Re: [PATCH v2 2/7] RISC-V: KVM: Add Sv57x4 mode support for G-stage

[Anup Patel]

On Wed, May 4, 2022 at 7:44 AM Atish Patra <atishp@xxxxxxxxxxxxxx> wrote:
>
> On Wed, Apr 20, 2022 at 4:25 AM Anup Patel <apatel@xxxxxxxxxxxxxxxx> wrote:
> >
> > Latest QEMU supports G-stage Sv57x4 mode so this patch extends KVM
> > RISC-V G-stage handling to detect and use Sv57x4 mode when available.
> >
> > Signed-off-by: Anup Patel <apatel@xxxxxxxxxxxxxxxx>
> > ---
> >  arch/riscv/include/asm/csr.h |  1 +
> >  arch/riscv/kvm/main.c        |  3 +++
> >  arch/riscv/kvm/mmu.c         | 11 ++++++++++-
> >  3 files changed, 14 insertions(+), 1 deletion(-)
> >
> > diff --git a/arch/riscv/include/asm/csr.h b/arch/riscv/include/asm/csr.h
> > index e935f27b10fd..cc40521e438b 100644
> > --- a/arch/riscv/include/asm/csr.h
> > +++ b/arch/riscv/include/asm/csr.h
> > @@ -117,6 +117,7 @@
> >  #define HGATP_MODE_SV32X4      _AC(1, UL)
> >  #define HGATP_MODE_SV39X4      _AC(8, UL)
> >  #define HGATP_MODE_SV48X4      _AC(9, UL)
> > +#define HGATP_MODE_SV57X4      _AC(10, UL)
> >
> >  #define HGATP32_MODE_SHIFT     31
> >  #define HGATP32_VMID_SHIFT     22
> > diff --git a/arch/riscv/kvm/main.c b/arch/riscv/kvm/main.c
> > index c374dad82eee..1549205fe5fe 100644
> > --- a/arch/riscv/kvm/main.c
> > +++ b/arch/riscv/kvm/main.c
> > @@ -105,6 +105,9 @@ int kvm_arch_init(void *opaque)
> >         case HGATP_MODE_SV48X4:
> >                 str = "Sv48x4";
> >                 break;
> > +       case HGATP_MODE_SV57X4:
> > +               str = "Sv57x4";
> > +               break;
> >         default:
> >                 return -ENODEV;
> >         }
> > diff --git a/arch/riscv/kvm/mmu.c b/arch/riscv/kvm/mmu.c
> > index dc0520792e31..8823eb32dcde 100644
> > --- a/arch/riscv/kvm/mmu.c
> > +++ b/arch/riscv/kvm/mmu.c
> > @@ -751,14 +751,23 @@ void kvm_riscv_gstage_update_hgatp(struct kvm_vcpu *vcpu)
> >  void kvm_riscv_gstage_mode_detect(void)
> >  {
> >  #ifdef CONFIG_64BIT
> > +       /* Try Sv57x4 G-stage mode */
> > +       csr_write(CSR_HGATP, HGATP_MODE_SV57X4 << HGATP_MODE_SHIFT);
> > +       if ((csr_read(CSR_HGATP) >> HGATP_MODE_SHIFT) == HGATP_MODE_SV57X4) {
> > +               gstage_mode = (HGATP_MODE_SV57X4 << HGATP_MODE_SHIFT);
> > +               gstage_pgd_levels = 5;
> > +               goto skip_sv48x4_test;
> > +       }
> > +
> >         /* Try Sv48x4 G-stage mode */
> >         csr_write(CSR_HGATP, HGATP_MODE_SV48X4 << HGATP_MODE_SHIFT);
> >         if ((csr_read(CSR_HGATP) >> HGATP_MODE_SHIFT) == HGATP_MODE_SV48X4) {
> >                 gstage_mode = (HGATP_MODE_SV48X4 << HGATP_MODE_SHIFT);
> >                 gstage_pgd_levels = 4;
> >         }
> > -       csr_write(CSR_HGATP, 0);
> > +skip_sv48x4_test:
> >
> > +       csr_write(CSR_HGATP, 0);
> >         __kvm_riscv_hfence_gvma_all();
> >  #endif
> >  }
> > --
> > 2.25.1
> >
>
> Reviewed-by: Atish Patra <atishp@xxxxxxxxxxxx>

Queued this patch for 5.19

Thanks,
Anup

>
> --
> Regards,
> Atish