debian/patches/pve/0024-PVE-Compat-4.0-used-balloon-qemu-4-0-config-size-fal.patch

   1 From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
   2 From: Thomas Lamprecht <t.lamprecht@proxmox.com>
   3 Date: Mon, 6 Apr 2020 12:16:54 +0200
   4 Subject: [PATCH] PVE: [Compat]: 4.0 used balloon qemu-4-0-config-size false
   5  here
   6
   7 The underlying issue why this change from upstream to us arised in
   8 the first place is that QEMU 4.0 was already released at the point we
   9 run into this migration issue, so we did the then obvious fallback to
  10 false for virtio-balloon-device qemu-4-0-config-size.
  11
  12 QEMU made that switch back in 4.1, where it now uses a backward
  13 compatible mechanism to detect if the bigger CFG sizes should be
  14 used, i.e., checking the VIRTIO_BALLOON_F_PAGE_POISON or
  15 VIRTIO_BALLOON_F_FREE_PAGE_HINT balloon feature flags.
  16 As for them, upstream released version 4.0 had this to true they keep
  17 it to true in their compatibility record for the 4.0 machine, to
  18 allow live migrations from 4.0 to 4.1.
  19 As for us, downstream released version 4.0 (first public release of
  20 this QEMU) had this to false, we change it back to false again, for
  21 the same reason.
  22
  23 Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
  24 ---
  25  hw/core/machine.c | 3 ++-
  26  1 file changed, 2 insertions(+), 1 deletion(-)
  27
  28 diff --git a/hw/core/machine.c b/hw/core/machine.c
  29 index a673302cce..fa424440bd 100644
  30 --- a/hw/core/machine.c
  31 +++ b/hw/core/machine.c
  32 @@ -127,7 +127,8 @@ GlobalProperty hw_compat_4_0[] = {
  33      { "virtio-vga",     "edid", "false" },
  34      { "virtio-gpu-device", "edid", "false" },
  35      { "virtio-device", "use-started", "false" },
  36 -    { "virtio-balloon-device", "qemu-4-0-config-size", "true" },
  37 +    // PVE differed from upstream for 4.0 balloon cfg size
  38 +    { "virtio-balloon-device", "qemu-4-0-config-size", "false" },
  39      { "pl031", "migrate-tick-offset", "false" },
  40  };
  41  const size_t hw_compat_4_0_len = G_N_ELEMENTS(hw_compat_4_0);