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    Subject[PATCH v8 16/26] KVM: x86: Add fault checks for guest CR4.CET setting
    Date
    Check potential faults for CR4.CET setting per Intel SDM requirements.
    CET can be enabled if and only if CR0.WP == 1, i.e. setting CR4.CET ==
    1 faults if CR0.WP == 0 and setting CR0.WP == 0 fails if CR4.CET == 1.

    Co-developed-by: Sean Christopherson <seanjc@google.com>
    Signed-off-by: Sean Christopherson <seanjc@google.com>
    Signed-off-by: Yang Weijiang <weijiang.yang@intel.com>
    Reviewed-by: Chao Gao <chao.gao@intel.com>
    Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
    ---
    arch/x86/kvm/x86.c | 6 ++++++
    1 file changed, 6 insertions(+)

    diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
    index bde780ae69bf..b418e4f5277b 100644
    --- a/arch/x86/kvm/x86.c
    +++ b/arch/x86/kvm/x86.c
    @@ -1006,6 +1006,9 @@ int kvm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)
    (is_64_bit_mode(vcpu) || kvm_is_cr4_bit_set(vcpu, X86_CR4_PCIDE)))
    return 1;

    + if (!(cr0 & X86_CR0_WP) && kvm_is_cr4_bit_set(vcpu, X86_CR4_CET))
    + return 1;
    +
    static_call(kvm_x86_set_cr0)(vcpu, cr0);

    kvm_post_set_cr0(vcpu, old_cr0, cr0);
    @@ -1217,6 +1220,9 @@ int kvm_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4)
    return 1;
    }

    + if ((cr4 & X86_CR4_CET) && !kvm_is_cr0_bit_set(vcpu, X86_CR0_WP))
    + return 1;
    +
    static_call(kvm_x86_set_cr4)(vcpu, cr4);

    kvm_post_set_cr4(vcpu, old_cr4, cr4);
    --
    2.39.3

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