Re: [PATCH v3 3/3] target/riscv: add support for svpbmt extension

[Weiwei Li <liweiwei@iscas.ac.cn>]

在 2022/1/14 下午9:59, Anup Patel 写道:
> On Fri, Jan 14, 2022 at 7:11 AM Weiwei Li <liweiwei@iscas.ac.cn> wrote:
>> It uses two PTE bits, but otherwise has no effect on QEMU, since QEMU is sequentially consistent and doesn't model PMAs currently
>>
>> Signed-off-by: Weiwei Li <liweiwei@iscas.ac.cn>
>> Signed-off-by: Junqiang Wang <wangjunqiang@iscas.ac.cn>
>> Tested-by: Heiko Stuebner <heiko@sntech.de>
>> ---
>>   target/riscv/cpu.c        | 1 +
>>   target/riscv/cpu.h        | 1 +
>>   target/riscv/cpu_bits.h   | 3 +++
>>   target/riscv/cpu_helper.c | 9 ++++++++-
>>   4 files changed, 13 insertions(+), 1 deletion(-)
>>
>> diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c
>> index 45ac98e06b..4f82bd00a3 100644
>> --- a/target/riscv/cpu.c
>> +++ b/target/riscv/cpu.c
>> @@ -670,6 +670,7 @@ static Property riscv_cpu_properties[] = {
>>
>>       DEFINE_PROP_BOOL("svinval", RISCVCPU, cfg.ext_svinval, false),
>>       DEFINE_PROP_BOOL("svnapot", RISCVCPU, cfg.ext_svnapot, false),
>> +    DEFINE_PROP_BOOL("svpbmt", RISCVCPU, cfg.ext_svpbmt, false),
>>
>>       DEFINE_PROP_BOOL("zba", RISCVCPU, cfg.ext_zba, true),
>>       DEFINE_PROP_BOOL("zbb", RISCVCPU, cfg.ext_zbb, true),
>> diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
>> index c3d1845ca1..53f314c752 100644
>> --- a/target/riscv/cpu.h
>> +++ b/target/riscv/cpu.h
>> @@ -329,6 +329,7 @@ struct RISCVCPU {
>>           bool ext_icsr;
>>           bool ext_svinval;
>>           bool ext_svnapot;
>> +        bool ext_svpbmt;
>>           bool ext_zfh;
>>           bool ext_zfhmin;
>>
>> diff --git a/target/riscv/cpu_bits.h b/target/riscv/cpu_bits.h
>> index bc23e3b523..ee294c1d0b 100644
>> --- a/target/riscv/cpu_bits.h
>> +++ b/target/riscv/cpu_bits.h
>> @@ -486,7 +486,10 @@ typedef enum {
>>   #define PTE_A               0x040 /* Accessed */
>>   #define PTE_D               0x080 /* Dirty */
>>   #define PTE_SOFT            0x300 /* Reserved for Software */
>> +#define PTE_RSVD            0x1FC0000000000000 /* Reserved for future use */
>> +#define PTE_PBMT            0x6000000000000000 /* Page-based memory types */
>>   #define PTE_N               0x8000000000000000 /* NAPOT translation */
>> +#define PTE_ATTR            0xFFC0000000000000 /* All attributes bits */
>>
>>   /* Page table PPN shift amount */
>>   #define PTE_PPN_SHIFT       10
>> diff --git a/target/riscv/cpu_helper.c b/target/riscv/cpu_helper.c
>> index 58ab85bca3..f90766e026 100644
>> --- a/target/riscv/cpu_helper.c
>> +++ b/target/riscv/cpu_helper.c
>> @@ -619,16 +619,23 @@ restart:
>>               return TRANSLATE_FAIL;
>>           }
>>
>> -        hwaddr ppn = (pte & ~(target_ulong)PTE_N) >> PTE_PPN_SHIFT;
>> +        hwaddr ppn = (pte & ~(target_ulong)PTE_ATTR) >> PTE_PPN_SHIFT;
>>
>>           RISCVCPU *cpu = env_archcpu(env);
>>           if (!cpu->cfg.ext_svnapot && (pte & PTE_N)) {
>>               return TRANSLATE_FAIL;
>> +        } else if (!cpu->cfg.ext_svpbmt && (pte & PTE_PBMT)) {
>> +            return TRANSLATE_FAIL;
>> +        } else if (pte & PTE_RSVD) {
>> +            return TRANSLATE_FAIL;
>>           } else if (!(pte & PTE_V)) {
>>               /* Invalid PTE */
>>               return TRANSLATE_FAIL;
>>           } else if (!(pte & (PTE_R | PTE_W | PTE_X))) {
>>               /* Inner PTE, continue walking */
>> +            if (pte & (PTE_D | PTE_A | PTE_U | PTE_N | PTE_PBMT)) {
>> +                return TRANSLATE_FAIL;
>> +            }
> I think you should add a patch before PATCH1 to add following:
>
> if (pte & (PTE_D | PTE_A | PTE_U)) {
>      return TRANSLATE_FAIL;
> }
>
> The current PATCH1 should add PTE_N to the comparison and
> this patch can add PTE_PBMT to the comparison.
OK. I'll update this.
>>               base = ppn << PGSHIFT;
>>           } else if ((pte & (PTE_R | PTE_W | PTE_X)) == PTE_W) {
>>               /* Reserved leaf PTE flags: PTE_W */
>> --
>> 2.17.1
>>
> Apart from the minor comment above, it looks good to me.
>
> Reviewed-by: Anup Patel <anup@brainfault.org>
>
> Regards,
> Anup

Regards,

Weiwei Li