Re: [PATCH v2] target/mips: Fix PageMask with variable page size

[Aleksandar Markovic <aleksandar.qemu.devel@gmail.com>]

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уторак, 16. јун 2020., Jiaxun Yang <jiaxun.yang@flygoat.com> је написао/ла:

> Our current code assumed the target page size is always 4k
> when handling PageMask and VPN2, however, variable page size
> was just added to mips target and that's nolonger true.
>
> Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
> ---
> v2: Remove Big Page support from this patch
> ---
>  target/mips/cp0_helper.c | 41 ++++++++++++++++++++++++++++------------


Please do not use harcoded numbers, if possibe.

Yours,
Aleksandar



>  target/mips/cpu.h        |  1 +
>  2 files changed, 30 insertions(+), 12 deletions(-)
>
> diff --git a/target/mips/cp0_helper.c b/target/mips/cp0_helper.c
> index bbf12e4a97..f6dc590315 100644
> --- a/target/mips/cp0_helper.c
> +++ b/target/mips/cp0_helper.c
> @@ -872,20 +872,37 @@ void helper_mtc0_memorymapid(CPUMIPSState *env,
> target_ulong arg1)
>      }
>  }
>
> -void update_pagemask(CPUMIPSState *env, target_ulong arg1, int32_t
> *pagemask)
> +void helper_mtc0_pagemask(CPUMIPSState *env, target_ulong arg1)
>  {
> -    uint64_t mask = arg1 >> (TARGET_PAGE_BITS + 1);
> -    if (!(env->insn_flags & ISA_MIPS32R6) || (arg1 == ~0) ||
> -        (mask == 0x0000 || mask == 0x0003 || mask == 0x000F ||
> -         mask == 0x003F || mask == 0x00FF || mask == 0x03FF ||
> -         mask == 0x0FFF || mask == 0x3FFF || mask == 0xFFFF)) {
> -        env->CP0_PageMask = arg1 & (0x1FFFFFFF & (TARGET_PAGE_MASK << 1));
> +    unsigned long mask;
> +    int maskbits;
> +
> +    if (env->insn_flags & ISA_MIPS32R6) {
> +        return;
>      }
> -}
> +    /* Don't care MASKX as we don't support 1KB page */
> +    mask = extract32((uint32_t)arg1, CP0PM_MASK, 16);
> +    maskbits = find_first_zero_bit(&mask, 32);
>
> -void helper_mtc0_pagemask(CPUMIPSState *env, target_ulong arg1)
> -{
> -    update_pagemask(env, arg1, &env->CP0_PageMask);
> +    /* Ensure no more set bit after first zero */
> +    if (mask >> maskbits) {
> +        goto invalid;
> +    }
> +    /* We don't support VTLB entry smaller than target page */
> +    if ((maskbits + 12) < TARGET_PAGE_BITS) {
> +        goto invalid;
> +    }


12.


> +    env->CP0_PageMask = mask << CP0PM_MASK;
> +
> +    return;
> +
> +invalid:
> +    /*
> +     * When invalid, ensure the value is bigger tan or equel to


than or equal


> +     * the minimal but smaller than or equel to the maxium.


equal


> +     */
> +    maskbits = MIN(16, MAX(maskbits, TARGET_PAGE_BITS - 12));
> +    env->CP0_PageMask = ((1 << (16 + 1)) - 1) << CP0PM_MASK;


16, 12, 16 + 1 ?


>  }
>
>  void helper_mtc0_pagegrain(CPUMIPSState *env, target_ulong arg1)
> @@ -1111,7 +1128,7 @@ void helper_mthc0_saar(CPUMIPSState *env,
> target_ulong arg1)
>  void helper_mtc0_entryhi(CPUMIPSState *env, target_ulong arg1)
>  {
>      target_ulong old, val, mask;
> -    mask = (TARGET_PAGE_MASK << 1) | env->CP0_EntryHi_ASID_mask;
> +    mask = ~((1 << 14) - 1) | env->CP0_EntryHi_ASID_mask;


14.


>      if (((env->CP0_Config4 >> CP0C4_IE) & 0x3) >= 2) {
>          mask |= 1 << CP0EnHi_EHINV;
>      }
> diff --git a/target/mips/cpu.h b/target/mips/cpu.h
> index 7cf7f5239f..9c8bb23807 100644
> --- a/target/mips/cpu.h
> +++ b/target/mips/cpu.h
> @@ -618,6 +618,7 @@ struct CPUMIPSState {
>   * CP0 Register 5
>   */
>      int32_t CP0_PageMask;
> +#define CP0PM_MASK 13
>      int32_t CP0_PageGrain_rw_bitmask;
>      int32_t CP0_PageGrain;
>  #define CP0PG_RIE 31
> --
> 2.27.0.rc2
>
>

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