Messages in this thread | | | Subject | Re: [PATCH] KVM: nVMX: Handle split-lock #AC exceptions that happen in L2 | From | Paolo Bonzini <> | Date | Wed, 23 Jun 2021 14:30:37 +0200 |
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On 23/06/21 04:43, Xiaoyao Li wrote: >> >> + else if (is_alignment_check(intr_info) && >> + !vmx_guest_inject_ac(vcpu)) >> + return true; > > Why choose to check in nested_vmx_l0_wants_exit, not in > nested_vmx_l1_wants_exit()?
nested_vmx_l0_wants_exit() == true means "this is a vmexit that needs some transformation before being injected into L1". Instead, nested_vmx_l1_wants_exit() == true means "this is an event that should either be processed directly by L0, or cause a vmexit in L1"
Typically, nested_vmx_l1_wants_exit() checks the controls in vmcs12, while nested_vmx_l0_wants_exit() returns true unconditionally for most vmexits; for others it checks processor state, or other state set up by userspace with ioctls such as vcpu->guest_debug.
In this case it's *L0* that wants that vmexit, in order to either disable split-lock detection or inject a SIGBUS, so nested_vmx_l0_wants_exit() is the right one to test.
Paolo
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