Some additional comments to preexisting code: Explain who (L0 or L1) handles EPT violation and misconfiguration exits. Don't mention "shadow on either EPT or shadow" as the only two options. Signed-off-by: Nadav Har'El <nyh@xxxxxxxxxx> --- arch/x86/kvm/vmx.c | 21 +++++++++++++++++++-- 1 file changed, 19 insertions(+), 2 deletions(-) --- .before/arch/x86/kvm/vmx.c 2012-08-01 17:22:47.000000000 +0300 +++ .after/arch/x86/kvm/vmx.c 2012-08-01 17:22:47.000000000 +0300 @@ -5952,7 +5952,20 @@ static bool nested_vmx_exit_handled(stru return nested_cpu_has2(vmcs12, SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES); case EXIT_REASON_EPT_VIOLATION: + /* + * L0 always deals with the EPT violation. If nested EPT is + * used, and the nested mmu code discovers that the address is + * missing in the guest EPT table (EPT12), the EPT violation + * will be injected with nested_ept_inject_page_fault() + */ + return 0; case EXIT_REASON_EPT_MISCONFIG: + /* + * L2 never uses directly L1's EPT, but rather L0's own EPT + * table (shadow on EPT) or a merged EPT table that L0 built + * (EPT on EPT). So any problems with the structure of the + * table is L0's fault. + */ return 0; case EXIT_REASON_WBINVD: return nested_cpu_has2(vmcs12, SECONDARY_EXEC_WBINVD_EXITING); @@ -6881,7 +6894,12 @@ static void prepare_vmcs02(struct kvm_vc vmx_set_cr4(vcpu, vmcs12->guest_cr4); vmcs_writel(CR4_READ_SHADOW, nested_read_cr4(vmcs12)); - /* shadow page tables on either EPT or shadow page tables */ + /* + * Note that kvm_set_cr3() and kvm_mmu_reset_context() will do the + * right thing, and set GUEST_CR3 and/or EPT_POINTER in all supported + * settings: 1. shadow page tables on shadow page tables, 2. shadow + * page tables on EPT, 3. EPT on EPT. + */ kvm_set_cr3(vcpu, vmcs12->guest_cr3); kvm_mmu_reset_context(vcpu); @@ -7220,7 +7238,6 @@ void load_vmcs12_host_state(struct kvm_v if (nested_cpu_has_ept(vmcs12)) nested_ept_uninit_mmu_context(vcpu); - /* shadow page tables on either EPT or shadow page tables */ kvm_set_cr3(vcpu, vmcs12->host_cr3); kvm_mmu_reset_context(vcpu); -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
