Re: [PATCH 3/7] xen/p2m: put reference for superpage

[Roger Pau Monné <roger.pau@xxxxxxxxxx>]

On Tue, Apr 23, 2024 at 09:25:28AM +0100, Luca Fancellu wrote:
> From: Penny Zheng <Penny.Zheng@xxxxxxx>
> 
> We are doing foreign memory mapping for static shared memory, and
> there is a great possibility that it could be super mapped.
> But today, p2m_put_l3_page could not handle superpages.
> 
> This commits implements a new function p2m_put_superpage to handle superpages,
> specifically for helping put extra references for foreign superpages.
> 
> Signed-off-by: Penny Zheng <penny.zheng@xxxxxxx>
> Signed-off-by: Luca Fancellu <luca.fancellu@xxxxxxx>
> ---
> v1:
>  - patch from 
> https://patchwork.kernel.org/project/xen-devel/patch/20231206090623.1932275-9-Penny.Zheng@xxxxxxx/
> ---
>  xen/arch/arm/mmu/p2m.c | 58 +++++++++++++++++++++++++++++++-----------
>  1 file changed, 43 insertions(+), 15 deletions(-)
> 
> diff --git a/xen/arch/arm/mmu/p2m.c b/xen/arch/arm/mmu/p2m.c
> index 41fcca011cf4..479a80fbd4cf 100644
> --- a/xen/arch/arm/mmu/p2m.c
> +++ b/xen/arch/arm/mmu/p2m.c
> @@ -753,17 +753,9 @@ static int p2m_mem_access_radix_set(struct p2m_domain 
> *p2m, gfn_t gfn,
>      return rc;
>  }
>  
> -/*
> - * Put any references on the single 4K page referenced by pte.
> - * TODO: Handle superpages, for now we only take special references for leaf
> - * pages (specifically foreign ones, which can't be super mapped today).
> - */
> -static void p2m_put_l3_page(const lpae_t pte)
> +/* Put any references on the single 4K page referenced by mfn. */
> +static void p2m_put_l3_page(mfn_t mfn, unsigned type)
                                          ^ p2m_type_t?

Roger.