Re: [PATCH V5] target/riscv: Ignore reserved bits in PTE for RV64

[Guo Ren]

Thx, Sincerely

On Thu, Sep 26, 2019 at 6:52 AM Alistair Francis <address@hidden> wrote:
>
> On Wed, Sep 25, 2019 at 5:05 AM <address@hidden> wrote:
> >
> > From: Guo Ren <address@hidden>
> >
> > Highest 10 bits of PTE are reserved in riscv-privileged, ref: [1], so we
> > need to ignore them. They cannot be a part of ppn.
> >
> > 1: The RISC-V Instruction Set Manual, Volume II: Privileged Architecture
> >    4.4 Sv39: Page-Based 39-bit Virtual-Memory System
> >    4.5 Sv48: Page-Based 48-bit Virtual-Memory System
> >
> > Signed-off-by: Guo Ren <address@hidden>
> > Tested-by: Bin Meng <address@hidden>
> > Reviewed-by: Liu Zhiwei <address@hidden>
> > Reviewed-by: Bin Meng <address@hidden>
>
> Reviewed-by: Alistair Francis <address@hidden>
>
> Alistair
>
> > ---
> >  target/riscv/cpu_bits.h   | 7 +++++++
> >  target/riscv/cpu_helper.c | 2 +-
> >  2 files changed, 8 insertions(+), 1 deletion(-)
> >
> >  Changelog V5:
> >   - Update Reviewer and Tester.
> >
> >  Changelog V4:
> >   - Change title to Ignore not Bugfix
> >   - Use PTE_PPN_MASK for RV32 and RV64
> >
> >  Changelog V3:
> >   - Use UUL define for PTE_RESERVED
> >   - Keep ppn >> PTE_PPN_SHIFT
> >
> >  Changelog V2:
> >   - Bugfix pte destroyed cause boot fail
> >   - Change to AND with a mask instead of shifting both directions
> >
> > diff --git a/target/riscv/cpu_bits.h b/target/riscv/cpu_bits.h
> > index e998348..399c2c6 100644
> > --- a/target/riscv/cpu_bits.h
> > +++ b/target/riscv/cpu_bits.h
> > @@ -473,6 +473,13 @@
> >  /* Page table PPN shift amount */
> >  #define PTE_PPN_SHIFT       10
> >
> > +/* Page table PPN mask */
> > +#if defined(TARGET_RISCV32)
> > +#define PTE_PPN_MASK        0xffffffffUL
> > +#elif defined(TARGET_RISCV64)
> > +#define PTE_PPN_MASK        0x3fffffffffffffULL
> > +#endif
> > +
> >  /* Leaf page shift amount */
> >  #define PGSHIFT             12
> >
> > diff --git a/target/riscv/cpu_helper.c b/target/riscv/cpu_helper.c
> > index 87dd6a6..9961b37 100644
> > --- a/target/riscv/cpu_helper.c
> > +++ b/target/riscv/cpu_helper.c
> > @@ -261,7 +261,7 @@ restart:
> >  #elif defined(TARGET_RISCV64)
> >          target_ulong pte = ldq_phys(cs->as, pte_addr);
> >  #endif
> > -        hwaddr ppn = pte >> PTE_PPN_SHIFT;
> > +        hwaddr ppn = (pte & PTE_PPN_MASK) >> PTE_PPN_SHIFT;
> >
> >          if (!(pte & PTE_V)) {
> >              /* Invalid PTE */
> > --
> > 2.7.4
> >



-- 
Best Regards
 Guo Ren

ML: https://lore.kernel.org/linux-csky/