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author | Philippe Mathieu-Daudé <f4bug@amsat.org> | 2021-05-17 12:51:29 +0200 |
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committer | Richard Henderson <richard.henderson@linaro.org> | 2021-05-26 15:33:59 -0700 |
commit | 744c72a837a0428f2d5373793e42aba963bf47c6 (patch) | |
tree | 71e0ed96c8c8f0200ce481d5fe7006c7ba03f9b3 /target/riscv/cpu.c | |
parent | 4336073b9b13943e050edfe9aebb99974c3b6ee1 (diff) | |
download | qemu-744c72a837a0428f2d5373793e42aba963bf47c6.zip qemu-744c72a837a0428f2d5373793e42aba963bf47c6.tar.gz qemu-744c72a837a0428f2d5373793e42aba963bf47c6.tar.bz2 |
cpu: Rename CPUClass vmsd -> legacy_vmsd
Quoting Peter Maydell [*]:
There are two ways to handle migration for
a CPU object:
(1) like any other device, so it has a dc->vmsd that covers
migration for the whole object. As usual for objects that are a
subclass of a parent that has state, the first entry in the
VMStateDescription field list is VMSTATE_CPU(), which migrates
the cpu_common fields, followed by whatever the CPU's own migration
fields are.
(2) a backwards-compatible mechanism for CPUs that were
originally migrated using manual "write fields to the migration
stream structures". The on-the-wire migration format
for those is based on the 'env' pointer (which isn't a QOM object),
and the cpu_common part of the migration data is elsewhere.
cpu_exec_realizefn() handles both possibilities:
* for type 1, dc->vmsd is set and cc->vmsd is not,
so cpu_exec_realizefn() does nothing, and the standard
"register dc->vmsd for a device" code does everything needed
* for type 2, dc->vmsd is NULL and so we register the
vmstate_cpu_common directly to handle the cpu-common fields,
and the cc->vmsd to handle the per-CPU stuff
You can't change a CPU from one type to the other without breaking
migration compatibility, which is why some guest architectures
are stuck on the cc->vmsd form. New targets should use dc->vmsd.
To avoid new targets to start using type (2), rename cc->vmsd as
cc->legacy_vmsd. The correct field to implement is dc->vmsd (the
DeviceClass one).
See also commit b170fce3dd0 ("cpu: Register VMStateDescription
through CPUState") for historic background.
[*] https://www.mail-archive.com/qemu-devel@nongnu.org/msg800849.html
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Cc: Peter Maydell <peter.maydell@linaro.org>
Message-Id: <20210517105140.1062037-13-f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Diffstat (limited to 'target/riscv/cpu.c')
-rw-r--r-- | target/riscv/cpu.c | 3 |
1 files changed, 1 insertions, 2 deletions
diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c index 3191fd0..16510da 100644 --- a/target/riscv/cpu.c +++ b/target/riscv/cpu.c @@ -638,8 +638,7 @@ static void riscv_cpu_class_init(ObjectClass *c, void *data) cc->disas_set_info = riscv_cpu_disas_set_info; #ifndef CONFIG_USER_ONLY cc->get_phys_page_debug = riscv_cpu_get_phys_page_debug; - /* For now, mark unmigratable: */ - cc->vmsd = &vmstate_riscv_cpu; + cc->legacy_vmsd = &vmstate_riscv_cpu; cc->write_elf64_note = riscv_cpu_write_elf64_note; cc->write_elf32_note = riscv_cpu_write_elf32_note; #endif |