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    Subject[PATCH 5.10 268/452] KVM: nVMX: Leave most VM-Exit info fields unmodified on failed VM-Entry
    Date
    From: Sean Christopherson <seanjc@google.com>

    [ Upstream commit c3634d25fbee88e2368a8e0903ae0d0670eb9e71 ]

    Don't modify vmcs12 exit fields except EXIT_REASON and EXIT_QUALIFICATION
    when performing a nested VM-Exit due to failed VM-Entry. Per the SDM,
    only the two aformentioned fields are filled and "All other VM-exit
    information fields are unmodified".

    Fixes: 4704d0befb07 ("KVM: nVMX: Exiting from L2 to L1")
    Signed-off-by: Sean Christopherson <seanjc@google.com>
    Message-Id: <20220407002315.78092-3-seanjc@google.com>
    Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    arch/x86/kvm/vmx/nested.c | 15 ++++++++++-----
    1 file changed, 10 insertions(+), 5 deletions(-)

    diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
    index 0c2389d0fdaf..fe53cab1a8a6 100644
    --- a/arch/x86/kvm/vmx/nested.c
    +++ b/arch/x86/kvm/vmx/nested.c
    @@ -4143,12 +4143,12 @@ static void prepare_vmcs12(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12,
    /* update exit information fields: */
    vmcs12->vm_exit_reason = vm_exit_reason;
    vmcs12->exit_qualification = exit_qualification;
    - vmcs12->vm_exit_intr_info = exit_intr_info;
    -
    - vmcs12->idt_vectoring_info_field = 0;
    - vmcs12->vm_exit_instruction_len = vmcs_read32(VM_EXIT_INSTRUCTION_LEN);
    - vmcs12->vmx_instruction_info = vmcs_read32(VMX_INSTRUCTION_INFO);

    + /*
    + * On VM-Exit due to a failed VM-Entry, the VMCS isn't marked launched
    + * and only EXIT_REASON and EXIT_QUALIFICATION are updated, all other
    + * exit info fields are unmodified.
    + */
    if (!(vmcs12->vm_exit_reason & VMX_EXIT_REASONS_FAILED_VMENTRY)) {
    vmcs12->launch_state = 1;

    @@ -4160,8 +4160,13 @@ static void prepare_vmcs12(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12,
    * Transfer the event that L0 or L1 may wanted to inject into
    * L2 to IDT_VECTORING_INFO_FIELD.
    */
    + vmcs12->idt_vectoring_info_field = 0;
    vmcs12_save_pending_event(vcpu, vmcs12);

    + vmcs12->vm_exit_intr_info = exit_intr_info;
    + vmcs12->vm_exit_instruction_len = vmcs_read32(VM_EXIT_INSTRUCTION_LEN);
    + vmcs12->vmx_instruction_info = vmcs_read32(VMX_INSTRUCTION_INFO);
    +
    /*
    * According to spec, there's no need to store the guest's
    * MSRs if the exit is due to a VM-entry failure that occurs
    --
    2.35.1


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