{"id":2223043,"url":"http://patchwork.ozlabs.org/api/patches/2223043/?format=json","web_url":"http://patchwork.ozlabs.org/project/qemu-devel/patch/20260414082915.112122-7-armenon@redhat.com/","project":{"id":14,"url":"http://patchwork.ozlabs.org/api/projects/14/?format=json","name":"QEMU Development","link_name":"qemu-devel","list_id":"qemu-devel.nongnu.org","list_email":"qemu-devel@nongnu.org","web_url":"","scm_url":"","webscm_url":"","list_archive_url":"","list_archive_url_format":"","commit_url_format":""},"msgid":"<20260414082915.112122-7-armenon@redhat.com>","list_archive_url":null,"date":"2026-04-14T08:29:11","name":"[v4,06/10] hw/tpm: Add support for VM migration with TPM CRB chunking","commit_ref":null,"pull_url":null,"state":"new","archived":false,"hash":"a977fa867fb1a25fbeb1d487c82dd26f75e295b2","submitter":{"id":91136,"url":"http://patchwork.ozlabs.org/api/people/91136/?format=json","name":"Arun Menon","email":"armenon@redhat.com"},"delegate":null,"mbox":"http://patchwork.ozlabs.org/project/qemu-devel/patch/20260414082915.112122-7-armenon@redhat.com/mbox/","series":[{"id":499802,"url":"http://patchwork.ozlabs.org/api/series/499802/?format=json","web_url":"http://patchwork.ozlabs.org/project/qemu-devel/list/?series=499802","date":"2026-04-14T08:29:05","name":"hw/tpm: CRB chunking capability to handle PQC","version":4,"mbox":"http://patchwork.ozlabs.org/series/499802/mbox/"}],"comments":"http://patchwork.ozlabs.org/api/patches/2223043/comments/","check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/2223043/checks/","tags":{},"related":[],"headers":{"Return-Path":"","X-Original-To":"incoming@patchwork.ozlabs.org","Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (1024-bit key;\n unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256\n header.s=mimecast20190719 header.b=XDOobnf0;\n\tdkim=pass (2048-bit key;\n unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256\n header.s=google header.b=f0klhg5W;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org\n (client-ip=209.51.188.17; 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Tsirkin\" , =?utf-8?q?Philippe_Mathieu-Daud?=\n\t=?utf-8?q?=C3=A9?= ,\n Stefan Berger ,\n Paolo Bonzini ,\n Marcel Apfelbaum ,\n Zhao Liu , marcandre.lureau@redhat.com,\n Igor Mammedov , Laurent Vivier ,\n Fabiano Rosas , Arun Menon ","Subject":"[PATCH v4 06/10] hw/tpm: Add support for VM migration with TPM CRB\n chunking","Date":"Tue, 14 Apr 2026 13:59:11 +0530","Message-ID":"<20260414082915.112122-7-armenon@redhat.com>","X-Mailer":"git-send-email 2.53.0","In-Reply-To":"<20260414082915.112122-1-armenon@redhat.com>","References":"<20260414082915.112122-1-armenon@redhat.com>","MIME-Version":"1.0","Content-Transfer-Encoding":"8bit","Received-SPF":"pass client-ip=170.10.133.124; envelope-from=armenon@redhat.com;\n helo=us-smtp-delivery-124.mimecast.com","X-Spam_score_int":"-25","X-Spam_score":"-2.6","X-Spam_bar":"--","X-Spam_report":"(-2.6 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.54,\n DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1,\n RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=0.001,\n RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.001,\n SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=ham 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":",\n ","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n ","Errors-To":"qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org","Sender":"qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org"},"content":"From: Arun Menon \n\n- Add subsection in VMState for TPM CRB with the newly introduced\n command and response buffer GByteArrays, along with a needed callback,\n so that newer QEMU only sends the buffers if it is necessary.\n- Add hw_compat global properties for both migrate-buffers and cap-chunk\n because the chunking feature is only supported for machine type 11.1\n and higher.\n- Implement a migration blocker to prevent migration of the VM if the\n user manually enables chunking capability but disables buffer\n migration. This avoids state data loss.\n\nSigned-off-by: Arun Menon \n---\n hw/core/machine.c | 5 ++++-\n hw/tpm/tpm_crb.c | 53 ++++++++++++++++++++++++++++++++++++++++++++++-\n 2 files changed, 56 insertions(+), 2 deletions(-)","diff":"diff --git a/hw/core/machine.c b/hw/core/machine.c\nindex 1abc8ae737..6d6b0fc9d1 100644\n--- a/hw/core/machine.c\n+++ b/hw/core/machine.c\n@@ -38,7 +38,10 @@\n #include \"hw/acpi/generic_event_device.h\"\n #include \"qemu/audio.h\"\n \n-GlobalProperty hw_compat_11_0[] = {};\n+GlobalProperty hw_compat_11_0[] = {\n+ { \"tpm-crb\", \"x-migrate-buffers\", \"off\"},\n+ { \"tpm-crb\", \"x-cap-chunk\", \"off\"},\n+};\n const size_t hw_compat_11_0_len = G_N_ELEMENTS(hw_compat_11_0);\n \n GlobalProperty hw_compat_10_2[] = {\ndiff --git a/hw/tpm/tpm_crb.c b/hw/tpm/tpm_crb.c\nindex 8e44df1aed..0f1eced977 100644\n--- a/hw/tpm/tpm_crb.c\n+++ b/hw/tpm/tpm_crb.c\n@@ -24,6 +24,7 @@\n #include \"hw/pci/pci_ids.h\"\n #include \"hw/acpi/tpm.h\"\n #include \"migration/vmstate.h\"\n+#include \"migration/blocker.h\"\n #include \"system/tpm_backend.h\"\n #include \"system/tpm_util.h\"\n #include \"system/reset.h\"\n@@ -49,6 +50,10 @@ struct CRBState {\n \n bool ppi_enabled;\n TPMPPI ppi;\n+\n+ bool migrate_buffers;\n+ bool cap_chunk;\n+ Error *migration_blocker;\n };\n typedef struct CRBState CRBState;\n \n@@ -345,18 +350,48 @@ static int tpm_crb_pre_save(void *opaque)\n return 0;\n }\n \n+static bool tpm_crb_chunk_needed(void *opaque)\n+{\n+ CRBState *s = opaque;\n+\n+ if (!s->migrate_buffers) {\n+ return false;\n+ }\n+\n+ return ((s->command_buffer && s->command_buffer->len > 0) ||\n+ (s->response_buffer && s->response_buffer->len > 0));\n+}\n+\n+static const VMStateDescription vmstate_tpm_crb_chunk = {\n+ .name = \"tpm-crb/chunk\",\n+ .version_id = 0,\n+ .needed = tpm_crb_chunk_needed,\n+ .fields = (const VMStateField[]) {\n+ VMSTATE_GBYTEARRAY(command_buffer, CRBState, 0),\n+ VMSTATE_GBYTEARRAY(response_buffer, CRBState, 0),\n+ VMSTATE_UINT32(response_offset, CRBState),\n+ VMSTATE_END_OF_LIST()\n+ }\n+};\n+\n static const VMStateDescription vmstate_tpm_crb = {\n .name = \"tpm-crb\",\n .pre_save = tpm_crb_pre_save,\n .fields = (const VMStateField[]) {\n VMSTATE_UINT32_ARRAY(regs, CRBState, TPM_CRB_R_MAX),\n VMSTATE_END_OF_LIST(),\n+ },\n+ .subsections = (const VMStateDescription * const []) {\n+ &vmstate_tpm_crb_chunk,\n+ NULL,\n }\n };\n \n static const Property tpm_crb_properties[] = {\n DEFINE_PROP_TPMBE(\"tpmdev\", CRBState, tpmbe),\n DEFINE_PROP_BOOL(\"ppi\", CRBState, ppi_enabled, true),\n+ DEFINE_PROP_BOOL(\"x-migrate-buffers\", CRBState, migrate_buffers, true),\n+ DEFINE_PROP_BOOL(\"x-cap-chunk\", CRBState, cap_chunk, true),\n };\n \n static void tpm_crb_reset(void *dev)\n@@ -392,7 +427,7 @@ static void tpm_crb_reset(void *dev)\n ARRAY_FIELD_DP32(s->regs, CRB_INTF_ID,\n InterfaceSelector, CRB_INTF_IF_SELECTOR_CRB);\n ARRAY_FIELD_DP32(s->regs, CRB_INTF_ID,\n- CapCRBChunk, CRB_INTF_CAP_CRB_CHUNK);\n+ CapCRBChunk, s->cap_chunk ? CRB_INTF_CAP_CRB_CHUNK : 0);\n ARRAY_FIELD_DP32(s->regs, CRB_INTF_ID,\n RID, 0b0000);\n ARRAY_FIELD_DP32(s->regs, CRB_INTF_ID2,\n@@ -413,6 +448,7 @@ static void tpm_crb_reset(void *dev)\n static void tpm_crb_realize(DeviceState *dev, Error **errp)\n {\n CRBState *s = CRB(dev);\n+ int ret;\n \n if (!tpm_find()) {\n error_setg(errp, \"at most one TPM device is permitted\");\n@@ -422,6 +458,16 @@ static void tpm_crb_realize(DeviceState *dev, Error **errp)\n error_setg(errp, \"'tpmdev' property is required\");\n return;\n }\n+ if (s->cap_chunk && !s->migrate_buffers) {\n+ error_setg(&s->migration_blocker, \"TPM chunking is enabled but \"\n+ \"buffer migration is disabled. Migration is blocked to prevent \"\n+ \"data loss\");\n+\n+ ret = migrate_add_blocker_normal(&s->migration_blocker, errp);\n+ if (ret < 0) {\n+ return;\n+ }\n+ }\n \n memory_region_init_io(&s->mmio, OBJECT(s), &tpm_crb_memory_ops, s,\n \"tpm-crb-mmio\", sizeof(s->regs));\n@@ -454,6 +500,11 @@ static void tpm_crb_unrealize(DeviceState *dev)\n \n g_clear_pointer(&s->command_buffer, g_byte_array_unref);\n g_clear_pointer(&s->response_buffer, g_byte_array_unref);\n+\n+ if (s->migration_blocker) {\n+ migrate_del_blocker(&s->migration_blocker);\n+ error_free(s->migration_blocker);\n+ }\n }\n \n static void tpm_crb_class_init(ObjectClass *klass, const void *data)\n","prefixes":["v4","06/10"]}