pve-qemu-qoup/debian/patches/pve/0024-PVE-Compat-4.0-used-balloon-qemu-4-0-config-size-fal.patch
Fiona Ebner f06b222ece fixes for QEMU 9.0
Most importantly, fix forwards and backwards migration with VirtIO-GPU
display.

Other fixes are for a regression in pflash device (introduced in 8.2)
and some fixes for x86(_64) TCG emulation. One of the patches needed
to be adapted, because it removed a helper that is still in use in
9.0.0.

There also is a revert for a fix in VirtIO PCI devices that turned out
to cause some issues, see the revert itself for more details.

Lastly, there is a change to move compatibility flags for a new
VirtIO-net feature to the correct machine type. The feature was
introduced in QEMU 8.2, but the compatibility flags got added to
machine version 8.0 instead of 8.1. This breaks backwards migration
with machine version 8.1 from a 8.2/9.0 binary to an 8.1 binary, in
cases where the guest kernel enables the feature (e.g. Ubuntu 23.10).
While that breaks migration with machine version 8.1 from an unpatched
to a patched binary, Proxmox VE only ever had 8.2 on the test
repository and 9.0 not yet in any public repository. An upstream
developer suggested it is the proper fix [0]. Upstream submission [1].

[0]: https://lore.kernel.org/qemu-devel/CACGkMEtZrJuhof+hUGVRvLLQE+8nQE5XmSHpT0NAQ1EpnqfmsA@mail.gmail.com/T/#u
[1]: https://lore.kernel.org/qemu-devel/20240517075336.104091-1-f.ebner@proxmox.com/T/#u

Signed-off-by: Fiona Ebner <f.ebner@proxmox.com>
2024-05-17 15:56:12 +02:00

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1.8 KiB
Diff

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Thomas Lamprecht <t.lamprecht@proxmox.com>
Date: Mon, 6 Apr 2020 12:16:54 +0200
Subject: [PATCH] PVE: [Compat]: 4.0 used balloon qemu-4-0-config-size false
here
The underlying issue why this change from upstream to us arised in
the first place is that QEMU 4.0 was already released at the point we
run into this migration issue, so we did the then obvious fallback to
false for virtio-balloon-device qemu-4-0-config-size.
QEMU made that switch back in 4.1, where it now uses a backward
compatible mechanism to detect if the bigger CFG sizes should be
used, i.e., checking the VIRTIO_BALLOON_F_PAGE_POISON or
VIRTIO_BALLOON_F_FREE_PAGE_HINT balloon feature flags.
As for them, upstream released version 4.0 had this to true they keep
it to true in their compatibility record for the 4.0 machine, to
allow live migrations from 4.0 to 4.1.
As for us, downstream released version 4.0 (first public release of
this QEMU) had this to false, we change it back to false again, for
the same reason.
Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
---
hw/core/machine.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/hw/core/machine.c b/hw/core/machine.c
index 4273de16a0..83f1fc0293 100644
--- a/hw/core/machine.c
+++ b/hw/core/machine.c
@@ -162,7 +162,8 @@ GlobalProperty hw_compat_4_0[] = {
{ "virtio-vga", "edid", "false" },
{ "virtio-gpu-device", "edid", "false" },
{ "virtio-device", "use-started", "false" },
- { "virtio-balloon-device", "qemu-4-0-config-size", "true" },
+ // PVE differed from upstream for 4.0 balloon cfg size
+ { "virtio-balloon-device", "qemu-4-0-config-size", "false" },
{ "pl031", "migrate-tick-offset", "false" },
};
const size_t hw_compat_4_0_len = G_N_ELEMENTS(hw_compat_4_0);