[libvirt] [PATCH 1/3] adding QEMU_CAPS_QUERY_CURRENT_MACHINE and QEMU_CAPS_WAKEUP_SUSPEND_SUPPORT

[Daniel Henrique Barboza]

QEMU commit 46ea94ca9cf ("qmp: query-current-machine with
wakeup-suspend-support") added a new QMP command called
'query-current-machine' that retrieves guest parameters that
can vary in the same machine model (e.g. ACPI support for x86 VMs
depends on the '--no-acpi' option). Currently, this API has a single
flag, 'wakeup-suspend-support', that indicates whether the guest has
the capability of waking up from suspended state.

The original intent of this new API is to avoid situations such as [1],
where an user can execute "virsh dompmsuspend" in a guest that
can't wake up due to lack of support, making the guest unusable.
This is currently the case for any non-x86 arch guests and for
some x86 guests that starts with --no-acpi (q35 machines implements
suspend support even with the --no-acpi flag).

This is the Libvirt side of this API that will be available in
QEMU 4.0. QEMU_CAPS_QUERY_CURRENT_MACHINE is a new
virQEMUCapsCommands that will indicate if the QEMU binary
supports the 'query-current-machine' API. QEMU_CAPS_WAKEUP_SUSPEND_SUPPORT
is a flag that reflects the 'wakeup-suspend-support' value
for the current QEMU instance. In the next patches these
two caps will be populated and used in qemu_driver.c,
'qemuDomainPMSuspendForDuration', to complete the fix
for [1].

[1] https://github.com/open-power-host-os/qemu/issues/31

Signed-off-by: Daniel Henrique Barboza <danielhb413 at gmail.com>
---
 src/qemu/qemu_capabilities.c | 5 +++++
 src/qemu/qemu_capabilities.h | 4 ++++
 2 files changed, 9 insertions(+)

diff --git a/src/qemu/qemu_capabilities.c b/src/qemu/qemu_capabilities.c
index 56228e7a36..318198cbdd 100644
--- a/src/qemu/qemu_capabilities.c
+++ b/src/qemu/qemu_capabilities.c
@@ -523,6 +523,10 @@ VIR_ENUM_IMPL(virQEMUCaps, QEMU_CAPS_LAST,
               "nvdimm.unarmed",
               "scsi-disk.device_id",
               "virtio-pci-non-transitional",
+              "query-current-machine",
+
+              /* 330 */
+              "wakeup-suspend-support",
     );
 
 
@@ -978,6 +982,7 @@ struct virQEMUCapsStringFlags virQEMUCapsCommands[] = {
     { "query-cpus-fast", QEMU_CAPS_QUERY_CPUS_FAST },
     { "qom-list-properties", QEMU_CAPS_QOM_LIST_PROPERTIES },
     { "blockdev-del", QEMU_CAPS_BLOCKDEV_DEL },
+    { "query-current-machine", QEMU_CAPS_QUERY_CURRENT_MACHINE },
 };
 
 struct virQEMUCapsStringFlags virQEMUCapsMigration[] = {
diff --git a/src/qemu/qemu_capabilities.h b/src/qemu/qemu_capabilities.h
index 06c7606e2f..633f2690a3 100644
--- a/src/qemu/qemu_capabilities.h
+++ b/src/qemu/qemu_capabilities.h
@@ -506,6 +506,10 @@ typedef enum { /* virQEMUCapsFlags grouping marker for syntax-check */
     QEMU_CAPS_DEVICE_NVDIMM_UNARMED, /* -device nvdimm,unarmed= */
     QEMU_CAPS_SCSI_DISK_DEVICE_ID, /* 'device_id' property of scsi disk */
     QEMU_CAPS_VIRTIO_PCI_TRANSITIONAL, /* virtio *-pci-{non-}transitional devices */
+    QEMU_CAPS_QUERY_CURRENT_MACHINE, /* query-current-machine command */
+
+    /* 330 */
+    QEMU_CAPS_WAKEUP_SUSPEND_SUPPORT, /* query-current-machine API flag */
 
     QEMU_CAPS_LAST /* this must always be the last item */
 } virQEMUCapsFlags;
-- 
2.20.1