[PATCH kernel] KVM: PPC: Add MMIO emulation for stdx (store doubleword indexed)

[Benjamin Herrenschmidt]

On Fri, 2017-03-17 at 23:11 +1100, Alexey Kardashevskiy wrote:
> On 17/03/17 19:31, Alexey Kardashevskiy wrote:
> > This adds missing stdx emulation which allow Mellanox driver from
> > recent kernels work when MMIO emulation is enforced in the
> > userspace.
> 
> 
> btw what would its load counterpart? Load Doubleword Indexed - ldx
> RT,RA,RB?

Yes.

Do we also do the more "classic" ld/std ?

Cheers,
Ben.

> 
> > 
> > Signed-off-by: Alexey Kardashevskiy <aik at ozlabs.ru>
> > ---
> >  arch/powerpc/include/asm/ppc-opcode.h | 1 +
> >  arch/powerpc/kvm/emulate_loadstore.c  | 6 ++++++
> >  2 files changed, 7 insertions(+)
> > 
> > diff --git a/arch/powerpc/include/asm/ppc-opcode.h
> > b/arch/powerpc/include/asm/ppc-opcode.h
> > index e7d6d86563ee..ca1bbe49590b 100644
> > --- a/arch/powerpc/include/asm/ppc-opcode.h
> > +++ b/arch/powerpc/include/asm/ppc-opcode.h
> > @@ -92,6 +92,7 @@
> >  #define OP_31_XOP_TRAP_64   68
> >  #define OP_31_XOP_DCBF      86
> >  #define OP_31_XOP_LBZX      87
> > +#define OP_31_XOP_STDX      149
> >  #define OP_31_XOP_STWX      151
> >  #define OP_31_XOP_STBX      215
> >  #define OP_31_XOP_LBZUX     119
> > diff --git a/arch/powerpc/kvm/emulate_loadstore.c
> > b/arch/powerpc/kvm/emulate_loadstore.c
> > index 6d3c0ee1d744..9fdbeb8ea86c 100644
> > --- a/arch/powerpc/kvm/emulate_loadstore.c
> > +++ b/arch/powerpc/kvm/emulate_loadstore.c
> > @@ -82,6 +82,12 @@ int kvmppc_emulate_loadstore(struct kvm_vcpu
> > *vcpu)
> >  			kvmppc_set_gpr(vcpu, ra, vcpu-
> > >arch.vaddr_accessed);
> >  			break;
> >  
> > +		case OP_31_XOP_STDX:
> > +			emulated = kvmppc_handle_store(run, vcpu,
> > +						       kvmppc_get_
> > gpr(vcpu, rs),
> > +							8, 1);
> > +			break;
> > +
> >  		case OP_31_XOP_STWX:
> >  			emulated = kvmppc_handle_store(run, vcpu,
> >  						       kvmppc_get_
> > gpr(vcpu, rs),
> > 
> 
>