I don't recall
exactly what they were - does this patchset address that?

Thanks!
> 
> Patches are based on top of commit f9cff088.
> 
> Signed-off-by: Aravindh Puthiyaparambil <aravindp@xxxxxxxxx>
> Cc: Jan Beulich <jbeulich@xxxxxxxx>
> Cc: Keir Fraser <keir@xxxxxxx>
> Cc: Tim Deegan <tim@xxxxxxx>
> Cc: Ian Campbell <ian.campbell@xxxxxxxxxx>
> Cc: Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
> Cc: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
> 
>   x86/mm: Shadow and p2m changes for PV mem_access
>   x86/mem_access: mem_access and mem_event changes to support PV domains
>   tools/libxc: Add APIs for PV mem_access
>   tool/xen-access: Add support for PV domains
> 
>  tools/libxc/xc_mem_access.c          |  42 ++++++
>  tools/libxc/xc_mem_event.c           |  23 +++-
>  tools/libxc/xc_private.h             |   9 ++
>  tools/libxc/xenctrl.h                |  28 +++-
>  tools/tests/xen-access/xen-access.c  | 104 +++++++++------
>  xen/arch/x86/domain.c                |  12 ++
>  xen/arch/x86/mm/Makefile             |   2 +-
>  xen/arch/x86/mm/mem_access.c         | 244 
> ++++++++++++++++++++++++++++++++++-
>  xen/arch/x86/mm/mem_event.c          |  62 +++++++--
>  xen/arch/x86/mm/p2m-ma.c             | 148 +++++++++++++++++++++
>  xen/arch/x86/mm/p2m.c                |  52 +++++---
>  xen/arch/x86/mm/paging.c             |   7 +
>  xen/arch/x86/mm/shadow/common.c      |  75 ++++++++++-
>  xen/arch/x86/mm/shadow/multi.c       | 101 ++++++++++++++-
>  xen/arch/x86/mm/shadow/private.h     |   7 +
>  xen/arch/x86/srat.c                  |   1 +
>  xen/arch/x86/usercopy.c              |  12 ++
>  xen/common/page_alloc.c              |   3 +
>  xen/drivers/video/vesa.c             |   1 +
>  xen/include/asm-x86/domain.h         |   9 ++
>  xen/include/asm-x86/mem_access.h     |   3 +
>  xen/include/asm-x86/mm.h             |   1 -
>  xen/include/asm-x86/p2m.h            |  17 +++
>  xen/include/asm-x86/paging.h         |   1 +
>  xen/include/asm-x86/shadow.h         |  15 +++
>  xen/include/asm-x86/x86_64/uaccess.h |   7 +
>  xen/include/public/memory.h          |   3 +
>  27 files changed, 899 insertions(+), 90 deletions(-)
>  create mode 100644 xen/arch/x86/mm/p2m-ma.c
> 
> -- 
> 1.9.1
> 
> 
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