--- /dev/null
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Stefan Hajnoczi <stefanha@redhat.com>
+Date: Wed, 10 Jul 2019 16:14:40 +0200
+Subject: [PATCH] virtio-balloon: fix QEMU 4.0 config size migration
+ incompatibility
+
+The virtio-balloon config size changed in QEMU 4.0 even for existing
+machine types. Migration from QEMU 3.1 to 4.0 can fail in some
+circumstances with the following error:
+
+ qemu-system-x86_64: get_pci_config_device: Bad config data: i=0x10 read: a1 device: 1 cmask: ff wmask: c0 w1cmask:0
+
+This happens because the virtio-balloon config size affects the VIRTIO
+Legacy I/O Memory PCI BAR size.
+
+Introduce a qdev property called "qemu-4-0-config-size" and enable it
+only for the QEMU 4.0 machine types. This way <4.0 machine types use
+the old size, 4.0 uses the larger size, and >4.0 machine types use the
+appropriate size depending on enabled virtio-balloon features.
+
+Live migration to and from old QEMUs to QEMU 4.1 works again as long as
+a versioned machine type is specified (do not use just "pc"!).
+
+Originally-by: Wolfgang Bumiller <w.bumiller@proxmox.com>
+Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
+Signed-off-by: Wolfgang Bumiller <w.bumiller@proxmox.com>
+---
+ hw/core/machine.c | 1 +
+ hw/virtio/virtio-balloon.c | 28 +++++++++++++++++++++++++---
+ include/hw/virtio/virtio-balloon.h | 2 ++
+ 3 files changed, 28 insertions(+), 3 deletions(-)
+
+diff --git a/hw/core/machine.c b/hw/core/machine.c
+index 743fef2898..f25c91875f 100644
+--- a/hw/core/machine.c
++++ b/hw/core/machine.c
+@@ -36,6 +36,7 @@ GlobalProperty hw_compat_3_1[] = {
+ { "usb-kbd", "serial", "42" },
+ { "virtio-blk-device", "discard", "false" },
+ { "virtio-blk-device", "write-zeroes", "false" },
++ { "virtio-balloon-device", "qemu-4-0-config-size", "false" },
+ };
+ const size_t hw_compat_3_1_len = G_N_ELEMENTS(hw_compat_3_1);
+
+diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c
+index d96e4aa96f..c8788ea18d 100644
+--- a/hw/virtio/virtio-balloon.c
++++ b/hw/virtio/virtio-balloon.c
+@@ -615,6 +615,22 @@ virtio_balloon_free_page_report_notify(NotifierWithReturn *n, void *data)
+ return 0;
+ }
+
++static size_t virtio_balloon_config_size(VirtIOBalloon *s)
++{
++ uint64_t features = s->host_features;
++
++ if (s->qemu_4_0_config_size) {
++ return sizeof(struct virtio_balloon_config);
++ }
++ if (virtio_has_feature(features, VIRTIO_BALLOON_F_PAGE_POISON)) {
++ return sizeof(struct virtio_balloon_config);
++ }
++ if (virtio_has_feature(features, VIRTIO_BALLOON_F_FREE_PAGE_HINT)) {
++ return offsetof(struct virtio_balloon_config, poison_val);
++ }
++ return offsetof(struct virtio_balloon_config, free_page_report_cmd_id);
++}
++
+ static void virtio_balloon_get_config(VirtIODevice *vdev, uint8_t *config_data)
+ {
+ VirtIOBalloon *dev = VIRTIO_BALLOON(vdev);
+@@ -635,7 +651,7 @@ static void virtio_balloon_get_config(VirtIODevice *vdev, uint8_t *config_data)
+ }
+
+ trace_virtio_balloon_get_config(config.num_pages, config.actual);
+- memcpy(config_data, &config, sizeof(struct virtio_balloon_config));
++ memcpy(config_data, &config, virtio_balloon_config_size(dev));
+ }
+
+ static int build_dimm_list(Object *obj, void *opaque)
+@@ -679,7 +695,7 @@ static void virtio_balloon_set_config(VirtIODevice *vdev,
+ uint32_t oldactual = dev->actual;
+ ram_addr_t vm_ram_size = get_current_ram_size();
+
+- memcpy(&config, config_data, sizeof(struct virtio_balloon_config));
++ memcpy(&config, config_data, virtio_balloon_config_size(dev));
+ dev->actual = le32_to_cpu(config.actual);
+ if (dev->actual != oldactual) {
+ qapi_event_send_balloon_change(vm_ram_size -
+@@ -795,7 +811,7 @@ static void virtio_balloon_device_realize(DeviceState *dev, Error **errp)
+ int ret;
+
+ virtio_init(vdev, "virtio-balloon", VIRTIO_ID_BALLOON,
+- sizeof(struct virtio_balloon_config));
++ virtio_balloon_config_size(s));
+
+ ret = qemu_add_balloon_handler(virtio_balloon_to_target,
+ virtio_balloon_stat, s);
+@@ -926,6 +942,12 @@ static Property virtio_balloon_properties[] = {
+ VIRTIO_BALLOON_F_DEFLATE_ON_OOM, false),
+ DEFINE_PROP_BIT("free-page-hint", VirtIOBalloon, host_features,
+ VIRTIO_BALLOON_F_FREE_PAGE_HINT, false),
++ /* QEMU 4.0 accidentally changed the config size even when free-page-hint
++ * is disabled, resulting in QEMU 3.1 migration incompatibility. This
++ * property retains this quirk for QEMU 4.1 machine types.
++ */
++ DEFINE_PROP_BOOL("qemu-4-0-config-size", VirtIOBalloon,
++ qemu_4_0_config_size, false),
+ DEFINE_PROP_LINK("iothread", VirtIOBalloon, iothread, TYPE_IOTHREAD,
+ IOThread *),
+ DEFINE_PROP_END_OF_LIST(),
+diff --git a/include/hw/virtio/virtio-balloon.h b/include/hw/virtio/virtio-balloon.h
+index 1afafb12f6..5a99293a45 100644
+--- a/include/hw/virtio/virtio-balloon.h
++++ b/include/hw/virtio/virtio-balloon.h
+@@ -71,6 +71,8 @@ typedef struct VirtIOBalloon {
+ int64_t stats_poll_interval;
+ uint32_t host_features;
+ PartiallyBalloonedPage *pbp;
++
++ bool qemu_4_0_config_size;
+ } VirtIOBalloon;
+
+ #endif
+--
+2.20.1
+
+++ /dev/null
-From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
-From: Wolfgang Bumiller <w.bumiller@proxmox.com>
-Date: Tue, 2 Jul 2019 09:23:43 +0200
-Subject: [PATCH] virtio-balloon: use smaller config on older guests
-
-The increased config size changes its alignment requirements
-preventing guests from migrating from old qemu versions if
-their balloon mapping isn't stricter aligned.
-So base the default config size on the machine version.
-
-Signed-off-by: Wolfgang Bumiller <w.bumiller@proxmox.com>
----
- hw/i386/pc.c | 2 ++
- hw/virtio/virtio-balloon.c | 52 +++++++++++++++++++++++++++---
- include/hw/virtio/virtio-balloon.h | 1 +
- 3 files changed, 51 insertions(+), 4 deletions(-)
-
-diff --git a/hw/i386/pc.c b/hw/i386/pc.c
-index f2c15bf1f2..a6c01203f5 100644
---- a/hw/i386/pc.c
-+++ b/hw/i386/pc.c
-@@ -77,6 +77,7 @@
- #include "hw/i386/intel_iommu.h"
- #include "hw/net/ne2000-isa.h"
- #include "standard-headers/asm-x86/bootparam.h"
-+#include "hw/virtio/virtio-balloon.h"
-
- /* debug PC/ISA interrupts */
- //#define DEBUG_IRQ
-@@ -137,6 +138,7 @@ GlobalProperty pc_compat_3_1[] = {
- { "Icelake-Server" "-" TYPE_X86_CPU, "mpx", "on" },
- { "Cascadelake-Server" "-" TYPE_X86_CPU, "stepping", "5" },
- { TYPE_X86_CPU, "x-intel-pt-auto-level", "off" },
-+ { TYPE_VIRTIO_BALLOON, "x-use-large-balloon-config", "off" },
- };
- const size_t pc_compat_3_1_len = G_N_ELEMENTS(pc_compat_3_1);
-
-diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c
-index 2112874055..d10298786d 100644
---- a/hw/virtio/virtio-balloon.c
-+++ b/hw/virtio/virtio-balloon.c
-@@ -328,6 +328,28 @@ static void balloon_stats_set_poll_interval(Object *obj, Visitor *v,
- balloon_stats_change_timer(s, 0);
- }
-
-+static void balloon_get_large_config(Object *obj, Visitor *v,
-+ const char *name, void *opaque,
-+ Error **errp)
-+{
-+ VirtIOBalloon *s = opaque;
-+ visit_type_bool(v, name, &s->use_large_config, errp);
-+}
-+
-+static void balloon_set_large_config(Object *obj, Visitor *v,
-+ const char *name, void *opaque,
-+ Error **errp)
-+{
-+ VirtIOBalloon *s = opaque;
-+ DeviceState *dev = DEVICE(s);
-+
-+ if (dev->realized) {
-+ error_setg(errp, "balloon config size cannot be changed at runtime");
-+ } else {
-+ visit_type_bool(v, name, &s->use_large_config, errp);
-+ }
-+}
-+
- static void virtio_balloon_handle_output(VirtIODevice *vdev, VirtQueue *vq)
- {
- VirtIOBalloon *s = VIRTIO_BALLOON(vdev);
-@@ -526,6 +548,17 @@ static bool virtio_balloon_free_page_support(void *opaque)
- return virtio_vdev_has_feature(vdev, VIRTIO_BALLOON_F_FREE_PAGE_HINT);
- }
-
-+static size_t virtio_balloon_config_size(void *opaque)
-+{
-+ VirtIOBalloon *s = opaque;
-+
-+ if (s->use_large_config) {
-+ return sizeof(struct virtio_balloon_config);
-+ } else {
-+ return offsetof(struct virtio_balloon_config, free_page_report_cmd_id);
-+ }
-+}
-+
- static void virtio_balloon_free_page_start(VirtIOBalloon *s)
- {
- VirtIODevice *vdev = VIRTIO_DEVICE(s);
-@@ -635,7 +668,7 @@ static void virtio_balloon_get_config(VirtIODevice *vdev, uint8_t *config_data)
- }
-
- trace_virtio_balloon_get_config(config.num_pages, config.actual);
-- memcpy(config_data, &config, sizeof(struct virtio_balloon_config));
-+ memcpy(config_data, &config, virtio_balloon_config_size(dev));
- }
-
- static int build_dimm_list(Object *obj, void *opaque)
-@@ -679,7 +712,7 @@ static void virtio_balloon_set_config(VirtIODevice *vdev,
- uint32_t oldactual = dev->actual;
- ram_addr_t vm_ram_size = get_current_ram_size();
-
-- memcpy(&config, config_data, sizeof(struct virtio_balloon_config));
-+ memcpy(&config, config_data, virtio_balloon_config_size(dev));
- dev->actual = le32_to_cpu(config.actual);
- if (dev->actual != oldactual) {
- qapi_event_send_balloon_change(vm_ram_size -
-@@ -766,7 +799,7 @@ static void virtio_balloon_device_realize(DeviceState *dev, Error **errp)
- int ret;
-
- virtio_init(vdev, "virtio-balloon", VIRTIO_ID_BALLOON,
-- sizeof(struct virtio_balloon_config));
-+ virtio_balloon_config_size(s));
-
- ret = qemu_add_balloon_handler(virtio_balloon_to_target,
- virtio_balloon_stat, s);
-@@ -791,7 +824,7 @@ static void virtio_balloon_device_realize(DeviceState *dev, Error **errp)
- s->free_page_report_notify.notify =
- virtio_balloon_free_page_report_notify;
- precopy_add_notifier(&s->free_page_report_notify);
-- if (s->iothread) {
-+ if (s->iothread && s->use_large_config) {
- object_ref(OBJECT(s->iothread));
- s->free_page_bh = aio_bh_new(iothread_get_aio_context(s->iothread),
- virtio_ballloon_get_free_page_hints, s);
-@@ -804,6 +837,11 @@ static void virtio_balloon_device_realize(DeviceState *dev, Error **errp)
- virtio_error(vdev, "iothread is missing");
- }
- }
-+
-+ if (!s->use_large_config) {
-+ s->host_features &= ~(1 << VIRTIO_BALLOON_F_PAGE_POISON);
-+ }
-+
- reset_stats(s);
- }
-
-@@ -880,6 +918,12 @@ static void virtio_balloon_instance_init(Object *obj)
- balloon_stats_get_poll_interval,
- balloon_stats_set_poll_interval,
- NULL, s, NULL);
-+
-+ s->use_large_config = true;
-+ object_property_add(obj, "x-use-large-balloon-config", "bool",
-+ balloon_get_large_config,
-+ balloon_set_large_config,
-+ NULL, s, NULL);
- }
-
- static const VMStateDescription vmstate_virtio_balloon = {
-diff --git a/include/hw/virtio/virtio-balloon.h b/include/hw/virtio/virtio-balloon.h
-index 1afafb12f6..f212c08bd7 100644
---- a/include/hw/virtio/virtio-balloon.h
-+++ b/include/hw/virtio/virtio-balloon.h
-@@ -45,6 +45,7 @@ enum virtio_balloon_free_page_report_status {
- typedef struct VirtIOBalloon {
- VirtIODevice parent_obj;
- VirtQueue *ivq, *dvq, *svq, *free_page_vq;
-+ bool use_large_config;
- uint32_t free_page_report_status;
- uint32_t num_pages;
- uint32_t actual;
projects / pve-qemu.git / commitdiff