On Thursday, 2021-02-18 at 14:01:40 +01, 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.
Okay, I'll do that and come back. Thanks!
> Thanks,
>
> Paolo
>
>
>>> Paolo
>>>
>>>> Fixes: 4eb64dce8d0a ("KVM: x86: dump VMCS on invalid entry")
>>>> Signed-off-by: David Edmondson <david.edmond...@oracle.com>
>>>> ---
>>>> arch/x86/kvm/vmx/vmx.c | 14 +++++++++-----
>>>> arch/x86/kvm/vmx/vmx.h | 2 +-
>>>> 2 files changed, 10 insertions(+), 6 deletions(-)
>>>>
>>>> diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
>>>> index eb69fef57485..74ea4fe6f35e 100644
>>>> --- a/arch/x86/kvm/vmx/vmx.c
>>>> +++ b/arch/x86/kvm/vmx/vmx.c
>>>> @@ -5754,7 +5754,7 @@ static void vmx_dump_dtsel(char *name, uint32_t
>>>> limit)
>>>> vmcs_readl(limit + GUEST_GDTR_BASE - GUEST_GDTR_LIMIT));
>>>> }
>>>>
>>>> -void dump_vmcs(void)
>>>> +void dump_vmcs(struct kvm_vcpu *vcpu)
>>>> {
>>>> u32 vmentry_ctl, vmexit_ctl;
>>>> u32 cpu_based_exec_ctrl, pin_based_exec_ctrl,
>>>> secondary_exec_control;
>>>> @@ -5771,7 +5771,11 @@ void dump_vmcs(void)
>>>> cpu_based_exec_ctrl = vmcs_read32(CPU_BASED_VM_EXEC_CONTROL);
>>>> pin_based_exec_ctrl = vmcs_read32(PIN_BASED_VM_EXEC_CONTROL);
>>>> cr4 = vmcs_readl(GUEST_CR4);
>>>> - efer = vmcs_read64(GUEST_IA32_EFER);
>>>> + if ((vmexit_ctl & VM_EXIT_SAVE_IA32_EFER) ||
>>>> + (vmentry_ctl & VM_ENTRY_LOAD_IA32_EFER))
>>>> + efer = vmcs_read64(GUEST_IA32_EFER);
>>>> + else
>>>> + efer = vcpu->arch.efer;
>>>> secondary_exec_control = 0;
>>>> if (cpu_has_secondary_exec_ctrls())
>>>> secondary_exec_control =
>>>> vmcs_read32(SECONDARY_VM_EXEC_CONTROL);
>>>> @@ -5955,7 +5959,7 @@ static int vmx_handle_exit(struct kvm_vcpu *vcpu,
>>>> fastpath_t exit_fastpath)
>>>> }
>>>>
>>>> if (exit_reason & VMX_EXIT_REASONS_FAILED_VMENTRY) {
>>>> - dump_vmcs();
>>>> + dump_vmcs(vcpu);
>>>> vcpu->run->exit_reason = KVM_EXIT_FAIL_ENTRY;
>>>> vcpu->run->fail_entry.hardware_entry_failure_reason
>>>> = exit_reason;
>>>> @@ -5964,7 +5968,7 @@ static int vmx_handle_exit(struct kvm_vcpu *vcpu,
>>>> fastpath_t exit_fastpath)
>>>> }
>>>>
>>>> if (unlikely(vmx->fail)) {
>>>> - dump_vmcs();
>>>> + dump_vmcs(vcpu);
>>>> vcpu->run->exit_reason = KVM_EXIT_FAIL_ENTRY;
>>>> vcpu->run->fail_entry.hardware_entry_failure_reason
>>>> = vmcs_read32(VM_INSTRUCTION_ERROR);
>>>> @@ -6049,7 +6053,7 @@ static int vmx_handle_exit(struct kvm_vcpu *vcpu,
>>>> fastpath_t exit_fastpath)
>>>>
>>>> unexpected_vmexit:
>>>> vcpu_unimpl(vcpu, "vmx: unexpected exit reason 0x%x\n",
>>>> exit_reason);
>>>> - dump_vmcs();
>>>> + dump_vmcs(vcpu);
>>>> vcpu->run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
>>>> vcpu->run->internal.suberror =
>>>> KVM_INTERNAL_ERROR_UNEXPECTED_EXIT_REASON;
>>>> diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h
>>>> index 9d3a557949ac..f8a0ce74798e 100644
>>>> --- a/arch/x86/kvm/vmx/vmx.h
>>>> +++ b/arch/x86/kvm/vmx/vmx.h
>>>> @@ -489,6 +489,6 @@ static inline bool vmx_guest_state_valid(struct
>>>> kvm_vcpu *vcpu)
>>>> return is_unrestricted_guest(vcpu) ||
>>>> __vmx_guest_state_valid(vcpu);
>>>> }
>>>>
>>>> -void dump_vmcs(void);
>>>> +void dump_vmcs(struct kvm_vcpu *vcpu);
>>>>
>>>> #endif /* __KVM_X86_VMX_H */
>>>>
>>
>> dme.
>>
dme.
--
But he said, leave me alone, I'm a family man.
