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Peter Anvin" Subject: [PATCH v12 11/24] KVM: x86: Add fault checks for guest CR4.CET setting Date: Mon, 11 Aug 2025 19:55:19 -0700 Message-ID: <20250812025606.74625-12-chao.gao@intel.com> X-Mailer: git-send-email 2.47.1 In-Reply-To: <20250812025606.74625-1-chao.gao@intel.com> References: <20250812025606.74625-1-chao.gao@intel.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Yang Weijiang Check potential faults for CR4.CET setting per Intel SDM requirements. CET can be enabled if and only if CR0.WP =3D=3D 1, i.e. setting CR4.CET =3D= =3D 1 faults if CR0.WP =3D=3D 0 and setting CR0.WP =3D=3D 0 fails if CR4.CET = =3D=3D 1. Co-developed-by: Sean Christopherson Signed-off-by: Sean Christopherson Signed-off-by: Yang Weijiang Reviewed-by: Chao Gao Reviewed-by: Maxim Levitsky Tested-by: Mathias Krause Tested-by: John Allen Signed-off-by: Chao Gao --- 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 f87974e0682b..cca05908f989 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -1172,6 +1172,9 @@ 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; =20 + if (!(cr0 & X86_CR0_WP) && kvm_is_cr4_bit_set(vcpu, X86_CR4_CET)) + return 1; + kvm_x86_call(set_cr0)(vcpu, cr0); =20 kvm_post_set_cr0(vcpu, old_cr0, cr0); @@ -1371,6 +1374,9 @@ int kvm_set_cr4(struct kvm_vcpu *vcpu, unsigned long = cr4) return 1; } =20 + if ((cr4 & X86_CR4_CET) && !kvm_is_cr0_bit_set(vcpu, X86_CR0_WP)) + return 1; + kvm_x86_call(set_cr4)(vcpu, cr4); =20 kvm_post_set_cr4(vcpu, old_cr4, cr4); --=20 2.47.1