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Re: [PATCH v3 2/2] target/m68k: consolidate physical translation offset
From: |
Laurent Vivier |
Subject: |
Re: [PATCH v3 2/2] target/m68k: consolidate physical translation offset into get_physical_address() |
Date: |
Tue, 30 Jun 2020 23:20:56 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.8.0 |
Le 30/06/2020 à 13:27, Mark Cave-Ayland a écrit :
> Since all callers to get_physical_address() now apply the same page offset to
> the translation result, move the logic into get_physical_address() itself to
> avoid duplication.
>
> Suggested-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
> Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
> ---
> target/m68k/helper.c | 18 +++++++-----------
> 1 file changed, 7 insertions(+), 11 deletions(-)
>
> diff --git a/target/m68k/helper.c b/target/m68k/helper.c
> index 631eab7774..71c2376910 100644
> --- a/target/m68k/helper.c
> +++ b/target/m68k/helper.c
> @@ -643,7 +643,7 @@ static int get_physical_address(CPUM68KState *env, hwaddr
> *physical,
> /* Transparent Translation Register bit */
> env->mmu.mmusr = M68K_MMU_T_040 | M68K_MMU_R_040;
> }
> - *physical = address & TARGET_PAGE_MASK;
> + *physical = address;
> *page_size = TARGET_PAGE_SIZE;
> return 0;
> }
> @@ -771,7 +771,8 @@ static int get_physical_address(CPUM68KState *env, hwaddr
> *physical,
> }
> *page_size = 1 << page_bits;
> page_mask = ~(*page_size - 1);
> - *physical = next & page_mask;
> + address &= TARGET_PAGE_MASK;
I don't think you need TARGET_PAGE_MASK here:
- TARGET_PAGE_MASK is 4096
- page_mask is either 4096 or 8192
> + *physical = (next & page_mask) + (address & (*page_size - 1));
>
> if (access_type & ACCESS_PTEST) {
> env->mmu.mmusr |= next & M68K_MMU_SR_MASK_040;
> @@ -826,8 +827,6 @@ hwaddr m68k_cpu_get_phys_page_debug(CPUState *cs, vaddr
> addr)
> return -1;
> }
>
> - addr &= TARGET_PAGE_MASK;
> - phys_addr += addr & (page_size - 1);
> return phys_addr;
> }
>
> @@ -891,10 +890,8 @@ bool m68k_cpu_tlb_fill(CPUState *cs, vaddr address, int
> size,
> ret = get_physical_address(&cpu->env, &physical, &prot,
> address, access_type, &page_size);
> if (likely(ret == 0)) {
> - address &= TARGET_PAGE_MASK;
> - physical += address & (page_size - 1);
> - tlb_set_page(cs, address, physical,
> - prot, mmu_idx, TARGET_PAGE_SIZE);
> + tlb_set_page(cs, address & TARGET_PAGE_MASK,
> + physical & TARGET_PAGE_MASK, prot, mmu_idx, page_size);
I had a look to tl_set_page() to see how it manages the entry when the
addresses are not aligned to page_size, and it calls
tlb_set_page_with_attrs() where we have a comment:
/* Add a new TLB entry. At most one entry for a given virtual address
* is permitted. Only a single TARGET_PAGE_SIZE region is mapped, the
* supplied size is only used by tlb_flush_page.
...
So I think it's correct to use TARGET_PAGE_MASK and page_size.
Thanks,
Laurent