94 lines
3.1 KiB
Diff
94 lines
3.1 KiB
Diff
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From d1c6d059f8936adf7b8c3e2b29b2eb290b0792ac Mon Sep 17 00:00:00 2001
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From: Peter Xu <peterx@redhat.com>
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Date: Wed, 22 Sep 2021 12:20:09 -0400
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Subject: [PATCH 3/6] dump-guest-memory: Block live migration
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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RH-Author: Peter Xu <peterx@redhat.com>
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RH-MergeRequest: 51: dump-guest-memory: Add blocker for migration
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RH-Commit: [3/3] 711dcc0018f70bcb87496c5aa235633a6daf5c2d (peterx/qemu-kvm)
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RH-Bugzilla: 1996609
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RH-Acked-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
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RH-Acked-by: quintela1 <quintela@redhat.com>
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RH-Acked-by: Laszlo Ersek <lersek@redhat.com>
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Both dump-guest-memory and live migration caches vm state at the beginning.
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Either of them entering the other one will cause race on the vm state, and even
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more severe on that (please refer to the crash report in the bug link).
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Let's block live migration in dump-guest-memory, and that'll also block
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dump-guest-memory if it detected that we're during a live migration.
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Side note: migrate_del_blocker() can be called even if the blocker is not
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inserted yet, so it's safe to unconditionally delete that blocker in
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dump_cleanup (g_slist_remove allows no-entry-found case).
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Suggested-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
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Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1996609
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Signed-off-by: Peter Xu <peterx@redhat.com>
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Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
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Reviewed-by: Juan Quintela <quintela@redhat.com>
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Signed-off-by: Juan Quintela <quintela@redhat.com>
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(cherry picked from commit b7bc6b182883bb3097dde2a25d041f28bde2b89c)
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Signed-off-by: Peter Xu <peterx@redhat.com>
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---
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dump/dump.c | 19 +++++++++++++++++++
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1 file changed, 19 insertions(+)
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diff --git a/dump/dump.c b/dump/dump.c
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index ab625909f3..662d0a62cd 100644
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--- a/dump/dump.c
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+++ b/dump/dump.c
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@@ -29,6 +29,7 @@
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#include "qemu/error-report.h"
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#include "qemu/main-loop.h"
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#include "hw/misc/vmcoreinfo.h"
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+#include "migration/blocker.h"
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#ifdef TARGET_X86_64
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#include "win_dump.h"
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@@ -47,6 +48,8 @@
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#define MAX_GUEST_NOTE_SIZE (1 << 20) /* 1MB should be enough */
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+static Error *dump_migration_blocker;
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+
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#define ELF_NOTE_SIZE(hdr_size, name_size, desc_size) \
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((DIV_ROUND_UP((hdr_size), 4) + \
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DIV_ROUND_UP((name_size), 4) + \
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@@ -101,6 +104,7 @@ static int dump_cleanup(DumpState *s)
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qemu_mutex_unlock_iothread();
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}
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}
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+ migrate_del_blocker(dump_migration_blocker);
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return 0;
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}
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@@ -2005,6 +2009,21 @@ void qmp_dump_guest_memory(bool paging, const char *file,
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return;
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}
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+ if (!dump_migration_blocker) {
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+ error_setg(&dump_migration_blocker,
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+ "Live migration disabled: dump-guest-memory in progress");
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+ }
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+
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+ /*
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+ * Allows even for -only-migratable, but forbid migration during the
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+ * process of dump guest memory.
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+ */
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+ if (migrate_add_blocker_internal(dump_migration_blocker, errp)) {
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+ /* Remember to release the fd before passing it over to dump state */
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+ close(fd);
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+ return;
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+ }
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+
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s = &dump_state_global;
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dump_state_prepare(s);
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--
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2.27.0
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