On 10/20/26 6:46 AM, Mathieu Poirier wrote:
On Thu, Sep 24, 2026 at 12:12:35PM +0900, Kohei Enju wrote:
On 09/22 10:01, Lorenzo Pieralisi wrote:
On Tue, Sep 15, 2026 at 04:27:21PM -0500, Michael Roth wrote:
On Thu, Sep 03, 2026 at 01:35:50PM -0600, Mathieu Poirier wrote:
From: Jean-Philippe Brucker <[email protected]>
Add a new RmeGuest object, inheriting from ConfidentialGuestSupport, to
support the Arm Realm Management Extension (RME). It is instantiated by
passing on the command-line:
-M virt,confidential-guest-support=<id>
-object rme-guest,id=<id>
This is only the skeleton. Support will be added in following patches.
Signed-off-by: Jean-Philippe Brucker <[email protected]>
Signed-off-by: Mathieu Poirier <[email protected]>
---
docs/system/confidential-guest-support.rst | 1 +
qapi/qom.json | 13 +++++++
target/arm/kvm-rme.c | 42 ++++++++++++++++++++++
target/arm/meson.build | 5 ++-
4 files changed, 60 insertions(+), 1 deletion(-)
create mode 100644 target/arm/kvm-rme.c
diff --git a/docs/system/confidential-guest-support.rst
b/docs/system/confidential-guest-support.rst
index 562a7c3c2852..abb56923ad13 100644
--- a/docs/system/confidential-guest-support.rst
+++ b/docs/system/confidential-guest-support.rst
@@ -42,5 +42,6 @@ Currently supported confidential guest mechanisms are:
* POWER Protected Execution Facility (PEF) (see
:ref:`power-papr-protected-execution-facility-pef`)
* s390x Protected Virtualization (PV) (see :doc:`s390x/protvirt`)
* AWS Nitro Enclaves (see :doc:`nitro`)
+* Arm Realm Management Extension (RME)
Other mechanisms may be supported in future.
diff --git a/qapi/qom.json b/qapi/qom.json
index 776b13027fd8..52997c29a32d 100644
--- a/qapi/qom.json
+++ b/qapi/qom.json
@@ -1288,6 +1288,17 @@
'data': { '*pretty': 'bool',
'*close-action': 'MonitorQMPCloseAction' } }
+##
+# @RmeGuestProperties:
+#
+# Properties for rme-guest objects.
+#
+# Since: 11.1
+##
+{ 'struct': 'RmeGuestProperties',
+ 'base': 'ConfidentialGuestSupportProperties',
Just FYI, based on input from Markus I'm planning to drop this
ConfidentialGuestSupportProperties base type from my series
since it's probably only SNP/TDX that need to be able to switch
it on/off, whereas this series appears to use/require it from
the start.
I'm not exactly sure what it will look like for v3 yet, but if you
were based on v2 you'd instead probably just do the following in the
instance_init function for your rme-guest instance:
cgs->allow_convert_in_place = true;
cgs->convert_in_place = true;
rather than exposing it as a cmdline option.
Yep, it won't be an option for CCA Realms anyway since that will be
the baseline.
IIUC, in-place conversion requires RAM backed by a shared/mappable
guest_memfd. If in-place conversion is always enabled for CCA Realms,
could QEMU also select the equivalent of
-object memory-backend-guest-memfd,id=ram0,size=...,share=on
automatically for the default RAM, so that specifying the RAM size with
`-m` is sufficient?
Are you suggesting that on Arm, we completely get rid of
-object memory-backend-guest-memfd,id=ram0,size=$(RAMSIZE),share=on
or simply to get rid of "size=$(RAMSIZE)" in the above because it is redundant
with "-m $(RAMSIZE)"?
Gavin and Michael, what is your take on that suggestion?
I don't think that's what Kohei meant. He actually suggested the memory backend
shall be pinned to memory-backend-guest-memfd and its in-place conversion shall
be enabled when the memory backend isn't explicitly specified by users through
"-object memory-backend-xxxx". For this inexplicit case, where the memory
backend
is determined by '-mem-path', the memory backend is either
TYPE_MEMORY_BACKEND_FILE
or TYPE_MEMORY_BACKEND_RAM. Please refer to create_default_memdev().
I think Kohei's suggestion makes sense. Besides, I think '-mem-path' should be
disallowed for CCA Realms as TYPE_MEMORY_BACKEND_FILE isn't what we want.
Thanks,
Gavin
Thanks,
Mathieu
Thanks,
Kohei
Thanks,
Lorenzo
Thanks,
Mike
+ 'data': {} }
+
##
# @ObjectType:
#
@@ -1346,6 +1357,7 @@
{ 'name': 'pr-manager-helper',
'if': 'CONFIG_LINUX' },
'qtest',
+ 'rme-guest',
'rng-builtin',
'rng-egd',
{ 'name': 'rng-random',
@@ -1427,6 +1439,7 @@
'pr-manager-helper': { 'type': 'PrManagerHelperProperties',
'if': 'CONFIG_LINUX' },
'qtest': 'QtestProperties',
+ 'rme-guest': 'RmeGuestProperties',
'rng-builtin': 'RngProperties',
'rng-egd': 'RngEgdProperties',
'rng-random': { 'type': 'RngRandomProperties',
diff --git a/target/arm/kvm-rme.c b/target/arm/kvm-rme.c
new file mode 100644
index 000000000000..42e1d1e7b859
--- /dev/null
+++ b/target/arm/kvm-rme.c
@@ -0,0 +1,42 @@
+/*
+ * QEMU Arm RME support
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ *
+ * Copyright Linaro 2026
+ */
+
+#include "qemu/osdep.h"
+
+#include "hw/core/boards.h"
+#include "hw/core/cpu.h"
+#include "kvm_arm.h"
+#include "migration/blocker.h"
+#include "qapi/error.h"
+#include "qom/object_interfaces.h"
+#include "system/confidential-guest-support.h"
+#include "system/kvm.h"
+#include "system/runstate.h"
+
+#define TYPE_RME_GUEST "rme-guest"
+OBJECT_DECLARE_SIMPLE_TYPE(RmeGuest, RME_GUEST)
+
+struct RmeGuest {
+ ConfidentialGuestSupport parent_obj;
+};
+
+OBJECT_DEFINE_SIMPLE_TYPE_WITH_INTERFACES(RmeGuest, rme_guest, RME_GUEST,
+ CONFIDENTIAL_GUEST_SUPPORT,
+ { TYPE_USER_CREATABLE }, { })
+
+static void rme_guest_class_init(ObjectClass *oc, const void *data)
+{
+}
+
+static void rme_guest_init(Object *obj)
+{
+}
+
+static void rme_guest_finalize(Object *obj)
+{
+}
diff --git a/target/arm/meson.build b/target/arm/meson.build
index 0369f96b4cc6..9d322a7aad28 100644
--- a/target/arm/meson.build
+++ b/target/arm/meson.build
@@ -31,7 +31,10 @@ arm_common_user_system_ss.add(when: 'TARGET_AARCH64',
if_true: files(
arm_common_system_ss.add(files(
'arm-qmp-cmds.c',
))
-arm_system_ss.add(when: 'CONFIG_KVM', if_true: files('hyp_gdbstub.c', 'kvm.c'))
+arm_system_ss.add(when: 'CONFIG_KVM', if_true: files(
+ 'hyp_gdbstub.c',
+ 'kvm.c',
+ 'kvm-rme.c'))
arm_system_ss.add(when: 'CONFIG_HVF', if_true: files('hyp_gdbstub.c'))
arm_user_ss.add(files('cpu.c'))
--
2.43.0
