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c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1772809404; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=eldssNcwL2vzqR/skuruxhEOMx/slaPtYj/2cYe4PG0=; b=JE4mOVYsZFrNuMq0geAzbZtNhrWDoXXYYx7CmWJ5B7HUt2e2VV0VlubDFefwyOTNX08xIx x8jFB8JXAwtYGReIbxVQRysUoY8m9PriC0fYiyxvn3yCx587A7nLb+mWYOi5r6yqf7ISyi rtMvAxNCr8B436hTjDJwaqcnOKhShRc= X-MC-Unique: gspfo7W7O96rgc5S92frEw-1 X-Mimecast-MFC-AGG-ID: gspfo7W7O96rgc5S92frEw_1772809400 From: Eric Auger To: eric.auger.pro@gmail.com, eric.auger@redhat.com, qemu-devel@nongnu.org, qemu-arm@nongnu.org, peter.maydell@linaro.org, cohuck@redhat.com, sebott@redhat.com, peterx@redhat.com, philmd@linaro.org, alex.bennee@linaro.org Subject: [PATCH v9 3/6] target/arm/cpu64: Mitigate migration failures due to spurious TCR_EL1, PIRE0_EL1 and PIR_EL1 Date: Fri, 6 Mar 2026 16:02:21 +0100 Message-ID: <20260306150302.203112-4-eric.auger@redhat.com> In-Reply-To: <20260306150302.203112-1-eric.auger@redhat.com> References: <20260306150302.203112-1-eric.auger@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=170.10.129.124; envelope-from=eric.auger@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -9 X-Spam_score: -1.0 X-Spam_bar: - X-Spam_report: (-1.0 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.411, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.679, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: qemu development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZohoMail-DKIM: pass (identity @redhat.com) X-ZM-MESSAGEID: 1772809659543158500 Before linux v6.13 those registers were erroneously unconditionally exposed and this was fixed by commits: - 0fcb4eea5345 ("KVM: arm64: Hide TCR2_EL1 from userspace when disabled for guests") - a68cddbe47ef=C2=A0("KVM: arm64: Hide S1PIE registers from userspace when disabled for guests") in v6.13. This means if we migrate from an old kernel host to a >=3D 6.13 kernel host, migration currently fails. Declare cpreg migration tolerance for those registers. Signed-off-by: Eric Auger Reviewed-by: Sebastian Ott --- target/arm/cpu64.c | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) diff --git a/target/arm/cpu64.c b/target/arm/cpu64.c index d6feba220e8..4cfddc6e8c0 100644 --- a/target/arm/cpu64.c +++ b/target/arm/cpu64.c @@ -810,6 +810,31 @@ static void aarch64_a53_initfn(Object *obj) define_cortex_a72_a57_a53_cp_reginfo(cpu); } =20 +static void kvm_arm_set_cpreg_mig_tolerances(ARMCPU *cpu) +{ + /* + * Registers that may be in the incoming stream and not exposed + * on the destination + */ + + /* + * TCR_EL1 was erroneously unconditionnally exposed before linux v6.13. + * See commit 0fcb4eea5345 ("KVM: arm64: Hide TCR2_EL1 from userspace + * when disabled for guests") + */ + arm_register_cpreg_mig_tolerance(cpu, ARM64_SYS_REG(3, 0, 2, 0, 3), + 0, 0, ToleranceNotOnBothEnds); + /* + * PIRE0_EL1 and PIR_EL1 were erroneously unconditionnally exposed + * before linux v6.13. See commit a68cddbe47ef=C2=A0("KVM: arm64: Hide + * S1PIE registers from userspace when disabled for guests") + */ + arm_register_cpreg_mig_tolerance(cpu, ARM64_SYS_REG(3, 0, 10, 2, 2), + 0, 0, ToleranceNotOnBothEnds); + arm_register_cpreg_mig_tolerance(cpu, ARM64_SYS_REG(3, 0, 10, 2, 3), + 0, 0, ToleranceNotOnBothEnds); +} + static void aarch64_host_initfn(Object *obj) { ARMCPU *cpu =3D ARM_CPU(obj); @@ -822,6 +847,7 @@ static void aarch64_host_initfn(Object *obj) #endif =20 #if defined(CONFIG_KVM) + kvm_arm_set_cpreg_mig_tolerances(cpu); kvm_arm_set_cpu_features_from_host(cpu); aarch64_add_sve_properties(obj); #elif defined(CONFIG_HVF) --=20 2.53.0