Re: [PATCH v2 2/6] xen/riscv: set A/D bits in Xen's page-table mappings under Svade

[Zhang Zheng <zhangzheng@xxxxxxxxxxx>]

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> The previous patch set A/D bits in case of the Svade extension for G-stage
> mappings. Xen's own S-stage mappings need the same fix as both
> setup_initial_mapping() (the boot page tables) and arch_pmap_map() (the
> fixmap) build leaf PTEs directly instead of going through
> pt_update_entry(), which is what adds A/D bits. So with Svade, both would
> fault on first access.
> 
> Add PTE_ACCESSED to all PAGE_HYPERVISOR_* and also PTE_DIRTY to
> PAGE_HYPERVISOR_RW as it needs to be set during a write to avoid a fault.
> This fixes arch_pmap_map() for free, since it already builds its PTE from
> PAGE_HYPERVISOR_RW. Switch setup_initial_mapping() to use these macros for
> its default, text and rodata permissions, and for the temporary root entry
> built by check_pgtbl_mode_support(), instead of the equivalent raw bit
> lists. The latter drops PTE_WRITABLE, going from RWX to RX, but this is
> harmless, as that entry only has to make the current instruction stream
> fetchable between the two CSR_SATP writes used to probe SATP mode support,
> and nothing writes through it.
> 
> Drop the now-redundant PTE_LEAF_DEFAULT, since converting the last
> open-coded site above leaves it with no user outside page.h itself.
> 
> A PTE is a table entry iff PTE_VALID is set and R/W/X are all clear, so
> update pte_is_table() and pte_is_mapping() accordingly.
> 
> Assisted-by: Claude:claude-opus-5
> Signed-off-by: Baptiste Le Duc <baptiste.le-duc@xxxxxxxxxx>

Tested-by: Zheng Zhang <zhangzheng@xxxxxxxxxxx>

-- 
Zhang Zheng <zhangzheng@xxxxxxxxxxx>