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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: 09abe32002 ("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>
This commit is contained in:
Sean Christopherson 2019-05-07 09:06:30 -07:00 committed by Paolo Bonzini
parent c538d57f67
commit 4d6c989284
1 changed files with 10 additions and 11 deletions
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21
arch/x86/kvm/vmx/nested.c
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@ -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
*/