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

[Nicholas Piggin]

Excerpts from Fabiano Rosas's message of March 24, 2021 1:53 am:
> Nicholas Piggin <npiggin at gmail.com> 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 <npiggin at gmail.com>
>> ---
> 
> <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.

Ah yes, we still need to use PPC_SLBIA. IH parameter to slbia was only 
added in binutils 2.27 and we support down to 2.23.

Thanks for the fix I'll add it.

Thanks,
Nick