Subject: Re: [PATCH v4 44/46] KVM: PPC: Book3S HV P9: implement hash guest support

From: Fabiano Rosas <[email-masked]>
Date: Tue, 23 Mar 2021 12:53:04 -0300

Nicholas Piggin <[email-masked]> writes:

> Guest entry/exit has to restore and save/clear the SLB, plus several
> other bits to accommodate hash guests in the P9 path.
>
> Radix host, hash guest support is removed from the P7/8 path.
>
> Signed-off-by: Nicholas Piggin <[email-masked]>
> ---

<snip>

> diff --git a/arch/powerpc/kvm/book3s_hv_interrupt.c b/arch/powerpc/kvm/book3s_hv_interrupt.c
> index cd84d2c37632..03fbfef708a8 100644
> --- a/arch/powerpc/kvm/book3s_hv_interrupt.c
> +++ b/arch/powerpc/kvm/book3s_hv_interrupt.c
> @@ -55,6 +55,50 @@ static void __accumulate_time(struct kvm_vcpu *vcpu, struct kvmhv_tb_accumulator
>  #define accumulate_time(vcpu, next) do {} while (0)
>  #endif
>
> +static inline void mfslb(unsigned int idx, u64 *slbee, u64 *slbev)
> +{
> +	asm volatile("slbmfev  %0,%1" : "=r" (*slbev) : "r" (idx));
> +	asm volatile("slbmfee  %0,%1" : "=r" (*slbee) : "r" (idx));
> +}
> +
> +static inline void __mtslb(u64 slbee, u64 slbev)
> +{
> +	asm volatile("slbmte %0,%1" :: "r" (slbev), "r" (slbee));
> +}
> +
> +static inline void mtslb(unsigned int idx, u64 slbee, u64 slbev)
> +{
> +	BUG_ON((slbee & 0xfff) != idx);
> +
> +	__mtslb(slbee, slbev);
> +}
> +
> +static inline void slb_invalidate(unsigned int ih)
> +{
> +	asm volatile("slbia %0" :: "i"(ih));
> +}

Fyi, in my environment the assembler complains:

{standard input}: Assembler messages:                                    
{standard input}:1293: Error: junk at end of line: `6'                             
{standard input}:2138: Error: junk at end of line: `6'                    
make[3]: *** [../scripts/Makefile.build:271:
arch/powerpc/kvm/book3s_hv_interrupt.o] Error 1

This works:

-       asm volatile("slbia %0" :: "i"(ih));
+       asm volatile(PPC_SLBIA(%0) :: "i"(ih));

But I don't know what is going on.