From: Eric Auger <eric.auger@redhat.com>
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 ("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 >= 6.13 kernel
host, migration currently fails.
Declare cpreg migration tolerance for those registers.
Signed-off-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Sebastian Ott <sebott@redhat.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 20260420140552.104369-5-eric.auger@redhat.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
target/arm/cpu64.c | 28 ++++++++++++++++++++++++++++
1 file changed, 28 insertions(+)
diff --git a/target/arm/cpu64.c b/target/arm/cpu64.c
index d6feba220e..e7014022df 100644
--- a/target/arm/cpu64.c
+++ b/target/arm/cpu64.c
@@ -810,6 +810,33 @@ static void aarch64_a53_initfn(Object *obj)
define_cortex_a72_a57_a53_cp_reginfo(cpu);
}
+#if defined(CONFIG_KVM)
+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 ("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);
+}
+#endif
+
static void aarch64_host_initfn(Object *obj)
{
ARMCPU *cpu = ARM_CPU(obj);
@@ -822,6 +849,7 @@ static void aarch64_host_initfn(Object *obj)
#endif
#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)
--
2.43.0