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[70.52.229.124]) by smtp.gmail.com with ESMTPSA id t12-20020a05620a0b0c00b007468b183a65sm351481qkg.30.2023.04.19.09.17.49 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 19 Apr 2023 09:17:49 -0700 (PDT) From: Peter Xu To: qemu-devel@nongnu.org Cc: Paolo Bonzini , peterx@redhat.com, =?utf-8?q?Daniel?= =?utf-8?q?_P_=2E_Berrang=C3=A9?= , Juan Quintela , Leonardo Bras Soares Passos , David Hildenbrand Subject: [PATCH v2 4/4] migration: Allow postcopy_ram_supported_by_host() to report err Date: Wed, 19 Apr 2023 12:17:39 -0400 Message-Id: <20230419161739.1129988-5-peterx@redhat.com> X-Mailer: git-send-email 2.39.1 In-Reply-To: <20230419161739.1129988-1-peterx@redhat.com> References: <20230419161739.1129988-1-peterx@redhat.com> MIME-Version: 1.0 Received-SPF: pass client-ip=170.10.133.124; envelope-from=peterx@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 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_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 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: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Instead of print it to STDERR, bring the error upwards so that it can be reported via QMP responses. E.g.: { "execute": "migrate-set-capabilities" , "arguments": { "capabilities": [ { "capability": "postcopy-ram", "state": true } ] } } { "error": { "class": "GenericError", "desc": "Postcopy is not supported: Host backend files need to be TMPFS or HUGETLBFS only" } } Signed-off-by: Peter Xu --- migration/migration.c | 9 +++--- migration/postcopy-ram.c | 61 ++++++++++++++++++++++------------------ migration/postcopy-ram.h | 3 +- migration/savevm.c | 3 +- 4 files changed, 42 insertions(+), 34 deletions(-) diff --git a/migration/migration.c b/migration/migration.c index bda4789193..ac15fa6092 100644 --- a/migration/migration.c +++ b/migration/migration.c @@ -1313,6 +1313,7 @@ static bool migrate_caps_check(bool *cap_list, MigrationCapabilityStatusList *cap; bool old_postcopy_cap; MigrationIncomingState *mis = migration_incoming_get_current(); + Error *local_err = NULL; old_postcopy_cap = cap_list[MIGRATION_CAPABILITY_POSTCOPY_RAM]; @@ -1344,11 +1345,9 @@ static bool migrate_caps_check(bool *cap_list, * special support. */ if (!old_postcopy_cap && runstate_check(RUN_STATE_INMIGRATE) && - !postcopy_ram_supported_by_host(mis)) { - /* postcopy_ram_supported_by_host will have emitted a more - * detailed message - */ - error_setg(errp, "Postcopy is not supported"); + !postcopy_ram_supported_by_host(mis, &local_err)) { + error_propagate_prepend(errp, local_err, + "Postcopy is not supported: "); return false; } diff --git a/migration/postcopy-ram.c b/migration/postcopy-ram.c index bbb8af61ae..0713ddeeef 100644 --- a/migration/postcopy-ram.c +++ b/migration/postcopy-ram.c @@ -282,11 +282,14 @@ static bool request_ufd_features(int ufd, uint64_t features) return true; } -static bool ufd_check_and_apply(int ufd, MigrationIncomingState *mis) +static bool ufd_check_and_apply(int ufd, MigrationIncomingState *mis, + Error **errp) { uint64_t asked_features = 0; static uint64_t supported_features; + assert(errp); + /* * it's not possible to * request UFFD_API twice per one fd @@ -294,7 +297,7 @@ static bool ufd_check_and_apply(int ufd, MigrationIncomingState *mis) */ if (!supported_features) { if (!receive_ufd_features(&supported_features)) { - error_report("%s failed", __func__); + error_setg(errp, "Userfault feature detection failed"); return false; } } @@ -316,8 +319,7 @@ static bool ufd_check_and_apply(int ufd, MigrationIncomingState *mis) * userfault file descriptor */ if (!request_ufd_features(ufd, asked_features)) { - error_report("%s failed: features %" PRIu64, __func__, - asked_features); + error_setg(errp, "Failed features %" PRIu64, asked_features); return false; } @@ -328,7 +330,8 @@ static bool ufd_check_and_apply(int ufd, MigrationIncomingState *mis) have_hp = supported_features & UFFD_FEATURE_MISSING_HUGETLBFS; #endif if (!have_hp) { - error_report("Userfault on this host does not support huge pages"); + error_setg(errp, + "Userfault on this host does not support huge pages"); return false; } } @@ -337,7 +340,7 @@ static bool ufd_check_and_apply(int ufd, MigrationIncomingState *mis) /* Callback from postcopy_ram_supported_by_host block iterator. */ -static int test_ramblock_postcopiable(RAMBlock *rb) +static int test_ramblock_postcopiable(RAMBlock *rb, Error **errp) { const char *block_name = qemu_ram_get_idstr(rb); ram_addr_t length = qemu_ram_get_used_length(rb); @@ -345,16 +348,18 @@ static int test_ramblock_postcopiable(RAMBlock *rb) QemuFsType fs; if (length % pagesize) { - error_report("Postcopy requires RAM blocks to be a page size multiple," - " block %s is 0x" RAM_ADDR_FMT " bytes with a " - "page size of 0x%zx", block_name, length, pagesize); + error_setg(errp, + "Postcopy requires RAM blocks to be a page size multiple," + " block %s is 0x" RAM_ADDR_FMT " bytes with a " + "page size of 0x%zx", block_name, length, pagesize); return 1; } if (rb->fd >= 0) { fs = qemu_fd_getfs(rb->fd); if (fs != QEMU_FS_TYPE_TMPFS && fs != QEMU_FS_TYPE_HUGETLBFS) { - error_report("Host backend files need to be TMPFS or HUGETLBFS only"); + error_setg(errp, + "Host backend files need to be TMPFS or HUGETLBFS only"); return 1; } } @@ -367,7 +372,8 @@ static int test_ramblock_postcopiable(RAMBlock *rb) * normally fine since if the postcopy succeeds it gets turned back on at the * end. */ -bool postcopy_ram_supported_by_host(MigrationIncomingState *mis) +bool postcopy_ram_supported_by_host(MigrationIncomingState *mis, + Error **errp) { long pagesize = qemu_real_host_page_size(); int ufd = -1; @@ -376,29 +382,28 @@ bool postcopy_ram_supported_by_host(MigrationIncomingState *mis) struct uffdio_register reg_struct; struct uffdio_range range_struct; uint64_t feature_mask; - Error *local_err = NULL; RAMBlock *block; + assert(errp); + if (qemu_target_page_size() > pagesize) { - error_report("Target page size bigger than host page size"); + error_setg(errp, "Target page size bigger than host page size"); goto out; } ufd = uffd_open(O_CLOEXEC); if (ufd == -1) { - error_report("%s: userfaultfd not available: %s", __func__, - strerror(errno)); + error_setg(errp, "Userfaultfd not available: %s", strerror(errno)); goto out; } /* Give devices a chance to object */ - if (postcopy_notify(POSTCOPY_NOTIFY_PROBE, &local_err)) { - error_report_err(local_err); + if (postcopy_notify(POSTCOPY_NOTIFY_PROBE, errp)) { goto out; } /* Version and features check */ - if (!ufd_check_and_apply(ufd, mis)) { + if (!ufd_check_and_apply(ufd, mis, errp)) { goto out; } @@ -416,7 +421,7 @@ bool postcopy_ram_supported_by_host(MigrationIncomingState *mis) * affect in reality, or we can revisit. */ RAMBLOCK_FOREACH(block) { - if (test_ramblock_postcopiable(block)) { + if (test_ramblock_postcopiable(block, errp)) { goto out; } } @@ -426,7 +431,7 @@ bool postcopy_ram_supported_by_host(MigrationIncomingState *mis) * it was enabled. */ if (munlockall()) { - error_report("%s: munlockall: %s", __func__, strerror(errno)); + error_setg(errp, "munlockall() failed: %s", strerror(errno)); goto out; } @@ -438,8 +443,7 @@ bool postcopy_ram_supported_by_host(MigrationIncomingState *mis) testarea = mmap(NULL, pagesize, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); if (testarea == MAP_FAILED) { - error_report("%s: Failed to map test area: %s", __func__, - strerror(errno)); + error_setg(errp, "Failed to map test area: %s", strerror(errno)); goto out; } g_assert(QEMU_PTR_IS_ALIGNED(testarea, pagesize)); @@ -449,14 +453,14 @@ bool postcopy_ram_supported_by_host(MigrationIncomingState *mis) reg_struct.mode = UFFDIO_REGISTER_MODE_MISSING; if (ioctl(ufd, UFFDIO_REGISTER, ®_struct)) { - error_report("%s userfault register: %s", __func__, strerror(errno)); + error_setg(errp, "UFFDIO_REGISTER failed: %s", strerror(errno)); goto out; } range_struct.start = (uintptr_t)testarea; range_struct.len = pagesize; if (ioctl(ufd, UFFDIO_UNREGISTER, &range_struct)) { - error_report("%s userfault unregister: %s", __func__, strerror(errno)); + error_setg(errp, "UFFDIO_UNREGISTER failed: %s", strerror(errno)); goto out; } @@ -464,8 +468,8 @@ bool postcopy_ram_supported_by_host(MigrationIncomingState *mis) (__u64)1 << _UFFDIO_COPY | (__u64)1 << _UFFDIO_ZEROPAGE; if ((reg_struct.ioctls & feature_mask) != feature_mask) { - error_report("Missing userfault map features: %" PRIx64, - (uint64_t)(~reg_struct.ioctls & feature_mask)); + error_setg(errp, "Missing userfault map features: %" PRIx64, + (uint64_t)(~reg_struct.ioctls & feature_mask)); goto out; } @@ -1187,6 +1191,8 @@ static int postcopy_temp_pages_setup(MigrationIncomingState *mis) int postcopy_ram_incoming_setup(MigrationIncomingState *mis) { + Error *local_err = NULL; + /* Open the fd for the kernel to give us userfaults */ mis->userfault_fd = uffd_open(O_CLOEXEC | O_NONBLOCK); if (mis->userfault_fd == -1) { @@ -1199,7 +1205,8 @@ int postcopy_ram_incoming_setup(MigrationIncomingState *mis) * Although the host check already tested the API, we need to * do the check again as an ABI handshake on the new fd. */ - if (!ufd_check_and_apply(mis->userfault_fd, mis)) { + if (!ufd_check_and_apply(mis->userfault_fd, mis, &local_err)) { + error_report_err(local_err); return -1; } diff --git a/migration/postcopy-ram.h b/migration/postcopy-ram.h index b4867a32d5..442ab89752 100644 --- a/migration/postcopy-ram.h +++ b/migration/postcopy-ram.h @@ -14,7 +14,8 @@ #define QEMU_POSTCOPY_RAM_H /* Return true if the host supports everything we need to do postcopy-ram */ -bool postcopy_ram_supported_by_host(MigrationIncomingState *mis); +bool postcopy_ram_supported_by_host(MigrationIncomingState *mis, + Error **errp); /* * Make all of RAM sensitive to accesses to areas that haven't yet been written diff --git a/migration/savevm.c b/migration/savevm.c index aa54a67fda..0d61ab6c19 100644 --- a/migration/savevm.c +++ b/migration/savevm.c @@ -1752,7 +1752,8 @@ static int loadvm_postcopy_handle_advise(MigrationIncomingState *mis, return -EINVAL; } - if (!postcopy_ram_supported_by_host(mis)) { + if (!postcopy_ram_supported_by_host(mis, &local_err)) { + error_report_err(local_err); postcopy_state_set(POSTCOPY_INCOMING_NONE); return -1; }