From: Catherine Ho <catherine.hecx@gmail.com> To: Paolo Bonzini <pbonzini@redhat.com>, Richard Henderson <rth@twiddle.net>, "Dr. David Alan Gilbert" <dgilbert@redhat.com> Cc: Markus Armbruster <armbru@redhat.com>, Juan Quintela <quintela@redhat.com>, qemu-devel@nongnu.org, Peter Xu <peterx@redhat.com>, Catherine Ho <catherine.hecx@gmail.com> Subject: [Qemu-devel] [PATCH v3] migration: do not rom_reset() during incoming migration Date: Sun, 7 Apr 2019 21:56:56 -0400 [thread overview] Message-ID: <1554688616-18583-1-git-send-email-catherine.hecx@gmail.com> (raw) Commit 18269069c310 ("migration: Introduce ignore-shared capability") addes ignore-shared capability to bypass the shared ramblock (e,g, membackend + numa node). It does good to live migration. As told by Yury,this commit expectes that QEMU doesn't write to guest RAM until VM starts, but it does on aarch64 qemu: Backtrace: 1 0x000055f4a296dd84 in address_space_write_rom_internal () at exec.c:3458 2 0x000055f4a296de3a in address_space_write_rom () at exec.c:3479 3 0x000055f4a2d519ff in rom_reset () at hw/core/loader.c:1101 4 0x000055f4a2d475ec in qemu_devices_reset () at hw/core/reset.c:69 5 0x000055f4a2c90a28 in qemu_system_reset () at vl.c:1675 6 0x000055f4a2c9851d in main () at vl.c:4552 Actually, on arm64 virt marchine, ramblock "dtb" will be filled into ram druing rom_reset. In ignore-shared incoming case, this rom filling is not required since all the data has been stored in memory backend file. Further more, as suggested by Peter Xu, if we do rom_reset() now with these ROMs then the RAM data should be re-filled again too with the migration stream coming in. Fixes: commit 18269069c310 ("migration: Introduce ignore-shared capability") Suggested-by: Yury Kotov <yury-kotov@yandex-team.ru> Suggested-by: Peter Xu <peterx@redhat.com> Signed-off-by: Catherine Ho <catherine.hecx@gmail.com> --- hw/core/loader.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/hw/core/loader.c b/hw/core/loader.c index fe5cb24122..946bb8ff00 100644 --- a/hw/core/loader.c +++ b/hw/core/loader.c @@ -1087,6 +1087,13 @@ static void rom_reset(void *unused) { Rom *rom; + /* + * If we do rom_reset() now with these ROMs then the RAM data should be + * re-filled again too with the migration stream coming in. + */ + if (runstate_check(RUN_STATE_INMIGRATE)) + return; + QTAILQ_FOREACH(rom, &roms, next) { if (rom->fw_file) { continue; -- 2.17.1
WARNING: multiple messages have this Message-ID (diff)
From: Catherine Ho <catherine.hecx@gmail.com> To: Paolo Bonzini <pbonzini@redhat.com>, Richard Henderson <rth@twiddle.net>, "Dr. David Alan Gilbert" <dgilbert@redhat.com> Cc: qemu-devel@nongnu.org, Catherine Ho <catherine.hecx@gmail.com>, Markus Armbruster <armbru@redhat.com>, Peter Xu <peterx@redhat.com>, Juan Quintela <quintela@redhat.com> Subject: [Qemu-devel] [PATCH v3] migration: do not rom_reset() during incoming migration Date: Sun, 7 Apr 2019 21:56:56 -0400 [thread overview] Message-ID: <1554688616-18583-1-git-send-email-catherine.hecx@gmail.com> (raw) Message-ID: <20190408015656.SjMbI6AL5jMdtzP7RP8a2C-JlVLeYnGKdMIBVkT8bNw@z> (raw) Commit 18269069c310 ("migration: Introduce ignore-shared capability") addes ignore-shared capability to bypass the shared ramblock (e,g, membackend + numa node). It does good to live migration. As told by Yury,this commit expectes that QEMU doesn't write to guest RAM until VM starts, but it does on aarch64 qemu: Backtrace: 1 0x000055f4a296dd84 in address_space_write_rom_internal () at exec.c:3458 2 0x000055f4a296de3a in address_space_write_rom () at exec.c:3479 3 0x000055f4a2d519ff in rom_reset () at hw/core/loader.c:1101 4 0x000055f4a2d475ec in qemu_devices_reset () at hw/core/reset.c:69 5 0x000055f4a2c90a28 in qemu_system_reset () at vl.c:1675 6 0x000055f4a2c9851d in main () at vl.c:4552 Actually, on arm64 virt marchine, ramblock "dtb" will be filled into ram druing rom_reset. In ignore-shared incoming case, this rom filling is not required since all the data has been stored in memory backend file. Further more, as suggested by Peter Xu, if we do rom_reset() now with these ROMs then the RAM data should be re-filled again too with the migration stream coming in. Fixes: commit 18269069c310 ("migration: Introduce ignore-shared capability") Suggested-by: Yury Kotov <yury-kotov@yandex-team.ru> Suggested-by: Peter Xu <peterx@redhat.com> Signed-off-by: Catherine Ho <catherine.hecx@gmail.com> --- hw/core/loader.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/hw/core/loader.c b/hw/core/loader.c index fe5cb24122..946bb8ff00 100644 --- a/hw/core/loader.c +++ b/hw/core/loader.c @@ -1087,6 +1087,13 @@ static void rom_reset(void *unused) { Rom *rom; + /* + * If we do rom_reset() now with these ROMs then the RAM data should be + * re-filled again too with the migration stream coming in. + */ + if (runstate_check(RUN_STATE_INMIGRATE)) + return; + QTAILQ_FOREACH(rom, &roms, next) { if (rom->fw_file) { continue; -- 2.17.1
next reply other threads:[~2019-04-08 1:58 UTC|newest] Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-04-08 1:56 Catherine Ho [this message] 2019-04-08 1:56 ` [Qemu-devel] [PATCH v3] migration: do not rom_reset() during incoming migration Catherine Ho 2019-04-08 3:31 ` Peter Xu 2019-04-08 3:31 ` Peter Xu 2019-04-08 8:42 ` [Qemu-devel] [PATCH v4] " Catherine Ho 2019-04-08 8:42 ` Catherine Ho 2019-04-16 1:46 ` Catherine Ho 2019-04-16 1:46 ` Catherine Ho 2019-04-16 2:51 ` Peter Xu 2019-04-16 2:51 ` Peter Xu 2019-05-13 3:00 ` Catherine Ho 2019-06-05 18:31 ` Dr. David Alan Gilbert 2019-08-14 10:40 ` Catherine Ho 2019-08-14 12:34 ` Paolo Bonzini
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