Re: [PATCH] xen: Introduce cmpxchg64() and guest_cmpxchg64()

[Oleksandr <olekstysh@xxxxxxxxx>]

On 15.08.20 20:21, Julien Grall wrote:

Hi Julien

> From: Julien Grall <jgrall@xxxxxxxxxx>
>
> The IOREQ code is using cmpxchg() with 64-bit value. At the moment, this
> is x86 code, but there is plan to make it common.
>
> To cater 32-bit arch, introduce two new helpers to deal with 64-bit
> cmpxchg.
>
> The Arm 32-bit implementation of cmpxchg64() is based on the __cmpxchg64
> in Linux v5.8 (arch/arm/include/asm/cmpxchg.h).
>
> Signed-off-by: Julien Grall <jgrall@xxxxxxxxxx>
> Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@xxxxxxxx>
> ---
>   xen/include/asm-arm/arm32/cmpxchg.h | 68 +++++++++++++++++++++++++++++
>   xen/include/asm-arm/arm64/cmpxchg.h |  5 +++
>   xen/include/asm-arm/guest_atomics.h | 22 ++++++++++
>   xen/include/asm-x86/guest_atomics.h |  2 +
>   xen/include/asm-x86/x86_64/system.h |  2 +
>   5 files changed, 99 insertions(+)
Thank you for doing this. I have successfully build-tested your patch 
with IOREQ series on Arm32/Arm64 (of course before that I had changed 
cmpxchg to guest_cmpxchg64 in hvm_send_buffered_ioreq()).

--
Regards,

Oleksandr Tyshchenko