[Xen-devel] [RFC 0/2] xen/arm: vgic: Support 32-bit access for 64-bit register

[Julien Grall <julien.grall@xxxxxxxxxx>]

Hi all,

This series aims to fix the 32-bit access on 64-bit register. Some guest
OS such as FreeBSD and Linux (only in the ITS) use those access and will
crash when starting on Xen.

The first patch introduces generic helpers to read/write/clear/set a register.
While the second is the main purpose of this series.

I'd like to go a bit further in the clean up, hence the RFC. But I wanted them
out in order to help Vijay supporting any access quickly for his ITS series.

TODO:
    - use the new helpers in vGICv2
    - support signed extension generically
    - see what assembly is generated on 32-bit with the uint64_t cast.
    It may be possible to optimize it a bit by avoid uint64_t. Although I'm
    not sure if it's worth it.

Sincerely yours,

Julien Grall (2):
  xen/arm: vgic: Introduce helpers to read/write/clear/set vGIC register
    ...
  xen/arm: vgic-v3: Support 32-bit access for 64-bit registers

 xen/arch/arm/vgic-v3.c     | 126 +++++++++++++++++++++++++++++----------------
 xen/include/asm-arm/vgic.h | 104 +++++++++++++++++++++++++++++++++++++
 2 files changed, 187 insertions(+), 43 deletions(-)

-- 
2.1.4


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