kvm.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: David Gibson <david@gibson.dropbear.id.au>
To: brijesh.singh@amd.com, pair@us.ibm.com, dgilbert@redhat.com,
	pasic@linux.ibm.com, qemu-devel@nongnu.org
Cc: cohuck@redhat.com,
	Richard Henderson <richard.henderson@linaro.org>,
	Marcelo Tosatti <mtosatti@redhat.com>,
	David Hildenbrand <david@redhat.com>,
	borntraeger@de.ibm.com,
	Marcel Apfelbaum <marcel.apfelbaum@gmail.com>,
	Paolo Bonzini <pbonzini@redhat.com>,
	mst@redhat.com, jun.nakajima@intel.com, thuth@redhat.com,
	pragyansri.pathi@intel.com, kvm@vger.kernel.org,
	Eduardo Habkost <ehabkost@redhat.com>,
	qemu-s390x@nongnu.org, qemu-ppc@nongnu.org,
	frankja@linux.ibm.com, Greg Kurz <groug@kaod.org>,
	mdroth@linux.vnet.ibm.com,
	David Gibson <david@gibson.dropbear.id.au>,
	berrange@redhat.com, andi.kleen@intel.com
Subject: [PATCH v7 13/13] s390: Recognize confidential-guest-support option
Date: Thu, 14 Jan 2021 10:58:11 +1100	[thread overview]
Message-ID: <20210113235811.1909610-14-david@gibson.dropbear.id.au> (raw)
In-Reply-To: <20210113235811.1909610-1-david@gibson.dropbear.id.au>

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>
---
 docs/confidential-guest-support.txt |  3 ++
 docs/system/s390x/protvirt.rst      | 19 ++++++---
 hw/s390x/pv.c                       | 62 +++++++++++++++++++++++++++++
 include/hw/s390x/pv.h               |  1 +
 target/s390x/kvm.c                  |  3 ++
 5 files changed, 82 insertions(+), 6 deletions(-)

diff --git a/docs/confidential-guest-support.txt b/docs/confidential-guest-support.txt
index f0801814ff..50b976a082 100644
--- a/docs/confidential-guest-support.txt
+++ b/docs/confidential-guest-support.txt
@@ -43,4 +43,7 @@ AMD Secure Encrypted Virtualization (SEV)
 POWER Protected Execution Facility (PEF)
     docs/papr-pef.txt
 
+s390x Protected Virtualization (PV)
+    docs/system/s390x/protvirt.rst
+
 Other mechanisms may be supported in future.
diff --git a/docs/system/s390x/protvirt.rst b/docs/system/s390x/protvirt.rst
index 712974ad87..0f481043d9 100644
--- a/docs/system/s390x/protvirt.rst
+++ b/docs/system/s390x/protvirt.rst
@@ -22,15 +22,22 @@ If those requirements are met, the capability `KVM_CAP_S390_PROTECTED`
 will indicate that KVM can support PVMs on that LPAR.
 
 
-QEMU Settings
--------------
+Running a Protected Virtual Machine
+-----------------------------------
 
-To indicate to the VM that it can transition into protected mode, the
+To run a PVM you will need to select a CPU model which includes the
 `Unpack facility` (stfle bit 161 represented by the feature
-`unpack`/`S390_FEAT_UNPACK`) needs to be part of the cpu model of
-the VM.
+`unpack`/`S390_FEAT_UNPACK`), and add these options to the command line::
+
+    -object s390-pv-guest,id=pv0 \
+    -machine confidential-guest-support=pv0
+
+Adding these options will:
+
+* Ensure the `unpack` facility is available
+* Enable the IOMMU by default for all I/O devices
+* Initialize the PV mechanism
 
-All I/O devices need to use the IOMMU.
 Passthrough (vfio) devices are currently not supported.
 
 Host huge page backings are not supported. However guests can use huge
diff --git a/hw/s390x/pv.c b/hw/s390x/pv.c
index ab3a2482aa..319d74dfcf 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_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/include/hw/s390x/pv.h b/include/hw/s390x/pv.h
index aee758bc2d..9bbf66f356 100644
--- a/include/hw/s390x/pv.h
+++ b/include/hw/s390x/pv.h
@@ -43,6 +43,7 @@ void s390_pv_prep_reset(void);
 int s390_pv_verify(void);
 void s390_pv_unshare(void);
 void s390_pv_inject_reset_error(CPUState *cs);
+int s390_pv_init(ConfidentialGuestSupport *cgs, Error **errp);
 #else /* CONFIG_KVM */
 static inline bool s390_is_pv(void) { return false; }
 static inline int s390_pv_vm_enable(void) { return 0; }
diff --git a/target/s390x/kvm.c b/target/s390x/kvm.c
index b8385e6b95..d2435664dc 100644
--- a/target/s390x/kvm.c
+++ b/target/s390x/kvm.c
@@ -387,6 +387,9 @@ int kvm_arch_init(MachineState *ms, KVMState *s)
     }
 
     kvm_set_max_memslot_size(KVM_SLOT_MAX_BYTES);
+
+    s390_pv_init(ms->cgs, &error_fatal);
+
     return 0;
 }
 
-- 
2.29.2


  parent reply	other threads:[~2021-01-14  1:53 UTC|newest]

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-13 23:57 [PATCH v7 00/13] Generalize memory encryption models David Gibson
2021-01-13 23:57 ` [PATCH v7 01/13] qom: Allow optional sugar props David Gibson
2021-01-13 23:58 ` [PATCH v7 02/13] confidential guest support: Introduce new confidential guest support class David Gibson
2021-01-14  9:34   ` Daniel P. Berrangé
2021-01-14 10:42     ` David Gibson
2021-01-18 18:51   ` Dr. David Alan Gilbert
2021-01-21  1:06     ` David Gibson
2021-01-21  9:08       ` Dr. David Alan Gilbert
2021-01-29  2:32         ` David Gibson
2021-01-13 23:58 ` [PATCH v7 03/13] sev: Remove false abstraction of flash encryption David Gibson
2021-01-15 12:54   ` Cornelia Huck
2021-01-18  2:59     ` David Gibson
2021-01-13 23:58 ` [PATCH v7 04/13] confidential guest support: Move side effect out of machine_set_memory_encryption() David Gibson
2021-01-15 12:56   ` Cornelia Huck
2021-01-13 23:58 ` [PATCH v7 05/13] confidential guest support: Rework the "memory-encryption" property David Gibson
2021-01-15 13:06   ` Cornelia Huck
2021-01-13 23:58 ` [PATCH v7 06/13] sev: Add Error ** to sev_kvm_init() David Gibson
2021-01-13 23:58 ` [PATCH v7 07/13] confidential guest support: Introduce cgs "ready" flag David Gibson
2021-01-14  8:55   ` Greg Kurz
2021-01-15 13:12   ` Cornelia Huck
2021-01-18 19:47   ` Dr. David Alan Gilbert
2021-01-19  8:16     ` Cornelia Huck
2021-02-02  1:41       ` David Gibson
2021-01-13 23:58 ` [PATCH v7 08/13] confidential guest support: Move SEV initialization into arch specific code David Gibson
2021-01-15 13:24   ` Cornelia Huck
2021-01-18  3:03     ` David Gibson
2021-01-18  8:03       ` Cornelia Huck
2021-01-29  3:12         ` David Gibson
2021-01-13 23:58 ` [PATCH v7 09/13] confidential guest support: Update documentation David Gibson
2021-01-14 10:07   ` Greg Kurz
2021-01-15 15:36   ` Cornelia Huck
2021-01-29  2:36     ` David Gibson
2021-01-13 23:58 ` [PATCH v7 10/13] spapr: Add PEF based confidential guest support David Gibson
2021-01-15 15:41   ` Cornelia Huck
2021-01-29  2:43     ` David Gibson
2021-01-13 23:58 ` [PATCH v7 11/13] spapr: PEF: prevent migration David Gibson
2021-01-13 23:58 ` [PATCH v7 12/13] confidential guest support: Alter virtio default properties for protected guests David Gibson
2021-01-13 23:58 ` David Gibson [this message]
2021-01-14  9:10   ` [PATCH v7 13/13] s390: Recognize confidential-guest-support option Christian Borntraeger
2021-01-14  9:19     ` Christian Borntraeger
2021-01-14  9:24       ` Christian Borntraeger
2021-01-15  0:13         ` David Gibson
2021-01-14 11:45     ` David Gibson
2021-01-15 16:36   ` Cornelia Huck
2021-01-18 17:06     ` Christian Borntraeger

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20210113235811.1909610-14-david@gibson.dropbear.id.au \
    --to=david@gibson.dropbear.id.au \
    --cc=andi.kleen@intel.com \
    --cc=berrange@redhat.com \
    --cc=borntraeger@de.ibm.com \
    --cc=brijesh.singh@amd.com \
    --cc=cohuck@redhat.com \
    --cc=david@redhat.com \
    --cc=dgilbert@redhat.com \
    --cc=ehabkost@redhat.com \
    --cc=frankja@linux.ibm.com \
    --cc=groug@kaod.org \
    --cc=jun.nakajima@intel.com \
    --cc=kvm@vger.kernel.org \
    --cc=marcel.apfelbaum@gmail.com \
    --cc=mdroth@linux.vnet.ibm.com \
    --cc=mst@redhat.com \
    --cc=mtosatti@redhat.com \
    --cc=pair@us.ibm.com \
    --cc=pasic@linux.ibm.com \
    --cc=pbonzini@redhat.com \
    --cc=pragyansri.pathi@intel.com \
    --cc=qemu-devel@nongnu.org \
    --cc=qemu-ppc@nongnu.org \
    --cc=qemu-s390x@nongnu.org \
    --cc=richard.henderson@linaro.org \
    --cc=thuth@redhat.com \
    --subject='Re: [PATCH v7 13/13] s390: Recognize confidential-guest-support option' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).