Re: [Qemu-devel] [PATCH v2 5/8] cputlb: Fix size operand for tlb_fill on unaligned store

[Philippe Mathieu-Daudé]

On 8/29/19 1:16 AM, Richard Henderson wrote:
> We are currently passing the size of the full write to
> the tlb_fill for the second page.  Instead pass the real
> size of the write to that page.
> 
> This argument is unused within all tlb_fill, except to be
> logged via tracing, so in practice this makes no difference.
> 
> But in a moment we'll need the value of size2 for watchpoints,
> and if we've computed the value we might as well use it.
> 
> Signed-off-by: Richard Henderson <address@hidden>

Reviewed-by: Philippe Mathieu-Daudé <address@hidden>

> ---
>  accel/tcg/cputlb.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/accel/tcg/cputlb.c b/accel/tcg/cputlb.c
> index c9576bebcf..7fb67d2f05 100644
> --- a/accel/tcg/cputlb.c
> +++ b/accel/tcg/cputlb.c
> @@ -1504,6 +1504,8 @@ store_helper(CPUArchState *env, target_ulong addr, 
> uint64_t val,
>          uintptr_t index2;
>          CPUTLBEntry *entry2;
>          target_ulong page2, tlb_addr2;
> +        size_t size2;
> +
>      do_unaligned_access:
>          /*
>           * Ensure the second page is in the TLB.  Note that the first page
> @@ -1511,13 +1513,14 @@ store_helper(CPUArchState *env, target_ulong addr, 
> uint64_t val,
>           * cannot evict the first.
>           */
>          page2 = (addr + size) & TARGET_PAGE_MASK;
> +        size2 = (addr + size) & ~TARGET_PAGE_MASK;
>          index2 = tlb_index(env, mmu_idx, page2);
>          entry2 = tlb_entry(env, mmu_idx, page2);
>          tlb_addr2 = tlb_addr_write(entry2);
>          if (!tlb_hit_page(tlb_addr2, page2)
>              && !victim_tlb_hit(env, mmu_idx, index2, tlb_off,
>                                 page2 & TARGET_PAGE_MASK)) {
> -            tlb_fill(env_cpu(env), page2, size, MMU_DATA_STORE,
> +            tlb_fill(env_cpu(env), page2, size2, MMU_DATA_STORE,
>                       mmu_idx, retaddr);
>          }
>  
>