KVM: nVMX: Don't rewrite GUEST_PML_INDEX during nested VM-Entry

Emulation of GUEST_PML_INDEX for a nested VMM is a bit weird.  Because
L0 flushes the PML on every VM-Exit, the value in vmcs02 at the time of
VM-Enter is a constant -1, regardless of what L1 thinks/wants.

Fixes: 09abe32002665 ("KVM: nVMX: split pieces of prepare_vmcs02() to prepare_vmcs02_early()")
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 7b6628edd617f48d95b9da7da1fbdbc11f5b6cc5..a090bfb10796e5959c6bc6809418e3e35b392fe5 100644 (file)
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -1940,8 +1940,17 @@ static void prepare_vmcs02_constant_state(struct vcpu_vmx *vmx)
        if (cpu_has_vmx_msr_bitmap())
                vmcs_write64(MSR_BITMAP, __pa(vmx->nested.vmcs02.msr_bitmap));
 
-       if (enable_pml)
+       /*
+        * The PML address never changes, so it is constant in vmcs02.
+        * Conceptually we want to copy the PML index from vmcs01 here,
+        * and then back to vmcs01 on nested vmexit.  But since we flush
+        * the log and reset GUEST_PML_INDEX on each vmexit, the PML
+        * index is also effectively constant in vmcs02.
+        */
+       if (enable_pml) {
                vmcs_write64(PML_ADDRESS, page_to_phys(vmx->pml_pg));
+               vmcs_write16(GUEST_PML_INDEX, PML_ENTITY_NUM - 1);
+       }
 
        if (cpu_has_vmx_encls_vmexit())
                vmcs_write64(ENCLS_EXITING_BITMAP, -1ull);
@@ -2101,16 +2110,6 @@ static void prepare_vmcs02_early(struct vcpu_vmx *vmx, struct vmcs12 *vmcs12)
                exec_control |= VM_EXIT_LOAD_IA32_EFER;
        vm_exit_controls_init(vmx, exec_control);
 
-       /*
-        * Conceptually we want to copy the PML address and index from
-        * vmcs01 here, and then back to vmcs01 on nested vmexit. But,
-        * since we always flush the log on each vmexit and never change
-        * the PML address (once set), this happens to be equivalent to
-        * simply resetting the index in vmcs02.
-        */
-       if (enable_pml)
-               vmcs_write16(GUEST_PML_INDEX, PML_ENTITY_NUM - 1);
-
        /*
         * Interrupt/Exception Fields
         */