Re: [PATCH v3 8/9] KVM: PPC: Ultravisor: Enter a secure guest

On Thu, Jun 06, 2019 at 02:36:13PM -0300, Claudio Carvalho wrote:

From: Sukadev Bhattiprolu <redacted>

To enter a secure guest, we have to go through the ultravisor, therefore
we do a ucall when we are entering a secure guest.

This change is needed for any sort of entry to the secure guest from the
hypervisor, whether it is a return from an hcall, a return from a
hypervisor interrupt, or the first time that a secure guest vCPU is run.

If we are returning from an hcall, the results are already in the
appropriate registers (R3:12), except for R6,7, which need to be
restored before doing the ucall (UV_RETURN).

Have fast_guest_return check the kvm_arch.secure_guest field so that a
new CPU enters UV when started (in response to a RTAS start-cpu call).

Thanks to input from Paul Mackerras, Ram Pai and Mike Anderson.

Signed-off-by: Sukadev Bhattiprolu <redacted>
[Pass SRR1 in r11 for UV_RETURN, fix kvmppc_msr_interrupt to preserve
 the MSR_S bit]
Signed-off-by: Paul Mackerras <redacted>
[Fix UV_RETURN token number and arch.secure_guest check]
Signed-off-by: Ram Pai <redacted>
[Update commit message and ret_to_ultra comment]
Signed-off-by: Claudio Carvalho <redacted>

Acked-by: Paul Mackerras <redacted>

Paul.