On 2013-09-03 10:39, Gleb Natapov wrote:
> On Thu, Aug 08, 2013 at 04:26:32PM +0200, Jan Kiszka wrote:
>> This job is normally performed by the architectural EFER set service
>> which we cannot use as it prevents transitions that are valid when
>> switching between L1 and L2. So open-code the update of base_role.nxe
>> after changing EFER on VM-entry and exit.
>>
>> Signed-off-by: Jan Kiszka <jan.kiszka@xxxxxxxxxxx>
>> ---
>> arch/x86/kvm/vmx.c | 4 ++++
>> 1 files changed, 4 insertions(+), 0 deletions(-)
>>
>> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
>> index 9b0510b..7cc208a 100644
>> --- a/arch/x86/kvm/vmx.c
>> +++ b/arch/x86/kvm/vmx.c
>> @@ -7735,6 +7735,8 @@ static void prepare_vmcs02(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12)
>> vcpu->arch.efer &= ~(EFER_LMA | EFER_LME);
>> /* Note: modifies VM_ENTRY/EXIT_CONTROLS and GUEST/HOST_IA32_EFER */
>> vmx_set_efer(vcpu, vcpu->arch.efer);
>> + vcpu->arch.mmu.base_role.nxe =
>> + (vcpu->arch.efer & EFER_NX) && !enable_ept;
>>
> kvm_mmu_reset_context() called later in this function does that.
For all relevant scenarios? The code is pretty convoluted, so this is
non-obvious for me: kvm_mmu_reset_context calls init_kvm_mmu which may
call init_kvm_softmmu that does kvm_init_shadow_mmu with nxe
initialization. But is that path always taken?
Jan
>
>> if (nested_cpu_has_ept(vmcs12)) {
>> kvm_mmu_unload(vcpu);
>> @@ -8179,6 +8181,8 @@ static void load_vmcs12_host_state(struct kvm_vcpu *vcpu,
>> else
>> vcpu->arch.efer &= ~(EFER_LMA | EFER_LME);
>> vmx_set_efer(vcpu, vcpu->arch.efer);
>> + vcpu->arch.mmu.base_role.nxe =
>> + (vcpu->arch.efer & EFER_NX) && !enable_ept;
>>
> Same here.
>
>> kvm_register_write(vcpu, VCPU_REGS_RSP, vmcs12->host_rsp);
>> kvm_register_write(vcpu, VCPU_REGS_RIP, vmcs12->host_rip);
>> --
>> 1.7.3.4
>
> --
> Gleb.
>
--
Siemens AG, Corporate Technology, CT RTC ITP SES-DE
Corporate Competence Center Embedded Linux
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