On 17.02.20 19:40, Christian Borntraeger wrote:
>
>
> On 17.02.20 15:24, David Hildenbrand wrote:
>> On 14.02.20 23:26, Christian Borntraeger wrote:
>>> From: Janosch Frank <frankja@xxxxxxxxxxxxx>
>>>
>>> STHYI data has to go through the bounce buffer.
>>>
>>> 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/intercept.c | 15 ++++++++++-----
>>> 1 file changed, 10 insertions(+), 5 deletions(-)
>>>
>>> diff --git a/arch/s390/kvm/intercept.c b/arch/s390/kvm/intercept.c
>>> index 1e231058e4b3..cfabeecbb777 100644
>>> --- a/arch/s390/kvm/intercept.c
>>> +++ b/arch/s390/kvm/intercept.c
>>> @@ -392,7 +392,7 @@ int handle_sthyi(struct kvm_vcpu *vcpu)
>>> goto out;
>>> }
>>>
>>> - if (addr & ~PAGE_MASK)
>>> + if (!kvm_s390_pv_is_protected(vcpu->kvm) && (addr & ~PAGE_MASK))
>>> return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
>>>
>>> sctns = (void *)get_zeroed_page(GFP_KERNEL);
>>> @@ -403,10 +403,15 @@ int handle_sthyi(struct kvm_vcpu *vcpu)
>>>
>>> out:
>>> if (!cc) {
>>> - r = write_guest(vcpu, addr, reg2, sctns, PAGE_SIZE);
>>> - if (r) {
>>> - free_page((unsigned long)sctns);
>>> - return kvm_s390_inject_prog_cond(vcpu, r);
>>> + if (kvm_s390_pv_is_protected(vcpu->kvm)) {
>>
>> I have the feeling that we might have to think about proper locking for
>> kvm_s390_pv_is_protected(). We have to make sure there cannot be any
>> races with user space. Smells like a new r/w lock maybe.
>
> I think we can keep that within kvm->lock (for the global changes) and vcpu->mutex.
> All the intercepts only happen within the vcpu run ioctl and that takes the
> vcpu->mutex. See my other patch (with mutex_lock(&vcpu->mutex) and mutex_unlock(&vcpu->mutex)
> around the create/destroy functions). lockdep_assert_help is happy and as long as the
> pv_handle reflects the state of the control block of that CPU we are good.
>
> I pushed out the patch/rfcs to pv_worktree on kvms390.git.
Fine with me!
--
Thanks,
David / dhildenb
