Am 19.03.25 um 17:39 schrieb Fiona Ebner:
> As reported in the community forum [0][1], QEMU processes for Linux
> guests would consume more CPU on the host after an update to QEMU 9.2.
> The issue was reproduced and bisecting pointed to QEMU commit
> f0ccf77078 ("hpet: fix and cleanup persistence of interrupt status").
>
> Some quick experimentation suggests that in particular the last part
> is responsible for the issue:
>> - the timer must be kept running even if not enabled, in
>> order to set the ISR flag, so writes to HPET_TN_CFG must
>> not call hpet_del_timer()
>
> Users confirmed that setting the hpet=off machine flag works around
> the issue[0]. For Windows (7 or later) guests, the flag is already
> disabled, because of issues in the past [2].
>
> Upstream suggested reverting the relevant patches for now [3], because
> other issues were reported too. All except commit 5895879aca ("hpet:
> remove unnecessary variable "index"") are actually dependent on each
> other for cleanly reverting f0ccf77078, and while not strictly
> required, that one was reverted too for completeness.
>
> [0]: https://forum.proxmox.com/threads/163694/
> [1]: https://forum.proxmox.com/threads/161849/post-756793
> [2]: https://lists.proxmox.com/pipermail/pve-devel/2012-December/004958.html
> [3]:
> https://lore.kernel.org/qemu-devel/cabgobfakj5nfvkmylfmu4c0izzljjtcwkslczya0tboz0ko...@mail.gmail.com/
>
> Signed-off-by: Fiona Ebner <f.eb...@proxmox.com>
> ---
> ...void-timer-storms-on-periodic-timers.patch | 50 ++++
> ...e-full-64-bit-target-value-of-the-co.patch | 203 +++++++++++++
> ...-hpet-accept-64-bit-reads-and-writes.patch | 281 ++++++++++++++++++
> ...e-read-only-bits-directly-in-new_val.patch | 64 ++++
> ...et-remove-unnecessary-variable-index.patch | 68 +++++
> ...re-high-bits-of-comparator-in-32-bit.patch | 40 +++
> ...and-cleanup-persistence-of-interrupt.patch | 120 ++++++++
> debian/patches/series | 7 +
> 8 files changed, 833 insertions(+)
> create mode 100644
> debian/patches/pve/0051-Revert-hpet-avoid-timer-storms-on-periodic-timers.patch
> create mode 100644
> debian/patches/pve/0052-Revert-hpet-store-full-64-bit-target-value-of-the-co.patch
> create mode 100644
> debian/patches/pve/0053-Revert-hpet-accept-64-bit-reads-and-writes.patch
> create mode 100644
> debian/patches/pve/0054-Revert-hpet-place-read-only-bits-directly-in-new_val.patch
> create mode 100644
> debian/patches/pve/0055-Revert-hpet-remove-unnecessary-variable-index.patch
> create mode 100644
> debian/patches/pve/0056-Revert-hpet-ignore-high-bits-of-comparator-in-32-bit.patch
> create mode 100644
> debian/patches/pve/0057-Revert-hpet-fix-and-cleanup-persistence-of-interrupt.patch
>
>
applied, thanks!
nit: would have moved the patches in another folder, potentially a new
dedicated hpet one, as this isn't a pve downstream adaption/extension,
but no biggie.
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