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

[Heiko Stuebner]

Am Sonntag, 28. November 2021, 14:52:55 CET schrieb liweiwei:
> It uses two PTE bits, but QEMU is sequentially consistent, So it has no 
> effect on QEMU currently.
> 
> Signed-off-by: liweiwei <liweiwei@iscas.ac.cn>
> Signed-off-by: wangjunqiang <wangjunqiang@iscas.ac.cn>

with the Linux svpbmt patchset
Tested-by: Heiko Stuebner <heiko@sntech.de>

Thanks
Heiko

> ---
>  target/riscv/cpu_bits.h   | 4 ++++
>  target/riscv/cpu_helper.c | 9 +++++++--
>  2 files changed, 11 insertions(+), 2 deletions(-)
> 
> diff --git a/target/riscv/cpu_bits.h b/target/riscv/cpu_bits.h
> index 70391424b0..62713ec37a 100644
> --- a/target/riscv/cpu_bits.h
> +++ b/target/riscv/cpu_bits.h
> @@ -473,7 +473,11 @@ 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
> +#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 e68db3e119..94b01bbf78 100644
> --- a/target/riscv/cpu_helper.c
> +++ b/target/riscv/cpu_helper.c
> @@ -588,13 +588,18 @@ restart:
>              return TRANSLATE_FAIL;
>          }
>  
> -        hwaddr ppn = (pte & ~(target_ulong)PTE_N) >> PTE_PPN_SHIFT;
> +        hwaddr ppn = (pte & ~(target_ulong)PTE_ATTR) >> PTE_PPN_SHIFT;
>  
> -        if (!(pte & PTE_V)) {
> +        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;
> +            }
>              base = ppn << PGSHIFT;
>          } else if ((pte & (PTE_R | PTE_W | PTE_X)) == PTE_W) {
>              /* Reserved leaf PTE flags: PTE_W */
>