On 07/15/2014 08:09 PM, Gleb Natapov wrote:
On Tue, Jul 15, 2014 at 01:52:40PM +0200, Jan Kiszka wrote:
......

I cannot follow your concerns yet. Specifically, how should
APIC_ACCESS_ADDR (the VMCS field, right?) change while L2 is running? We
currently pin/unpin on L1->L2/L2->L1, respectively. Or what do you mean?

I am talking about this case:
          if (cpu_has_secondary_exec_ctrls()) {a
          } else {
              exec_control |=
                 SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES;
             vmcs_write64(APIC_ACCESS_ADDR,
                 page_to_phys(vcpu->kvm->arch.apic_access_page));
          }
We do not pin here.


Hi Gleb,


7905 if (exec_control & SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES) {
......
7912 if (vmx->nested.apic_access_page) /* shouldn't happen */ 7913 nested_release_page(vmx->nested.apic_access_page);
7914                         vmx->nested.apic_access_page =
7915 nested_get_page(vcpu, vmcs12->apic_access_addr);

I thought you were talking about the problem here. We pin vmcs12->apic_access_addr in memory. And I think we should do the same thing to this page as to L1 vm.
Right ?

......
7922                         if (!vmx->nested.apic_access_page)
7923                                 exec_control &=
7924 ~SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES;
7925                         else
7926                                 vmcs_write64(APIC_ACCESS_ADDR,
7927 page_to_phys(vmx->nested.apic_access_page)); 7928 } else if (vm_need_virtualize_apic_accesses(vmx->vcpu.kvm)) {
7929                         exec_control |=
7930 SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES;
7931                         vmcs_write64(APIC_ACCESS_ADDR,
7932 page_to_phys(vcpu->kvm->arch.apic_access_page));
7933                 }

And yes, we have the problem you said here. We can migrate the page while L2 vm is running.
So I think we should enforce L2 vm to exit to L1. Right ?

Thanks.


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