linux-kernel - Re: [PATCH v4 2/3] KVM: nVMX: Validate the IA32

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Message-ID: <CALMp9eRJ_v0M0XuacCy4ZfwapygDDKN1+bYM4QudaOY6fJLJBQ@mail.gmail.com>
Date:   Fri, 3 Nov 2017 10:52:41 -0700
From:   Jim Mattson <jmattson@...gle.com>
To:     Wanpeng Li <kernellwp@...il.com>
Cc:     LKML <linux-kernel@...r.kernel.org>,
        kvm list <kvm@...r.kernel.org>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Radim Krčmář <rkrcmar@...hat.com>,
        Wanpeng Li <wanpeng.li@...mail.com>
Subject: Re: [PATCH v4 2/3] KVM: nVMX: Validate the IA32_BNDCFGS on nested VM-entry

On Thu, Nov 2, 2017 at 5:35 PM, Wanpeng Li <kernellwp@...il.com> wrote:
> From: Wanpeng Li <wanpeng.li@...mail.com>
>
> According to the SDM, if the "load IA32_BNDCFGS" VM-entry controls is 1, the
> following checks are performed on the field for the IA32_BNDCFGS MSR:
>  - Bits reserved in the IA32_BNDCFGS MSR must be 0.
>  - The linear address in bits 63:12 must be canonical.
>
> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
> Cc: Paolo Bonzini <pbonzini@...hat.com>
> Cc: Radim Krčmář <rkrcmar@...hat.com>
> Cc: Jim Mattson <jmattson@...gle.com>
> Signed-off-by: Wanpeng Li <wanpeng.li@...mail.com>
> ---
> v3 -> v4:
>  * simply condition
>  * use && instead of nested "if"s
>
>  arch/x86/kvm/vmx.c | 5 +++++
>  1 file changed, 5 insertions(+)
>
> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> index e6c8ffa..6cf3972 100644
> --- a/arch/x86/kvm/vmx.c
> +++ b/arch/x86/kvm/vmx.c
> @@ -10805,6 +10805,11 @@ static int check_vmentry_postreqs(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12,
>                         return 1;
>         }
>
> +       if (kvm_mpx_supported() &&

I think you kept the wrong conjunct from the previous version. Drop
kvm_mpx_supported() and restore the test for
(vmcs12->vm_entry_controls & VM_ENTRY_LOAD_BNDCFGS).

> +               (is_noncanonical_address(vmcs12->guest_bndcfgs & PAGE_MASK, vcpu) ||
> +               (vmcs12->guest_bndcfgs & MSR_IA32_BNDCFGS_RSVD)))
> +                       return 1;
> +
>         return 0;
>  }
>
> --
> 2.7.4
>