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envelope-from=farosas@suse.de; helo=smtp-out1.suse.de X-Spam_score_int: -43 X-Spam_score: -4.4 X-Spam_bar: ---- X-Spam_report: (-4.4 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_MED=-2.3, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 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 Peter Xu writes: > On Tue, Apr 30, 2024 at 11:00:24AM -0300, Fabiano Rosas wrote: >> Philippe Mathieu-Daud=C3=A9 writes: >>=20 >> > (Cc'ing migration maintainers) >> > >> > On 30/4/24 03:23, Song Gao wrote: >> >> vmstate does not save kvm_state_conter, >> >> which can cause VM recovery from disk to fail. >> > >> > Cc: qemu-stable@nongnu.org >> > Fixes: d11681c94f ("target/loongarch: Implement kvm_arch_init_vcpu") >> > >> >> Signed-off-by: Song Gao >> >> --- >> >> target/loongarch/machine.c | 2 ++ >> >> 1 file changed, 2 insertions(+) >> >>=20 >> >> diff --git a/target/loongarch/machine.c b/target/loongarch/machine.c >> >> index c7029fb9b4..4cd1bf06ff 100644 >> >> --- a/target/loongarch/machine.c >> >> +++ b/target/loongarch/machine.c >> >> @@ -191,6 +191,8 @@ const VMStateDescription vmstate_loongarch_cpu = =3D { >> >> VMSTATE_STRUCT_ARRAY(env.tlb, LoongArchCPU, LOONGARCH_TLB_M= AX, >> >> 0, vmstate_tlb, LoongArchTLB), >> >>=20=20=20 >> >> + VMSTATE_UINT64(kvm_state_counter, LoongArchCPU), >> >> + >> >> VMSTATE_END_OF_LIST() >> >> }, >> >> .subsections =3D (const VMStateDescription * const []) { >> > >> > The migration stream is versioned, so you should increase it, >> > but this field is only relevant for KVM (it shouldn't be there >> > in non-KVM builds). IMHO the correct migration way to fix that >> > is (untested): >> > >> > -- >8 -- >> > diff --git a/target/loongarch/machine.c b/target/loongarch/machine.c >> > index c7029fb9b4..08032c6d71 100644 >> > --- a/target/loongarch/machine.c >> > +++ b/target/loongarch/machine.c >> > @@ -8,8 +8,27 @@ >> > #include "qemu/osdep.h" >> > #include "cpu.h" >> > #include "migration/cpu.h" >> > +#include "sysemu/kvm.h" >> > #include "vec.h" >> > >> > +#ifdef CONFIG_KVM >> > +static bool kvmcpu_needed(void *opaque) >> > +{ >> > + return kvm_enabled(); >> > +} >> > + >> > +static const VMStateDescription vmstate_kvmtimer =3D { >> > + .name =3D "cpu/kvmtimer", >> > + .version_id =3D 1, >> > + .minimum_version_id =3D 1, >> > + .needed =3D kvmcpu_needed, >> > + .fields =3D (const VMStateField[]) { >> > + VMSTATE_UINT64(kvm_state_counter, LoongArchCPU), >> > + VMSTATE_END_OF_LIST() >> > + } >> > +}; >> > +#endif /* CONFIG_KVM */ >> > + >> > static const VMStateDescription vmstate_fpu_reg =3D { >> > .name =3D "fpu_reg", >> > .version_id =3D 1, >> > @@ -194,6 +213,9 @@ const VMStateDescription vmstate_loongarch_cpu =3D= { >> > VMSTATE_END_OF_LIST() >> > }, >> > .subsections =3D (const VMStateDescription * const []) { >> > +#ifdef CONFIG_KVM >> > + &vmstate_kvmcpu, >> > +#endif >> > &vmstate_fpu, >> > &vmstate_lsx, >> > &vmstate_lasx, >> > --- >>=20 >> LGTM, I'd just leave only the .needed function under CONFIG_KVM instead >> of the whole subsection. > > But when !KVM it means there's no ".needed" and it'll still be migrated? I expressed myself poorly, I meant put the return from .needed under CONFIG_KVM. But that is not even necessary, kvm_enabled() is enough. > > IMHO it depends on whether loongarch is in the state already of trying to > keep its ABI at all. I think we should still try to enjoy the time when > that ABI is not required, then we can simply add whatever fields, and let > things break with no big deal. > > Note that if with CONFIG_KVM it means it can break migration between kvm > v.s. tcg when only one qemu enabled kvm when compile. Considering the > patch is from the maintainer (which seems to say "breaking that is all > fine!") I'd say the original patch looks good actually, as it allows kvm / > tcg migrations too as a baseline. I'm fine with this approach as well. > > Thanks,