From cfcde3507dd742c0e17cdfe3ac3bf076cc131a84 Mon Sep 17 00:00:00 2001 From: Leonardo Bras Date: Tue, 19 Jul 2022 09:23:45 -0300 Subject: [PATCH 32/34] migration: Avoid false-positive on non-supported scenarios for zero-copy-send MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit RH-Author: Leonardo Brás RH-MergeRequest: 185: MSG_ZEROCOPY + Multifd @ rhel8.6 RH-Commit: [32/34] 409d9f974c5d69cdb4df8ef44f45c6cb25638144 RH-Bugzilla: 2117252 RH-Acked-by: quintela1 RH-Acked-by: Dr. David Alan Gilbert RH-Acked-by: Peter Xu Migration with zero-copy-send currently has it's limitations, as it can't be used with TLS nor any kind of compression. In such scenarios, it should output errors during parameter / capability setting. But currently there are some ways of setting this not-supported scenarios without printing the error message: !) For 'compression' capability, it works by enabling it together with zero-copy-send. This happens because the validity test for zero-copy uses the helper unction migrate_use_compression(), which check for compression presence in s->enabled_capabilities[MIGRATION_CAPABILITY_COMPRESS]. The point here is: the validity test happens before the capability gets enabled. If all of them get enabled together, this test will not return error. In order to fix that, replace migrate_use_compression() by directly testing the cap_list parameter migrate_caps_check(). 2) For features enabled by parameters such as TLS & 'multifd_compression', there was also a possibility of setting non-supported scenarios: setting zero-copy-send first, then setting the unsupported parameter. In order to fix that, also add a check for parameters conflicting with zero-copy-send on migrate_params_check(). 3) XBZRLE is also a compression capability, so it makes sense to also add it to the list of capabilities which are not supported with zero-copy-send. Fixes: 1abaec9a1b2c ("migration: Change zero_copy_send from migration parameter to migration capability") Signed-off-by: Leonardo Bras Message-Id: <20220719122345.253713-1-leobras@redhat.com> Reviewed-by: Dr. David Alan Gilbert Signed-off-by: Dr. David Alan Gilbert (cherry picked from commit 90eb69e4f1a16b388d0483543bf6bfc69a9966e4) Signed-off-by: Leonardo Bras --- migration/migration.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-) diff --git a/migration/migration.c b/migration/migration.c index a3e0ac954c..b1fe50a749 100644 --- a/migration/migration.c +++ b/migration/migration.c @@ -1254,7 +1254,9 @@ static bool migrate_caps_check(bool *cap_list, #ifdef CONFIG_LINUX if (cap_list[MIGRATION_CAPABILITY_ZERO_COPY_SEND] && (!cap_list[MIGRATION_CAPABILITY_MULTIFD] || - migrate_use_compression() || + cap_list[MIGRATION_CAPABILITY_COMPRESS] || + cap_list[MIGRATION_CAPABILITY_XBZRLE] || + migrate_multifd_compression() || migrate_use_tls())) { error_setg(errp, "Zero copy only available for non-compressed non-TLS multifd migration"); @@ -1491,6 +1493,17 @@ static bool migrate_params_check(MigrationParameters *params, Error **errp) error_prepend(errp, "Invalid mapping given for block-bitmap-mapping: "); return false; } + +#ifdef CONFIG_LINUX + if (migrate_use_zero_copy_send() && + ((params->has_multifd_compression && params->multifd_compression) || + (params->has_tls_creds && params->tls_creds && *params->tls_creds))) { + error_setg(errp, + "Zero copy only available for non-compressed non-TLS multifd migration"); + return false; + } +#endif + return true; } -- 2.35.3