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From: jwarren@tutanota.com
To: Kvm <kvm@vger.kernel.org>
Subject: [Bug] AMD nested: commit broke VMware
Date: Mon, 29 May 2023 14:58:00 +0200 (CEST)	[thread overview]
Message-ID: <NWb_YOE--3-9@tutanota.com> (raw)

Hello,
Since kernel 5.16 users can't start VMware VMs when it is nested under KVM on AMD CPUs.

User reports are here:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2008583
https://forums.unraid.net/topic/128868-vmware-7x-will-not-start-any-vms-under-unraid-6110/

I've pinpointed it to commit 174a921b6975ef959dd82ee9e8844067a62e3ec1 (appeared in 5.16rc1)
"nSVM: Check for reserved encodings of TLB_CONTROL in nested VMCB"

I've confirmed that VMware errors out when it checks for TLB_CONTROL_FLUSH_ASID support and gets a 'false' answer.

First revisions of the patch in question had some support for TLB_CONTROL_FLUSH_ASID, but it was removed:
https://lore.kernel.org/kvm/f7c2d5f5-3560-8666-90be-3605220cb93c@redhat.com/

I don't know what would be the best case here, maybe put a quirk there, so it doesn't break "userspace".
Committer's email is dead, so I'm writing here.

             reply	other threads:[~2023-05-29 12:58 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-05-29 12:58 jwarren [this message]
2023-05-29 13:43 ` [Bug] AMD nested: commit broke VMware Maxim Levitsky
2023-05-30 20:10   ` Jim Mattson
2023-05-30 20:34     ` Jim Mattson
2023-05-31 10:35       ` Maxim Levitsky
2023-05-31 14:41         ` Sean Christopherson
2023-05-31 15:34           ` Jim Mattson
     [not found]           ` <CALMp9eTti7gSNKgR=h__SsoKynaR1tR2nHhuk_6tse-3FHJ7mw@mail.gmail.com-NWmRa0I----9>
2023-08-01  8:49             ` jwarren
2023-08-01 10:04               ` Maxim Levitsky

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