[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [PATCH v6 4/9] xen/riscv: set up fixmap mappings
On Tue, 2024-09-10 at 12:01 +0200, Jan Beulich wrote: > On 02.09.2024 19:01, Oleksii Kurochko wrote: > > Set up fixmap mappings and the L0 page table for fixmap support. > > > > Modify the Page Table Entries (PTEs) directly in arch_pmap_map() > > instead of using set_fixmap() ( which relies on map_pages_to_xen() > > ). > > What do you derive this from? There's no set_fixmap() here, and hence > it's unknown how it is going to be implemented. I derived it from the my code where is set_fixmap() is implemented but agree that in brackets it is better to write "will use map_pages_to_xen()" instead of "which relies on map_pages_to_xen()". > The most you can claim > is that it is expected that it will use map_pages_to_xen(), which in > turn ... > > > This change is necessary because PMAP is used when the domain map > > page infrastructure is not yet initialized so map_pages_to_xen() > > called by set_fixmap() needs to map pages on demand, which then > > calls pmap() again, resulting in a loop. > > ... is only expected to use arch_pmap_map(). it is what is written in the message, isn't it? But I am okay to change this part of the commit message to: {set, clear}_fixmap() is expected to be implemented using map_pages_to_xen(), which, in turn, is only expected to use arch_pmap_map(). > > > @@ -81,6 +82,18 @@ static inline void flush_page_to_ram(unsigned > > long mfn, bool sync_icache) > > BUG_ON("unimplemented"); > > } > > > > +/* Write a pagetable entry. */ > > +static inline void write_pte(pte_t *p, pte_t pte) > > +{ > > + write_atomic(p, pte); > > +} > > + > > +/* Read a pagetable entry. */ > > +static inline pte_t read_pte(pte_t *p) > > const pte_t *? It would be better to make it const. Thanks. ~ Oleksii
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