Re: [PATCH v3 3/3] target/riscv: Fix the translation of physical address

[Alexander Richardson]

On Tue, 21 Jul 2020 at 13:43, Zong Li <zong.li@sifive.com> wrote:
>
> The real physical address should add the 12 bits page offset. It also
> causes the PMP wrong checking due to the minimum granularity of PMP is
> 4 byte, but we always get the physical address which is 4KB alignment,
> that means, we always use the start address of the page to check PMP for
> all addresses which in the same page.
>
> Signed-off-by: Zong Li <zong.li@sifive.com>
> ---
>  target/riscv/cpu_helper.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/target/riscv/cpu_helper.c b/target/riscv/cpu_helper.c
> index 75d2ae3434..08b069f0c9 100644
> --- a/target/riscv/cpu_helper.c
> +++ b/target/riscv/cpu_helper.c
> @@ -543,7 +543,8 @@ restart:
>              /* for superpage mappings, make a fake leaf PTE for the TLB's
>                 benefit. */
>              target_ulong vpn = addr >> PGSHIFT;
> -            *physical = (ppn | (vpn & ((1L << ptshift) - 1))) << PGSHIFT;
> +            *physical = ((ppn | (vpn & ((1L << ptshift) - 1))) << PGSHIFT) |
> +                        (addr & ~TARGET_PAGE_MASK);
>
>              /* set permissions on the TLB entry */
>              if ((pte & PTE_R) || ((pte & PTE_X) && mxr)) {
> --
> 2.27.0

I made the same change for our CHERI fork a few months ago but forgot
to send the patch upstream (despite marking the commit as a candidate
for upstreaming). Sorry about the duplicated debugging work!
(https://github.com/CTSRD-CHERI/qemu/commit/61c8e3f2c0fd4965ec3f316146d1751fae673c12)