On 18.02.20 09:44, Christian Borntraeger wrote:
>
>
> On 18.02.20 09:35, David Hildenbrand wrote:
>> On 14.02.20 23:26, Christian Borntraeger wrote:
>>> From: Janosch Frank <frankja@xxxxxxxxxxxxx>
>>>
>>> Save response to sidad and disable address checking for protected
>>> guests.
>>>
>>> Signed-off-by: Janosch Frank <frankja@xxxxxxxxxxxxx>
>>> Reviewed-by: Thomas Huth <thuth@xxxxxxxxxx>
>>> Reviewed-by: Cornelia Huck <cohuck@xxxxxxxxxx>
>>> [borntraeger@xxxxxxxxxx: patch merging, splitting, fixing]
>>> Signed-off-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>
>>> ---
>>> arch/s390/kvm/priv.c | 11 ++++++++---
>>> 1 file changed, 8 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/arch/s390/kvm/priv.c b/arch/s390/kvm/priv.c
>>> index ed52ffa8d5d4..b2de7dc5f58d 100644
>>> --- a/arch/s390/kvm/priv.c
>>> +++ b/arch/s390/kvm/priv.c
>>> @@ -872,7 +872,7 @@ static int handle_stsi(struct kvm_vcpu *vcpu)
>>>
>>> operand2 = kvm_s390_get_base_disp_s(vcpu, &ar);
>>>
>>> - if (operand2 & 0xfff)
>>> + if (!kvm_s390_pv_is_protected(vcpu->kvm) && (operand2 & 0xfff))
>>> return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
>>
>> Why is that needed? I'd assume the hardware handles this for us and this
>> case can never happen for PV? (IOW, change is not necessary)
>
> Hardware is handling this for us AND we are not allowed to inject a specification
> exception. The ultravisor guards the program checks that we are allowed to inject.
>
Yeah, but can this ever trigger without the check? AFAIKs, no. So why
add it?
(rather add a BUG_ON in kvm_s390_inject_program_int() in case we are in
PV mode)
>>
>>>
>>> switch (fc) {
>>> @@ -893,8 +893,13 @@ static int handle_stsi(struct kvm_vcpu *vcpu)
>>> handle_stsi_3_2_2(vcpu, (void *) mem);
>>> break;
>>> }
>>> -
>>> - rc = write_guest(vcpu, operand2, ar, (void *)mem, PAGE_SIZE);
>>> + if (kvm_s390_pv_is_protected(vcpu->kvm)) {
>>> + memcpy((void *)sida_origin(vcpu->arch.sie_block), (void *)mem,
>>> + PAGE_SIZE);
>>> + rc = 0;
>>> + } else {
>>> + rc = write_guest(vcpu, operand2, ar, (void *)mem, PAGE_SIZE);
>>> + }
>>> if (rc) {
>>> rc = kvm_s390_inject_prog_cond(vcpu, rc);
>>> goto out;
>>>
>>
>> I'd pull the interrupt injection into the else case, makes things clearer.
>
> Well, no. Thhe else case could set rc to 0.
Huh?!
if (kvm_s390_pv_is_protected(vcpu->kvm)) {
memcpy((void *)sida_origin(vcpu->arch.sie_block), (void *)mem,
rc = 0;
} else {
rc = write_guest(vcpu, operand2, ar, (void *)mem, PAGE_SIZE);
if (rc) {
rc = kvm_s390_inject_prog_cond(vcpu, rc);
goto out;
}
}
What am I missing?
--
Thanks,
David / dhildenb
