[PATCH v3 14/41] KVM: PPC: Book3S 64: move bad_host_intr check to HV handler

[Nicholas Piggin]

Excerpts from Alexey Kardashevskiy's message of March 20, 2021 7:07 pm:
> 
> 
> On 06/03/2021 02:06, Nicholas Piggin wrote:
>> This is not used by PR KVM.
>> 
>> Signed-off-by: Nicholas Piggin <npiggin at gmail.com>
> 
> 
> Reviewed-by: Alexey Kardashevskiy <aik at ozlabs.ru>
> 
> a small tote - it probably makes sense to move this before 09/41 as this 
> one removes what 09/41 added to book3s_64_entry.S. Thanks,

Thanks.

I do realise there's a bit of shuffling around in this part of the 
series, I'm trying to see if that can be improved a bit. But 9/41
is just moving the code without change which I prefer to do first.
This one changes the calling convention for PR which I think is
better to do after we have the entry point in a common file.

Thanks,
Nick


> 
> 
>> ---
>>   arch/powerpc/kvm/book3s_64_entry.S      | 3 ---
>>   arch/powerpc/kvm/book3s_hv_rmhandlers.S | 4 +++-
>>   arch/powerpc/kvm/book3s_segment.S       | 7 +++++++
>>   3 files changed, 10 insertions(+), 4 deletions(-)
>> 
>> diff --git a/arch/powerpc/kvm/book3s_64_entry.S b/arch/powerpc/kvm/book3s_64_entry.S
>> index d06e81842368..7a6b060ceed8 100644
>> --- a/arch/powerpc/kvm/book3s_64_entry.S
>> +++ b/arch/powerpc/kvm/book3s_64_entry.S
>> @@ -78,11 +78,8 @@ do_kvm_interrupt:
>>   	beq-	.Lmaybe_skip
>>   .Lno_skip:
>>   #ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
>> -	cmpwi	r9,KVM_GUEST_MODE_HOST_HV
>> -	beq	kvmppc_bad_host_intr
>>   #ifdef CONFIG_KVM_BOOK3S_PR_POSSIBLE
>>   	cmpwi	r9,KVM_GUEST_MODE_GUEST
>> -	ld	r9,HSTATE_SCRATCH2(r13)
>>   	beq	kvmppc_interrupt_pr
>>   #endif
>>   	b	kvmppc_interrupt_hv
>> diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
>> index f976efb7e4a9..75405ef53238 100644
>> --- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S
>> +++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
>> @@ -1265,6 +1265,7 @@ hdec_soon:
>>   kvmppc_interrupt_hv:
>>   	/*
>>   	 * Register contents:
>> +	 * R9		= HSTATE_IN_GUEST
>>   	 * R12		= (guest CR << 32) | interrupt vector
>>   	 * R13		= PACA
>>   	 * guest R12 saved in shadow VCPU SCRATCH0
>> @@ -1272,6 +1273,8 @@ kvmppc_interrupt_hv:
>>   	 * guest R9 saved in HSTATE_SCRATCH2
>>   	 */
>>   	/* We're now back in the host but in guest MMU context */
>> +	cmpwi	r9,KVM_GUEST_MODE_HOST_HV
>> +	beq	kvmppc_bad_host_intr
>>   	li	r9, KVM_GUEST_MODE_HOST_HV
>>   	stb	r9, HSTATE_IN_GUEST(r13)
>>   
>> @@ -3272,7 +3275,6 @@ END_FTR_SECTION_IFCLR(CPU_FTR_P9_TM_HV_ASSIST)
>>    * cfar is saved in HSTATE_CFAR(r13)
>>    * ppr is saved in HSTATE_PPR(r13)
>>    */
>> -.global kvmppc_bad_host_intr
>>   kvmppc_bad_host_intr:
>>   	/*
>>   	 * Switch to the emergency stack, but start half-way down in
>> diff --git a/arch/powerpc/kvm/book3s_segment.S b/arch/powerpc/kvm/book3s_segment.S
>> index 1f492aa4c8d6..ef1d88b869bf 100644
>> --- a/arch/powerpc/kvm/book3s_segment.S
>> +++ b/arch/powerpc/kvm/book3s_segment.S
>> @@ -167,8 +167,15 @@ kvmppc_interrupt_pr:
>>   	 * R12             = (guest CR << 32) | exit handler id
>>   	 * R13             = PACA
>>   	 * HSTATE.SCRATCH0 = guest R12
>> +	 *
>> +	 * If HV is possible, additionally:
>> +	 * R9              = HSTATE_IN_GUEST
>> +	 * HSTATE.SCRATCH2 = guest R9
>>   	 */
>>   #ifdef CONFIG_PPC64
>> +#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
>> +	ld	r9,HSTATE_SCRATCH2(r13)
>> +#endif
>>   	/* Match 32-bit entry */
>>   	rotldi	r12, r12, 32		  /* Flip R12 halves for stw */
>>   	stw	r12, HSTATE_SCRATCH1(r13) /* CR is now in the low half */
>> 
> 
> -- 
> Alexey
>