Revert "nSVM: Check for reserved encodings of TLB_CONTROL in nested VMCB"
authorSean Christopherson <seanjc@google.com>
Wed, 18 Oct 2023 19:41:03 +0000 (12:41 -0700)
committerSean Christopherson <seanjc@google.com>
Thu, 30 Nov 2023 20:47:43 +0000 (12:47 -0800)
commita484755ab2526ebdbe042397cdd6e427eb4b1a68
tree36a55d39f2a54135a72e332c2d5dcb6faa7620b4
parente9e60c82fe391d04db55a91c733df4a017c28b2f
Revert "nSVM: Check for reserved encodings of TLB_CONTROL in nested VMCB"

Revert KVM's made-up consistency check on SVM's TLB control.  The APM says
that unsupported encodings are reserved, but the APM doesn't state that
VMRUN checks for a supported encoding.  Unless something is called out
in "Canonicalization and Consistency Checks" or listed as MBZ (Must Be
Zero), AMD behavior is typically to let software shoot itself in the foot.

This reverts commit 174a921b6975ef959dd82ee9e8844067a62e3ec1.

Fixes: 174a921b6975 ("nSVM: Check for reserved encodings of TLB_CONTROL in nested VMCB")
Reported-by: Stefan Sterz <s.sterz@proxmox.com>
Closes: https://lkml.kernel.org/r/b9915c9c-4cf6-051a-2d91-44cc6380f455%40proxmox.com
Cc: stable@vger.kernel.org
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Link: https://lore.kernel.org/r/20231018194104.1896415-2-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
arch/x86/kvm/svm/nested.c