Re: [PATCH v3 20/39] xen/riscv: resolve the faulting guest physical address

[Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>]

On 10/21/26 1:45 PM, Baptiste Le Duc wrote:
> > Recover the guest physical address from htval and stval. On a guest-page
> > fault to hypervisor, htval holds the guest physical address shifted
> > right by 2, so that an address wider than HSXLEN fits, and stval holds
> > the faulting guest virtual address. The shift is done on paddr_t rather
> > than on the raw register: a guest physical address is 34 bits wide on
> > RV32 with Sv32x4, so shifting an XLEN-wide value would drop its top two
> > bits.
> Nit: "The shift" reads as the right shift just described, while what is meant
> is shifting htval back left by 2 to recover the address. Could you say so
> explicitly?
Sure, I'll update it accordingly. Thanks for clarifying!

> Something like:
>
> ````
> Shift htval back left by 2 and take the two low bits from stval. htval
> is first converted to paddr_t, then shifted: a guest physical address is
> 34 bits wide on RV32 with Sv32x4, so shifting the XLEN-wide register
> itself would drop the top two bits.
> ```
>
> Reviewed-by: Baptiste Le Duc <baptiste.le-duc@xxxxxxxxxx>
Thanks.

~ Oleksii