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c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1772447823; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=sKLoRoIQCgZ0YUK0eGLnjmDfdwRAbjP+XkZjC4Q6bw8=; b=RgGThNvG/BzmkDEdCmJBRWil4VfqgqNJEiAjcTFiGPIu6PwEZfHFLUzOQY2v+BXPgntmGh D6uD+ssMsYtPvDtvApQaIhk+8xzbcZFkV4ZE5kE0VTTEioy1rB9u7d/YDOdpK4NyqGg/ZT 2/JtNmdV177036uvPpx5s5pLDY9SkF4= X-MC-Unique: XlscyT2hMmOD5CDO-hlMBQ-1 X-Mimecast-MFC-AGG-ID: XlscyT2hMmOD5CDO-hlMBQ_1772447818 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 v7 3/7] target/arm/machine: Take account cpreg mig tolerances in case of mismatch Date: Mon, 2 Mar 2026 11:35:25 +0100 Message-ID: <20260302103640.1362564-4-eric.auger@redhat.com> In-Reply-To: <20260302103640.1362564-1-eric.auger@redhat.com> References: <20260302103640.1362564-1-eric.auger@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.93 Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; 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charset="utf-8" If there is a mismatch between the cpreg indexes found on both ends, check whether a tolerance was registered for the given kvmidx. If any, silence warning/errors. Create dedicated helper functions that print the name of the culprit reg and analyze whether a tolerance is set. According set the level of traces and analyze whether the migration must eventually fail. Signed-off-by: Eric Auger --- target/arm/machine.c | 67 +++++++++++++++++++++++++++-------------- target/arm/trace-events | 2 ++ 2 files changed, 47 insertions(+), 22 deletions(-) diff --git a/target/arm/machine.c b/target/arm/machine.c index 9297a8f5b41..abc66448cef 100644 --- a/target/arm/machine.c +++ b/target/arm/machine.c @@ -1046,6 +1046,45 @@ static gchar *print_register_name(uint64_t kvm_regid= x) } } =20 +/* + * Handle the situation where @kvmidx is on destination but not + * in the incoming stream. This never fails the migration. + */ +static void handle_cpreg_missing_in_incoming_stream(ARMCPU *cpu, uint64_t = kvmidx) +{ + g_autofree gchar *name =3D print_register_name(kvmidx); + + if (!arm_cpu_cpreg_has_mig_tolerance(cpu, kvmidx, + 0, 0, ToleranceNotOnBothEnds)) { + warn_report("%s: %s " + "expected by the destination but not in the incoming s= tream, " + "skip it", __func__, name); + } else { + trace_tolerate_cpreg_missing_in_incoming_stream(name); + } +} + +/* + * Handle the situation where @kvmidx is in the incoming + * stream but not on destination. This fails the migration if + * no cpreg mig tolerance is set for this @kvmidx + */ +static bool handle_cpreg_only_in_incoming_stream(ARMCPU *cpu, uint64_t kvm= idx) +{ + g_autofree gchar *name =3D print_register_name(kvmidx); + bool fail =3D false; + + if (!arm_cpu_cpreg_has_mig_tolerance(cpu, kvmidx, + 0, 0, ToleranceNotOnBothEnds)) { + error_report("%s: %s in the incoming stream but unknown on the " + "destination, fail migration", __func__, name); + fail =3D true; + } else { + trace_tolerate_cpreg_only_in_incoming_stream(name); + } + return fail; +} + static int cpu_post_load(void *opaque, int version_id) { ARMCPU *cpu =3D opaque; @@ -1085,21 +1124,12 @@ static int cpu_post_load(void *opaque, int version_= id) for (i =3D 0, v =3D 0; i < cpu->cpreg_array_len && v < cpu->cpreg_vmstate_array_len;) { if (cpu->cpreg_vmstate_indexes[v] > cpu->cpreg_indexes[i]) { - g_autofree gchar *name =3D print_register_name(cpu->cpreg_inde= xes[i]); - - warn_report("%s: %s " - "expected by the destination but not in the incomi= ng stream, " - "skip it", __func__, name); - i++; + handle_cpreg_missing_in_incoming_stream(cpu, cpu->cpreg_indexe= s[i++]); continue; } if (cpu->cpreg_vmstate_indexes[v] < cpu->cpreg_indexes[i]) { - g_autofree gchar *name =3D print_register_name(cpu->cpreg_vmst= ate_indexes[v]); - - error_report("%s: %s in the incoming stream but unknown on the= destination, " - "fail migration", __func__, name); - v++; - fail =3D true; + fail =3D handle_cpreg_only_in_incoming_stream(cpu, + cpu->cpreg_vmstate= _indexes[v++]); continue; } /* matching register, copy the value over */ @@ -1113,22 +1143,15 @@ static int cpu_post_load(void *opaque, int version_= id) * in the input stream */ for ( ; i < cpu->cpreg_array_len; i++) { - g_autofree gchar *name =3D print_register_name(cpu->cpreg_indexes[= i]); - - warn_report("%s: %s " - "expected by the destination but not in the incoming s= tream, " - "skip it", __func__, name); + handle_cpreg_missing_in_incoming_stream(cpu, cpu->cpreg_indexes[i]= ); } /* * if we have reached the end of the cpreg array but there are * still regs in the input stream, continue parsing the vmstate array */ for ( ; v < cpu->cpreg_vmstate_array_len; v++) { - g_autofree gchar *name =3D print_register_name(cpu->cpreg_vmstate_= indexes[v]); - - error_report("%s: %s in the incoming stream but unknown on the des= tination, " - "fail migration", __func__, name); - fail =3D true; + fail =3D handle_cpreg_only_in_incoming_stream(cpu, + cpu->cpreg_vmstate_ind= exes[v]); } if (fail) { return -1; diff --git a/target/arm/trace-events b/target/arm/trace-events index 2de0406f784..dceb3c63f77 100644 --- a/target/arm/trace-events +++ b/target/arm/trace-events @@ -29,3 +29,5 @@ arm_psci_call(uint64_t x0, uint64_t x1, uint64_t x2, uint= 64_t x3, uint32_t cpuid =20 # machine.c cpu_post_load(uint32_t cpreg_vmstate_array_len, uint32_t cpreg_array_len) = "cpreg_vmstate_array_len=3D%d cpreg_array_len=3D%d" +tolerate_cpreg_missing_in_incoming_stream(char *name) "cpreg %s is missing= in incoming stream but this is explicitly tolerated" +tolerate_cpreg_only_in_incoming_stream(char *name) "cpreg %s is in incomin= g stream but not on destination but this is explicitly tolerated" --=20 2.53.0