Merge ~paelzer/ubuntu/+source/qemu:fix-1848497-virt-balloon-migrate-eoan into ubuntu/+source/qemu:ubuntu/eoan-devel

[Christian Ehrhardt ]

[Christian Ehrhardt  (paelzer)]

PPA: https://launchpad.net/~paelzer/+archive/ubuntu/bug-1848497-virt-balloon-migrate/+packages

I have multiple changes for qemu inbound, and we know Focal is coming but not yet open.
I have made PPAs and MPs for Eoan and will submit them separate.

Lets review and ack it on that base, I'll eventually upload it to Focal first (with normal new version) and then kick off an SRU.

[Christian Ehrhardt  (paelzer)]

Focal is properly open and we know nothing else will be stacked for this upload.
Abandonign this one ...
New MP for both at once: https://code.launchpad.net/~paelzer/ubuntu/+source/qemu/+git/qemu/+merge/374447

review: Needs Resubmitting

Unmerged commits

e3a095c... by Christian Ehrhardt  on 2019-10-21

changelog MERGE

Signed-off-by: Christian Ehrhardt <email address hidden>

cd3c742... by Christian Ehrhardt  on 2019-10-21

changelog: fix migration issue from qemu <4.0 when using virtio-balloon (LP: #1848497)

Signed-off-by: Christian Ehrhardt <email address hidden>

96453b8... by Christian Ehrhardt  on 2019-10-21

fix migration issue from qemu <4.0 when using virtio-balloon (LP: #1848497)

Signed-off-by: Christian Ehrhardt <email address hidden>

diff --git a/debian/changelog b/debian/changelog
index 430c149..4177f2a 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,3 +1,10 @@
+qemu (1:4.0+dfsg-0ubuntu9.1) eoan; urgency=medium
+
+  * d/p/u/lp-1848497-virtio-balloon-fix-QEMU-4.0-config-size-migration-in.patch:
+    fix migration issue from qemu <4.0 when using virtio-balloon (LP: #1848497)
+
+ -- Christian Ehrhardt <[e-mail]>  Mon, 21 Oct 2019 15:58:57 +0200
+
 qemu (1:4.0+dfsg-0ubuntu9) eoan; urgency=medium
 
   * d/p/lp-1842774-s390x-cpumodel-Add-the-z15-name-to-the-description-o.patch:
diff --git a/debian/patches/series b/debian/patches/series
index 72b9e84..b3a43a4 100644
--- a/debian/patches/series
+++ b/debian/patches/series
@@ -31,3 +31,4 @@ ubuntu/lp-1836154-s390x-cpumodel-also-change-name-of-vxbeh.patch
 ubuntu/lp-1841066-i386-x86_cpu_list_feature_names-function.patch
 ubuntu/lp-1841066-i386-unavailable-features-QOM-property.patch
 lp-1842774-s390x-cpumodel-Add-the-z15-name-to-the-description-o.patch
+ubuntu/lp-1848497-virtio-balloon-fix-QEMU-4.0-config-size-migration-in.patch
diff --git a/debian/patches/ubuntu/lp-1848497-virtio-balloon-fix-QEMU-4.0-config-size-migration-in.patch b/debian/patches/ubuntu/lp-1848497-virtio-balloon-fix-QEMU-4.0-config-size-migration-in.patch
new file mode 100644
index 0000000..37e5f34
--- /dev/null
+++ b/debian/patches/ubuntu/lp-1848497-virtio-balloon-fix-QEMU-4.0-config-size-migration-in.patch
@@ -0,0 +1,137 @@
+From 2bbadb08ce272d65e1f78621002008b07d1e0f03 Mon Sep 17 00:00:00 2001
+From: Stefan Hajnoczi <[e-mail]>
+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 <[e-mail]>
+Signed-off-by: Stefan Hajnoczi <[e-mail]>
+Message-Id: <[e-mail]>
+Reviewed-by: Dr. David Alan Gilbert <[e-mail]>
+Tested-by: Dr. David Alan Gilbert <[e-mail]>
+Tested-by: Wolfgang Bumiller <[e-mail]>
+Reviewed-by: Michael S. Tsirkin <[e-mail]>
+Signed-off-by: Michael S. Tsirkin <[e-mail]>
+
+Backport-Note: upstream commit was targetted for 4.1, needed changes to
+work in 4.0 as HW_COMPAT code has the understanding of the "current"
+level and when backported that is 4.0 and not 4.1 anymore.
+Origin: backport, https://git.qemu.org/?p=qemu.git;a=commit;h=2bbadb08ce272d65e1f78621002008b07d1e0f03
+Bug-Ubuntu: https://bugs.launchpad.net/bugs/1848497
+Last-Update: 2019-10-21
+
+---
+ hw/core/machine.c                  |  2 ++
+ hw/virtio/virtio-balloon.c         | 28 +++++++++++++++++++++++++---
+ include/hw/virtio/virtio-balloon.h |  2 ++
+ 3 files changed, 29 insertions(+), 3 deletions(-)
+
+--- 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);
+ 
+--- a/hw/virtio/virtio-balloon.c
++++ b/hw/virtio/virtio-balloon.c
+@@ -615,6 +615,22 @@ virtio_balloon_free_page_report_notify(N
+     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(Vi
+     }
+ 
+     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(Vi
+     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 +782,7 @@ static void virtio_balloon_device_realiz
+     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);
+@@ -897,6 +913,18 @@ static Property virtio_balloon_propertie
+                     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.
++     * Backport:
++     * Original patch is for 4.1 and sets "false", but in HW_COMPAT sets
++     * 4.0 to "true" and 3.1 (and former) to "false".
++     * Emulate that in the 4.0 code by setting true here, and keeping the
++     * HW_COMPAT for 3.1 (4.0 HW_COMPAT doesn't exist yet anyway).
++     * That way it will be forward compatible to qemu >=4.1
++     */
++    DEFINE_PROP_BOOL("qemu-4-0-config-size", VirtIOBalloon,
++                     qemu_4_0_config_size, true),
+     DEFINE_PROP_LINK("iothread", VirtIOBalloon, iothread, TYPE_IOTHREAD,
+                      IOThread *),
+     DEFINE_PROP_END_OF_LIST(),
+--- 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