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authorDavid Gibson <david@gibson.dropbear.id.au>2020-07-23 14:36:45 +1000
committerDavid Gibson <david@gibson.dropbear.id.au>2021-02-08 16:57:38 +1100
commit651615d92d244a6dfd7c81ab97bd3369fbe41d06 (patch)
tree411fe2e3ff602f0ee3c20be0dbfaf46c1a28e866 /hw
parent9f88a7a3df11a5aaa6212ea535d40d5f92561683 (diff)
downloadqemu-arm-651615d92d244a6dfd7c81ab97bd3369fbe41d06.tar.gz
s390: Recognize confidential-guest-support option
At least some s390 cpu models support "Protected Virtualization" (PV), a mechanism to protect guests from eavesdropping by a compromised hypervisor. This is similar in function to other mechanisms like AMD's SEV and POWER's PEF, which are controlled by the "confidential-guest-support" machine option. s390 is a slightly special case, because we already supported PV, simply by using a CPU model with the required feature (S390_FEAT_UNPACK). To integrate this with the option used by other platforms, we implement the following compromise: - When the confidential-guest-support option is set, s390 will recognize it, verify that the CPU can support PV (failing if not) and set virtio default options necessary for encrypted or protected guests, as on other platforms. i.e. if confidential-guest-support is set, we will either create a guest capable of entering PV mode, or fail outright. - If confidential-guest-support is not set, guests might still be able to enter PV mode, if the CPU has the right model. This may be a little surprising, but shouldn't actually be harmful. To start a guest supporting Protected Virtualization using the new option use the command line arguments: -object s390-pv-guest,id=pv0 -machine confidential-guest-support=pv0 Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Tested-by: Christian Borntraeger <borntraeger@de.ibm.com> Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Diffstat (limited to 'hw')
-rw-r--r--hw/s390x/pv.c62
-rw-r--r--hw/s390x/s390-virtio-ccw.c3
2 files changed, 65 insertions, 0 deletions
diff --git a/hw/s390x/pv.c b/hw/s390x/pv.c
index ab3a2482aa..93eccfc05d 100644
--- a/hw/s390x/pv.c
+++ b/hw/s390x/pv.c
@@ -14,8 +14,11 @@
#include <linux/kvm.h>
#include "cpu.h"
+#include "qapi/error.h"
#include "qemu/error-report.h"
#include "sysemu/kvm.h"
+#include "qom/object_interfaces.h"
+#include "exec/confidential-guest-support.h"
#include "hw/s390x/ipl.h"
#include "hw/s390x/pv.h"
@@ -111,3 +114,62 @@ void s390_pv_inject_reset_error(CPUState *cs)
/* Report that we are unable to enter protected mode */
env->regs[r1 + 1] = DIAG_308_RC_INVAL_FOR_PV;
}
+
+#define TYPE_S390_PV_GUEST "s390-pv-guest"
+OBJECT_DECLARE_SIMPLE_TYPE(S390PVGuest, S390_PV_GUEST)
+
+/**
+ * S390PVGuest:
+ *
+ * The S390PVGuest object is basically a dummy used to tell the
+ * confidential guest support system to use s390's PV mechanism.
+ *
+ * # $QEMU \
+ * -object s390-pv-guest,id=pv0 \
+ * -machine ...,confidential-guest-support=pv0
+ */
+struct S390PVGuest {
+ ConfidentialGuestSupport parent_obj;
+};
+
+typedef struct S390PVGuestClass S390PVGuestClass;
+
+struct S390PVGuestClass {
+ ConfidentialGuestSupportClass parent_class;
+};
+
+int s390_pv_kvm_init(ConfidentialGuestSupport *cgs, Error **errp)
+{
+ if (!object_dynamic_cast(OBJECT(cgs), TYPE_S390_PV_GUEST)) {
+ return 0;
+ }
+
+ if (!s390_has_feat(S390_FEAT_UNPACK)) {
+ error_setg(errp,
+ "CPU model does not support Protected Virtualization");
+ return -1;
+ }
+
+ cgs->ready = true;
+
+ return 0;
+}
+
+OBJECT_DEFINE_TYPE_WITH_INTERFACES(S390PVGuest,
+ s390_pv_guest,
+ S390_PV_GUEST,
+ CONFIDENTIAL_GUEST_SUPPORT,
+ { TYPE_USER_CREATABLE },
+ { NULL })
+
+static void s390_pv_guest_class_init(ObjectClass *oc, void *data)
+{
+}
+
+static void s390_pv_guest_init(Object *obj)
+{
+}
+
+static void s390_pv_guest_finalize(Object *obj)
+{
+}
diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
index a2d9a79c84..2972b607f3 100644
--- a/hw/s390x/s390-virtio-ccw.c
+++ b/hw/s390x/s390-virtio-ccw.c
@@ -250,6 +250,9 @@ static void ccw_init(MachineState *machine)
/* init CPUs (incl. CPU model) early so s390_has_feature() works */
s390_init_cpus(machine);
+ /* Need CPU model to be determined before we can set up PV */
+ s390_pv_init(machine->cgs, &error_fatal);
+
s390_flic_init();
/* init the SIGP facility */