From: Fiona Ebner <f.ebner@proxmox.com>
To: pve-devel@lists.proxmox.com
Subject: Re: [pve-devel] [RFC kernel] revert problematic TSC multiplier commit
Date: Thu, 1 Sep 2022 08:25:50 +0200 [thread overview]
Message-ID: <26cef061-6d28-1d8b-b7a7-5810054ff023@proxmox.com> (raw)
In-Reply-To: <20220831132803.5596-1-f.ebner@proxmox.com>
Am 31.08.22 um 15:28 schrieb Fiona Ebner:
> which might be responsible for several issues reported in the
> community forum[0][1].
>
> In my case, loading a VM snapshot that originally was taken on
> a CPU from a different vendor often caused problems in other VMs(!).
> In particular, it often led to RCU stalls (with similar messages as in
> [1]) or slowdowns, and sometimes clock jumps far into the future (like
> in [0]). With this revert applied, everything seems to run smoothly
> even after loading the "bad" snapshot 10 times.
>
> [0] https://forum.proxmox.com/threads/112756/
> [1] https://forum.proxmox.com/threads/111494/
>
> Signed-off-by: Fiona Ebner <f.ebner@proxmox.com>
> ---
>
> Needed to build with an ABI bump, AFAICT because of the removed
> KVM_X86_OP(write_tsc_multiplier), but it's even an ABI break I guess?
> If this is not ok, we can either
> A) try to revert while keeping the ABI intact
> B) try to backport d1021a1bc47668aa715b7f2121086c9598bffcbf instead
Sorry, that's the hash in
git://git.launchpad.net/~ubuntu-kernel-test/ubuntu/+source/linux/+git/mainline-crack
Upstream it's 11d39e8cc43e1c6737af19ca9372e590061b5ad2
>
> That's the one reason it's RFC. The other is that I haven't had much
> time to look at the actual code yet.
>
> ...dd-vendor-callbacks-for-writing-the-.patch | 247 ++++++++++++++++++
> 1 file changed, 247 insertions(+)
> create mode 100644 patches/kernel/0032-Revert-KVM-X86-Add-vendor-callbacks-for-writing-the-.patch
>
> diff --git a/patches/kernel/0032-Revert-KVM-X86-Add-vendor-callbacks-for-writing-the-.patch b/patches/kernel/0032-Revert-KVM-X86-Add-vendor-callbacks-for-writing-the-.patch
> new file mode 100644
> index 0000000..d2f7796
> --- /dev/null
> +++ b/patches/kernel/0032-Revert-KVM-X86-Add-vendor-callbacks-for-writing-the-.patch
> @@ -0,0 +1,247 @@
> +From 0747f18be1da2033a20c2a355678b9c278ce4603 Mon Sep 17 00:00:00 2001
> +From: Fiona Ebner <f.ebner@proxmox.com>
> +Date: Wed, 31 Aug 2022 13:49:55 +0200
> +Subject: [PATCH] Revert "KVM: X86: Add vendor callbacks for writing the TSC
> + multiplier"
> +
> +This reverts commit 1ab9287add5e265352d18517551abf6d01d004fd until commit
> +d1021a1bc47668aa715b7f2121086c9598bffcbf which fixes it can be cleanly
Same here
> +applied.
> +
> +Signed-off-by: Fiona Ebner <f.ebner@proxmox.com>
next prev parent reply other threads:[~2022-09-01 6:26 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-31 13:28 Fiona Ebner
2022-09-01 6:25 ` Fiona Ebner [this message]
[not found] ` <f7d1ae7c-5b8a-8cf7-8aff-979348b216ca@binovo.es>
2022-09-02 7:47 ` Fiona Ebner
[not found] ` <536bbaea-9f39-0b96-e16e-70c04c0852a5@binovo.es>
[not found] ` <1ca8041f-5099-ad72-9c86-ddc86c1aafff@binovo.es>
[not found] ` <c7e45768-c09a-1128-4f5a-5e9f3e0ec06d@binovo.es>
2022-09-14 7:50 ` Fiona Ebner
[not found] ` <4530687c-86ea-e9f6-c932-7f1f702d6647@binovo.es>
[not found] ` <be970183-0eae-9fc8-ad44-f8e90b78b62c@binovo.es>
2022-09-15 8:37 ` Fiona Ebner
[not found] ` <mailman.140.1663148345.354.pve-devel@lists.proxmox.com>
2022-09-15 10:44 ` Thomas Lamprecht
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