[PATCH v2 ppc-for-5.0 2/2] ppc/spapr: Support reboot of secure pseries guest

[Bharata B Rao <bharata@linux.ibm.com>]

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. If this ioctl
fails for a secure guest, the guest is terminated.

Signed-off-by: Bharata B Rao <bharata@linux.ibm.com>
---
 hw/ppc/spapr.c       | 15 +++++++++++++++
 target/ppc/kvm.c     |  7 +++++++
 target/ppc/kvm_ppc.h |  6 ++++++
 3 files changed, 28 insertions(+)

diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index f11422fc41..25e1a3446e 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -1597,6 +1597,21 @@ static void spapr_machine_reset(MachineState *machine)
     void *fdt;
     int rc;
 
+    /*
+     * KVM_PPC_SVM_OFF ioctl can fail for secure guests, check and
+     * exit in that case. However check for -ENOTTY explicitly
+     * to ensure that we don't terminate normal guests that are
+     * running on kernels which don't support this ioctl.
+     *
+     * Also, this ioctl returns 0 for normal guests on kernels where
+     * this ioctl is supported.
+     */
+    rc = kvmppc_svm_off();
+    if (rc && rc != -ENOTTY) {
+        error_report("Reset of secure guest failed, exiting...");
+        exit(EXIT_FAILURE);
+    }
+
     spapr_caps_apply(spapr);
 
     first_ppc_cpu = POWERPC_CPU(first_cpu);
diff --git a/target/ppc/kvm.c b/target/ppc/kvm.c
index 7406d18945..1a86fa4f0c 100644
--- a/target/ppc/kvm.c
+++ b/target/ppc/kvm.c
@@ -2900,3 +2900,10 @@ void kvmppc_set_reg_tb_offset(PowerPCCPU *cpu, int64_t tb_offset)
         kvm_set_one_reg(cs, KVM_REG_PPC_TB_OFFSET, &tb_offset);
     }
 }
+
+int kvmppc_svm_off(void)
+{
+    KVMState *s = KVM_STATE(current_machine->accelerator);
+
+    return kvm_vm_ioctl(s, KVM_PPC_SVM_OFF);
+}
diff --git a/target/ppc/kvm_ppc.h b/target/ppc/kvm_ppc.h
index 47b08a4030..5cc812e486 100644
--- a/target/ppc/kvm_ppc.h
+++ b/target/ppc/kvm_ppc.h
@@ -37,6 +37,7 @@ int kvmppc_booke_watchdog_enable(PowerPCCPU *cpu);
 target_ulong kvmppc_configure_v3_mmu(PowerPCCPU *cpu,
                                      bool radix, bool gtse,
                                      uint64_t proc_tbl);
+int kvmppc_svm_off(void);
 #ifndef CONFIG_USER_ONLY
 bool kvmppc_spapr_use_multitce(void);
 int kvmppc_spapr_enable_inkernel_multitce(void);
@@ -201,6 +202,11 @@ static inline target_ulong kvmppc_configure_v3_mmu(PowerPCCPU *cpu,
     return 0;
 }
 
+static inline int kvmppc_svm_off(void)
+{
+    return 0;
+}
+
 static inline void kvmppc_set_reg_ppc_online(PowerPCCPU *cpu,
                                              unsigned int online)
 {
-- 
2.21.0