[Qemu-devel] [PATCH v0] ppc/spapr: Support reboot of secure pseries guest

[Bharata B Rao]

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 <address@hidden>
---
* The ioctl implementation in the kernel can be found as part of this patchset:
  https://www.spinics.net/lists/linux-mm/msg184366.html
* Updated linux-headers/linux/kvm.h here for completeness as the
  definition of KVM_PPC_SVM_OFF isn't yet part of upstream kernel.

 hw/ppc/spapr.c            | 1 +
 linux-headers/linux/kvm.h | 1 +
 target/ppc/kvm.c          | 7 +++++++
 target/ppc/kvm_ppc.h      | 6 ++++++
 4 files changed, 15 insertions(+)

diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index 821f0d4a49..6abf71f159 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -1709,6 +1709,7 @@ static void spapr_machine_reset(MachineState *machine)
     void *fdt;
     int rc;
 
+    kvmppc_svm_off();
     spapr_caps_apply(spapr);
 
     first_ppc_cpu = POWERPC_CPU(first_cpu);
diff --git a/linux-headers/linux/kvm.h b/linux-headers/linux/kvm.h
index c8423e760c..9603fef9bf 100644
--- a/linux-headers/linux/kvm.h
+++ b/linux-headers/linux/kvm.h
@@ -1327,6 +1327,7 @@ struct kvm_s390_ucas_mapping {
 #define KVM_PPC_GET_RMMU_INFO    _IOW(KVMIO,  0xb0, struct kvm_ppc_rmmu_info)
 /* Available with KVM_CAP_PPC_GET_CPU_CHAR */
 #define KVM_PPC_GET_CPU_CHAR     _IOR(KVMIO,  0xb1, struct kvm_ppc_cpu_char)
+#define KVM_PPC_SVM_OFF           _IO(KVMIO, 0xb2)
 
 /* ioctl for vm fd */
 #define KVM_CREATE_DEVICE        _IOWR(KVMIO,  0xe0, struct kvm_create_device)
diff --git a/target/ppc/kvm.c b/target/ppc/kvm.c
index 8a06d3171e..079d83ce6c 100644
--- a/target/ppc/kvm.c
+++ b/target/ppc/kvm.c
@@ -2953,3 +2953,10 @@ 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 98bd7d5da6..0fd80e1100 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