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authorSean Christopherson2023-06-13 13:30:36 -0700
committerGreg Kroah-Hartman2023-08-03 10:24:08 +0200
commitd8eb0c480f1e1ba0828b14edce17c4721c397440 (patch)
tree758f68a46a5781e021fa8a8b9d74648f6e3be56e /kernel/trace/power-traces.c
parented8bbe6627cf3cbe57e0b731cb8a7643496cdb99 (diff)
KVM: VMX: Don't fudge CR0 and CR4 for restricted L2 guest
commit c4abd7352023aa96114915a0bb2b88016a425cda upstream. Stuff CR0 and/or CR4 to be compliant with a restricted guest if and only if KVM itself is not configured to utilize unrestricted guests, i.e. don't stuff CR0/CR4 for a restricted L2 that is running as the guest of an unrestricted L1. Any attempt to VM-Enter a restricted guest with invalid CR0/CR4 values should fail, i.e. in a nested scenario, KVM (as L0) should never observe a restricted L2 with incompatible CR0/CR4, since nested VM-Enter from L1 should have failed. And if KVM does observe an active, restricted L2 with incompatible state, e.g. due to a KVM bug, fudging CR0/CR4 instead of letting VM-Enter fail does more harm than good, as KVM will often neglect to undo the side effects, e.g. won't clear rmode.vm86_active on nested VM-Exit, and thus the damage can easily spill over to L1. On the other hand, letting VM-Enter fail due to bad guest state is more likely to contain the damage to L2 as KVM relies on hardware to perform most guest state consistency checks, i.e. KVM needs to be able to reflect a failed nested VM-Enter into L1 irrespective of (un)restricted guest behavior. Cc: Jim Mattson <jmattson@google.com> Cc: stable@vger.kernel.org Fixes: bddd82d19e2e ("KVM: nVMX: KVM needs to unset "unrestricted guest" VM-execution control in vmcs02 if vmcs12 doesn't set it") Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20230613203037.1968489-3-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'kernel/trace/power-traces.c')
0 files changed, 0 insertions, 0 deletions