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    SubjectRe: [PATCH v2 14/28] KVM: VMX: Check VM_ENTRY_IA32E_MODE in setup_vmcs_config()
    On Wed, Jun 29, 2022 at 8:07 AM Vitaly Kuznetsov <vkuznets@redhat.com> wrote:
    >
    > VM_ENTRY_IA32E_MODE control is toggled dynamically by vmx_set_efer()
    > and setup_vmcs_config() doesn't check its existence. On the contrary,
    > nested_vmx_setup_ctls_msrs() doesn set it on x86_64. Add the missing
    > check and filter the bit out in vmx_vmentry_ctrl().
    >
    > No (real) functional change intended as all existing CPUs supporting
    > long mode and VMX are supposed to have it.
    >
    > Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
    > ---
    > arch/x86/kvm/vmx/vmx.c | 15 ++++++++++++---
    > 1 file changed, 12 insertions(+), 3 deletions(-)
    >
    > diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
    > index 83feb70d44a9..da8bbba38d0e 100644
    > --- a/arch/x86/kvm/vmx/vmx.c
    > +++ b/arch/x86/kvm/vmx/vmx.c
    > @@ -2610,6 +2610,9 @@ static __init int setup_vmcs_config(struct vmcs_config *vmcs_conf,
    > _pin_based_exec_control &= ~PIN_BASED_POSTED_INTR;
    >
    > min = VM_ENTRY_LOAD_DEBUG_CONTROLS;
    > +#ifdef CONFIG_X86_64
    > + min |= VM_ENTRY_IA32E_MODE;
    > +#endif
    > opt = VM_ENTRY_LOAD_IA32_PERF_GLOBAL_CTRL |
    > VM_ENTRY_LOAD_IA32_PAT |
    > VM_ENTRY_LOAD_IA32_EFER |
    > @@ -4242,9 +4245,15 @@ static u32 vmx_vmentry_ctrl(void)
    > if (vmx_pt_mode_is_system())
    > vmentry_ctrl &= ~(VM_ENTRY_PT_CONCEAL_PIP |
    > VM_ENTRY_LOAD_IA32_RTIT_CTL);
    > - /* Loading of EFER and PERF_GLOBAL_CTRL are toggled dynamically */
    > - return vmentry_ctrl &
    > - ~(VM_ENTRY_LOAD_IA32_PERF_GLOBAL_CTRL | VM_ENTRY_LOAD_IA32_EFER);
    > + /*
    > + * Loading of EFER, VM_ENTRY_IA32E_MODE, and PERF_GLOBAL_CTRL
    > + * are toggled dynamically.
    > + */
    Nit: Previously, this could be read as "loading of (EFER and
    PERF_GLOBAL_CTRL)." Since "loading" doesn't apply to IA32e mode,
    you've lost "loading" of PERF_GLOBAL_CONTROL. Also, why drop the
    VM_ENTRY prefix from the MSRs and not from IA32e mode?
    Perhaps:

    /*
    * IA32e mode, and loading of EFER and PERF_GLOBAL_CTRL are toggled dynamically.
    */

    > + vmentry_ctrl &= ~(VM_ENTRY_LOAD_IA32_PERF_GLOBAL_CTRL |
    > + VM_ENTRY_LOAD_IA32_EFER |
    > + VM_ENTRY_IA32E_MODE);
    > +
    > + return vmentry_ctrl;
    > }
    >
    > static u32 vmx_vmexit_ctrl(void)
    > --
    > 2.35.3
    >
    Reviewed-by: Jim Mattson <jmattson@google.com>

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