KVM: PPC: Book3S HV: Handle hypercalls correctly when nested

When we are running as a nested hypervisor, we use a hypercall to
enter the guest rather than code in book3s_hv_rmhandlers.S.  This means
that the hypercall handlers listed in hcall_real_table never get called.
There are some hypercalls that are handled there and not in
kvmppc_pseries_do_hcall(), which therefore won't get processed for
a nested guest.

To fix this, we add cases to kvmppc_pseries_do_hcall() to handle those
hypercalls, with the following exceptions:

- The HPT hypercalls (H_ENTER, H_REMOVE, etc.) are not handled because
  we only support radix mode for nested guests.

- H_CEDE has to be handled specially because the cede logic in
  kvmhv_run_single_vcpu assumes that it has been processed by the time
  that kvmhv_p9_guest_entry() returns.  Therefore we put a special
  case for H_CEDE in kvmhv_p9_guest_entry().

For the XICS hypercalls, if real-mode processing is enabled, then the
virtual-mode handlers assume that they are being called only to finish
up the operation.  Therefore we turn off the real-mode flag in the XICS
code when running as a nested hypervisor.

Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

1 files changed, 2 insertions, 1 deletions

diff --git a/arch/powerpc/kvm/book3s_xics.c b/arch/powerpc/kvm/book3s_xics.c
index d9ba1b06d0f5..b0b2bfc2ff51 100644
--- a/arch/powerpc/kvm/book3s_xics.c
+++ b/arch/powerpc/kvm/book3s_xics.c
@@ -1390,7 +1390,8 @@ static int kvmppc_xics_create(struct kvm_device *dev, u32 type)
 	}
 
 #ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
-	if (cpu_has_feature(CPU_FTR_ARCH_206)) {
+	if (cpu_has_feature(CPU_FTR_ARCH_206) &&
+	    cpu_has_feature(CPU_FTR_HVMODE)) {
 		/* Enable real mode support */
 		xics->real_mode = ENABLE_REALMODE;
 		xics->real_mode_dbg = DEBUG_REALMODE;