On 10/12/2019 14:50, Bharata B Rao wrote:
> On Tue, Dec 10, 2019 at 02:28:51PM +1100, David Gibson wrote:
>> On Mon, Dec 09, 2019 at 12:30:12PM +0530, Bharata B Rao wrote:
>>> A pseries guest can be run as a secure guest on Ultravisor-enabled
>>> POWER platforms. When such a secure guest is reset, we need to
>>> release/reset a few resources both on ultravisor and hypervisor side.
>>> This is achieved by invoking this new ioctl KVM_PPC_SVM_OFF from the
>>> machine reset path.
>>>
>>> As part of this ioctl, the secure guest is essentially transitioned
>>> back to normal mode so that it can reboot like a regular guest and
>>> become secure again.
>>>
>>> This ioctl has no effect when invoked for a normal guest.
>>>
>>> Signed-off-by: Bharata B Rao <bhar...@linux.ibm.com>
>>> ---
>>> hw/ppc/spapr.c | 1 +
>>> target/ppc/kvm.c | 7 +++++++
>>> target/ppc/kvm_ppc.h | 6 ++++++
>>> 3 files changed, 14 insertions(+)
>>>
>>> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
>>> index f11422fc41..4c7ad3400d 100644
>>> --- a/hw/ppc/spapr.c
>>> +++ b/hw/ppc/spapr.c
>>> @@ -1597,6 +1597,7 @@ static void spapr_machine_reset(MachineState *machine)
>>> void *fdt;
>>> int rc;
>>>
>>> + kvmppc_svm_off();
>>
>> If you're going to have this return an error value, you should really
>> check it here.
>
> I could, by spapr_machine_reset() and the callers don't propagate the
> errors up. So may be I could print a warning instead when ioctl fails?
An error here means you cannot restart the machine and should probably
suspend, or try until it is not EBUSY (==all threads have stopped?).
--
Alexey