On Thu, Feb 18, 2021 at 8:35 AM Sean Christopherson <seanjc@xxxxxxxxxx> wrote: > > On Thu, Feb 18, 2021, Paolo Bonzini wrote: > > On 18/02/21 13:56, David Edmondson wrote: > > > On Thursday, 2021-02-18 at 12:54:52 +01, Paolo Bonzini wrote: > > > > > > > On 18/02/21 11:04, David Edmondson wrote: > > > > > When dumping the VMCS, retrieve the current guest value of EFER from > > > > > the kvm_vcpu structure if neither VM_EXIT_SAVE_IA32_EFER or > > > > > VM_ENTRY_LOAD_IA32_EFER is set, which can occur if the processor does > > > > > not support the relevant VM-exit/entry controls. > > > > > > > > Printing vcpu->arch.efer is not the best choice however. Could we dump > > > > the whole MSR load/store area instead? > > > > > > I'm happy to do that, and think that it would be useful, but it won't > > > help with the original problem (which I should have explained more). > > > > > > If the guest has EFER_LMA set but we aren't using the entry/exit > > > controls, vm_read64(GUEST_IA32_EFER) returns 0, causing dump_vmcs() to > > > erroneously dump the PDPTRs. > > > > Got it now. It would sort of help, because while dumping the MSR load/store > > area you could get hold of the real EFER, and use it to decide whether to > > dump the PDPTRs. > > EFER isn't guaranteed to be in the load list, either, e.g. if guest and host > have the same desired value. > > The proper way to retrieve the effective EFER is to reuse the logic in > nested_vmx_calc_efer(), i.e. look at VM_ENTRY_IA32E_MODE if EFER isn't being > loaded via VMCS. Shouldn't dump_vmcs() simply dump the contents of the VMCS, in its entirety? What does it matter what the value of EFER is?
