Hi,
> On 1 Apr 2025, at 16:22, Orzel, Michal <michal.or...@amd.com> wrote:
>
>
>
> On 01/04/2025 14:57, Bertrand Marquis wrote:
>>
>>
>> Hi Michal,
>>
>>> On 1 Apr 2025, at 11:09, Michal Orzel <michal.or...@amd.com> wrote:
>>>
>>> There's no benefit in having process_shm_chosen() next to process_shm().
>>> The former is just a helper to pass "/chosen" node to the latter for
>>> hwdom case. Drop process_shm_chosen() and instead use process_shm()
>>> passing NULL as node parameter, which will result in searching for and
>>> using /chosen to find shm node (the DT full path search is done in
>>> process_shm() to avoid expensive lookup if !CONFIG_STATIC_SHM). This
>>> will simplify future handling of hw/control domain separation.
>>>
>>> Signed-off-by: Michal Orzel <michal.or...@amd.com>
>>> ---
>>> xen/arch/arm/domain_build.c | 2 +-
>>> xen/arch/arm/include/asm/static-shmem.h | 14 --------------
>>> xen/arch/arm/static-shmem.c | 4 ++++
>>> 3 files changed, 5 insertions(+), 15 deletions(-)
>>>
>>> diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
>>> index 2b5b4331834f..7f9e17e1de4d 100644
>>> --- a/xen/arch/arm/domain_build.c
>>> +++ b/xen/arch/arm/domain_build.c
>>> @@ -2325,7 +2325,7 @@ int __init construct_hwdom(struct kernel_info *kinfo)
>>> else
>>> allocate_memory(d, kinfo);
>>>
>>> - rc = process_shm_chosen(d, kinfo);
>>> + rc = process_shm(d, kinfo, NULL);
>>> if ( rc < 0 )
>>> return rc;
>>>
>>> diff --git a/xen/arch/arm/include/asm/static-shmem.h
>>> b/xen/arch/arm/include/asm/static-shmem.h
>>> index fd0867c4f26b..94eaa9d500f9 100644
>>> --- a/xen/arch/arm/include/asm/static-shmem.h
>>> +++ b/xen/arch/arm/include/asm/static-shmem.h
>>> @@ -18,14 +18,6 @@ int make_resv_memory_node(const struct kernel_info
>>> *kinfo, int addrcells,
>>> int process_shm(struct domain *d, struct kernel_info *kinfo,
>>> const struct dt_device_node *node);
>>>
>>> -static inline int process_shm_chosen(struct domain *d,
>>> - struct kernel_info *kinfo)
>>> -{
>>> - const struct dt_device_node *node = dt_find_node_by_path("/chosen");
>>> -
>>> - return process_shm(d, kinfo, node);
>>> -}
>>> -
>>> int process_shm_node(const void *fdt, int node, uint32_t address_cells,
>>> uint32_t size_cells);
>>>
>>> @@ -74,12 +66,6 @@ static inline int process_shm(struct domain *d, struct
>>> kernel_info *kinfo,
>>> return 0;
>>> }
>>>
>>> -static inline int process_shm_chosen(struct domain *d,
>>> - struct kernel_info *kinfo)
>>> -{
>>> - return 0;
>>> -}
>>> -
>>> static inline void init_sharedmem_pages(void) {};
>>>
>>> static inline int remove_shm_from_rangeset(const struct kernel_info *kinfo,
>>> diff --git a/xen/arch/arm/static-shmem.c b/xen/arch/arm/static-shmem.c
>>> index c74fa13d4847..cda90105923d 100644
>>> --- a/xen/arch/arm/static-shmem.c
>>> +++ b/xen/arch/arm/static-shmem.c
>>> @@ -297,6 +297,10 @@ int __init process_shm(struct domain *d, struct
>>> kernel_info *kinfo,
>>> {
>>> struct dt_device_node *shm_node;
>>>
>>> + /* Hwdom case - shm node under /chosen */
>>> + if ( !node )
>>> + node = dt_find_node_by_path("/chosen");
>>> +
>>
>> I would have 2 questions here:
>> - what if a NULL pointer is passed, wouldn't you wrongly look in the main
>> device tree ?
> Do you mean from hwdom or domU path? In the former it is expected. In the
> latter
> it would be a bug given that there are several dozens of things that operate
> on
> this node being a /chosen/domU@X node before we pass node to process_shm().
>
>> - isn't there a NULL case to be handled if dt_find_node_by_path does not
>> find a result ?
> It wasn't validated before this change. It would be catched in early boot code
> so no worries.
Then an ASSERT on NULL would be good.
>
>>
>> Couldn't the condition also check for the domain to be the hwdom ?
> I could although we have so many /chosen and hwdom asserts in the tree in the
> dom0 creation that I find it not necessary.
There are never to many asserts but ok :-)
With an ASSERT added for the NULL case you can add my R-b.
Cheers
Bertrand
>
> ~Michal
