spapr: Add PEF based confidential guest support

Some upcoming POWER machines have a system called PEF (Protected
Execution Facility) which uses a small ultravisor to allow guests to
run in a way that they can't be eavesdropped by the hypervisor.  The
effect is roughly similar to AMD SEV, although the mechanisms are
quite different.

Most of the work of this is done between the guest, KVM and the
ultravisor, with little need for involvement by qemu.  However qemu
does need to tell KVM to allow secure VMs.

Because the availability of secure mode is a guest visible difference
which depends on having the right hardware and firmware, we don't
enable this by default.  In order to run a secure guest you need to
create a "pef-guest" object and set the confidential-guest-support
property to point to it.

Note that this just *allows* secure guests, the architecture of PEF is
such that the guest still needs to talk to the ultravisor to enter
secure mode.  Qemu has no direct way of knowing if the guest is in
secure mode, and certainly can't know until well after machine
creation time.

To start a PEF-capable guest, use the command line options:
    -object pef-guest,id=pef0 -machine confidential-guest-support=pef0

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Greg Kurz <groug@kaod.org>

2 files changed, 0 insertions, 24 deletions

diff --git a/target/ppc/kvm.c b/target/ppc/kvm.c
index daf690a..0c5056d 100644
--- a/target/ppc/kvm.c
+++ b/target/ppc/kvm.c
@@ -2929,21 +2929,3 @@ void kvmppc_set_reg_tb_offset(PowerPCCPU *cpu, int64_t tb_offset)
         kvm_set_one_reg(cs, KVM_REG_PPC_TB_OFFSET, &tb_offset);
     }
 }
-
-/*
- * Don't set error if KVM_PPC_SVM_OFF ioctl is invoked on kernels
- * that don't support this ioctl.
- */
-void kvmppc_svm_off(Error **errp)
-{
-    int rc;
-
-    if (!kvm_enabled()) {
-        return;
-    }
-
-    rc = kvm_vm_ioctl(KVM_STATE(current_accel()), KVM_PPC_SVM_OFF);
-    if (rc && rc != -ENOTTY) {
-        error_setg_errno(errp, -rc, "KVM_PPC_SVM_OFF ioctl failed");
-    }
-}
diff --git a/target/ppc/kvm_ppc.h b/target/ppc/kvm_ppc.h
index 73ce2bc..989f61a 100644
--- a/target/ppc/kvm_ppc.h
+++ b/target/ppc/kvm_ppc.h
@@ -39,7 +39,6 @@ int kvmppc_booke_watchdog_enable(PowerPCCPU *cpu);
 target_ulong kvmppc_configure_v3_mmu(PowerPCCPU *cpu,
                                      bool radix, bool gtse,
                                      uint64_t proc_tbl);
-void kvmppc_svm_off(Error **errp);
 #ifndef CONFIG_USER_ONLY
 bool kvmppc_spapr_use_multitce(void);
 int kvmppc_spapr_enable_inkernel_multitce(void);
@@ -216,11 +215,6 @@ static inline target_ulong kvmppc_configure_v3_mmu(PowerPCCPU *cpu,
     return 0;
 }
 
-static inline void kvmppc_svm_off(Error **errp)
-{
-    return;
-}
-
 static inline void kvmppc_set_reg_ppc_online(PowerPCCPU *cpu,
                                              unsigned int online)
 {