From 1f5f49056d0f140568805d66f33396ed5cd90369 Mon Sep 17 00:00:00 2001 From: Juraj Marcin Date: Wed, 4 Sep 2024 12:37:15 +0200 Subject: [PATCH] virtio-mem: Add support for suspend+wake-up with plugged memory Before, the virtio-mem device would unplug all the memory with any reset of the device, including during the wake-up of the guest from a suspended state. Due to this, the virtio-mem driver in the Linux kernel disallowed suspend-to-ram requests in the guest when the VIRTIO_MEM_F_PERSISTENT_SUSPEND feature is not exposed by QEMU. This patch adds the code to skip the reset on wake-up and exposes theVIRTIO_MEM_F_PERSISTENT_SUSPEND feature to the guest kernel driver when suspending is possible in QEMU (currently only x86). Message-ID: <20240904103722.946194-5-jmarcin@redhat.com> Reviewed-by: David Hildenbrand Signed-off-by: Juraj Marcin Signed-off-by: David Hildenbrand --- hw/virtio/virtio-mem.c | 10 ++++++++++ hw/virtio/virtio-qmp.c | 3 +++ 2 files changed, 13 insertions(+) diff --git a/hw/virtio/virtio-mem.c b/hw/virtio/virtio-mem.c index 484d3a5a54..ae1e81d7ba 100644 --- a/hw/virtio/virtio-mem.c +++ b/hw/virtio/virtio-mem.c @@ -890,6 +890,9 @@ static uint64_t virtio_mem_get_features(VirtIODevice *vdev, uint64_t features, if (vmem->unplugged_inaccessible == ON_OFF_AUTO_ON) { virtio_add_feature(&features, VIRTIO_MEM_F_UNPLUGGED_INACCESSIBLE); } + if (qemu_wakeup_suspend_enabled()) { + virtio_add_feature(&features, VIRTIO_MEM_F_PERSISTENT_SUSPEND); + } return features; } @@ -1848,6 +1851,13 @@ static void virtio_mem_system_reset_hold(Object *obj, ResetType type) { VirtIOMEM *vmem = VIRTIO_MEM(obj); + /* + * When waking up from standby/suspend-to-ram, do not unplug any memory. + */ + if (type == RESET_TYPE_WAKEUP) { + return; + } + /* * During usual resets, we will unplug all memory and shrink the usable * region size. This is, however, not possible in all scenarios. Then, diff --git a/hw/virtio/virtio-qmp.c b/hw/virtio/virtio-qmp.c index 1dd96ed20f..cccc6fe761 100644 --- a/hw/virtio/virtio-qmp.c +++ b/hw/virtio/virtio-qmp.c @@ -450,6 +450,9 @@ static const qmp_virtio_feature_map_t virtio_mem_feature_map[] = { FEATURE_ENTRY(VIRTIO_MEM_F_UNPLUGGED_INACCESSIBLE, \ "VIRTIO_MEM_F_UNPLUGGED_INACCESSIBLE: Unplugged memory cannot be " "accessed"), + FEATURE_ENTRY(VIRTIO_MEM_F_PERSISTENT_SUSPEND, \ + "VIRTIO_MEM_F_PERSISTENT_SUSPND: Plugged memory will remain " + "plugged when suspending+resuming"), { -1, "" } }; #endif