Re: [PATCH RFC 2/5] s390x: implement diag260

From: Christian Borntraeger <borntraeger@de.ibm.com>
To: David Hildenbrand <david@redhat.com>, Cornelia Huck <cohuck@redhat.com>
Cc: Thomas Huth <thuth@redhat.com>,
	Janosch Frank <frankja@linux.ibm.com>,
	"Michael S . Tsirkin" <mst@redhat.com>,
	Heiko Carstens <heiko.carstens@de.ibm.com>,
	qemu-devel@nongnu.org, Halil Pasic <pasic@linux.ibm.com>,
	qemu-s390x@nongnu.org, Claudio Imbrenda <imbrenda@linux.ibm.com>,
	Richard Henderson <rth@twiddle.net>
Subject: Re: [PATCH RFC 2/5] s390x: implement diag260
Date: Mon, 13 Jul 2020 13:54:41 +0200	[thread overview]
Message-ID: <68e4c043-2d4a-f538-1f86-a7171098b0db@de.ibm.com> (raw)
In-Reply-To: <520dafce-917f-9a88-a3ee-c7d614ac113f@redhat.com>

On 10.07.20 10:32, David Hildenbrand wrote:

>>> --- a/target/s390x/misc_helper.c
>>> +++ b/target/s390x/misc_helper.c
>>> @@ -116,6 +116,12 @@ void HELPER(diag)(CPUS390XState *env, uint32_t r1, uint32_t r3, uint32_t num)
>>>      uint64_t r;
>>>  
>>>      switch (num) {
>>> +    case 0x260:
>>> +        qemu_mutex_lock_iothread();
>>> +        handle_diag_260(env, r1, r3, GETPC());
>>> +        qemu_mutex_unlock_iothread();
>>> +        r = 0;
>>> +        break;
>>>      case 0x500:
>>>          /* KVM hypercall */
>>>          qemu_mutex_lock_iothread();
>>
>> Looking at the doc referenced above, it seems that we treat every diag
>> call as privileged under tcg; but it seems that 0x44 isn't? (Unrelated
>> to your patch; maybe I'm misreading.)
> 
> That's also a BUG in kvm then?
> 
> int kvm_s390_handle_diag(struct kvm_vcpu *vcpu)
> {
> ...
> 	if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_PSTATE)
> 		return kvm_s390_inject_program_int(vcpu, PGM_PRIVILEGED_OP);
> ...
> }

diag 44 gives a PRIVOP on LPAR, so I think this is fine. 