| Message ID | 20230105155019.72200-3-imbrenda@linux.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | s390x/pv: Add support for asynchronous teardown for reboot | expand |
On 05/01/2023 16.50, Claudio Imbrenda wrote: > This patch adds support for the asynchronous teardown for reboot for > protected VMs. > > When attempting to tear down a protected VM, try to use the new > asynchronous interface first. If that fails, fall back to the classic > synchronous one. > > The asynchronous interface involves invoking the new > KVM_PV_ASYNC_DISABLE_PREPARE command for the KVM_S390_PV_COMMAND ioctl. > > This will prepare the current protected VM for asynchronous teardown. > Once the protected VM is prepared for teardown, execution can continue > immediately. > > Once the protected VM has been prepared, a new thread is started to > actually perform the teardown. The new thread uses the new > KVM_PV_ASYNC_DISABLE command for the KVM_S390_PV_COMMAND ioctl. The > previously prepared protected VM is torn down in the new thread. > > Once KVM_PV_ASYNC_DISABLE is invoked, it is possible to use > KVM_PV_ASYNC_DISABLE_PREPARE again. If a protected VM has already been > prepared and its cleanup has not started, it will not be possible to > prepare a new VM. In that case the classic synchronous teardown has to > be performed. > > The synchronous teardown will now also clean up any prepared VMs whose > asynchronous teardown has not been initiated yet. > > This considerably speeds up the reboot of a protected VM; for large VMs > especially, it could take a long time to perform a reboot with the > traditional synchronous teardown, while with this patch it is almost > immediate. > > Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com> > --- > hw/s390x/pv.c | 25 +++++++++++++++++++++++++ > hw/s390x/s390-virtio-ccw.c | 5 ++++- > include/hw/s390x/pv.h | 2 ++ > 3 files changed, 31 insertions(+), 1 deletion(-) > > diff --git a/hw/s390x/pv.c b/hw/s390x/pv.c > index 8dfe92d8df..3d1c529eb5 100644 > --- a/hw/s390x/pv.c > +++ b/hw/s390x/pv.c > @@ -16,6 +16,7 @@ > #include "qapi/error.h" > #include "qemu/error-report.h" > #include "sysemu/kvm.h" > +#include "sysemu/cpus.h" > #include "qom/object_interfaces.h" > #include "exec/confidential-guest-support.h" > #include "hw/s390x/ipl.h" > @@ -107,6 +108,30 @@ void s390_pv_vm_disable(void) > s390_pv_cmd_exit(KVM_PV_DISABLE, NULL); > } > > +static void *s390_pv_do_unprot_async_fn(void *p) > +{ > + s390_pv_cmd_exit(KVM_PV_ASYNC_CLEANUP_PERFORM, NULL); > + return NULL; > +} > + > +bool s390_pv_vm_try_disable_async(void) > +{ > + QemuThread *t; > + > + if (!kvm_check_extension(kvm_state, KVM_CAP_S390_PROTECTED_ASYNC_DISABLE)) { > + return false; > + } > + if (s390_pv_cmd(KVM_PV_ASYNC_CLEANUP_PREPARE, NULL) != 0) { > + return false; > + } > + > + t = g_malloc0(sizeof(QemuThread)); Sorry for not noticing it in v1 already ... but isn't this leaking memory? Who's supposed to free "t" again? Thomas > + qemu_thread_create(t, "async_cleanup", s390_pv_do_unprot_async_fn, NULL, > + QEMU_THREAD_DETACHED); > + > + return true; > +}
On Tue, 17 Jan 2023 09:53:46 +0100 Thomas Huth <thuth@redhat.com> wrote: [...] > > +static void *s390_pv_do_unprot_async_fn(void *p) > > +{ > > + s390_pv_cmd_exit(KVM_PV_ASYNC_CLEANUP_PERFORM, NULL); > > + return NULL; > > +} > > + > > +bool s390_pv_vm_try_disable_async(void) > > +{ > > + QemuThread *t; > > + > > + if (!kvm_check_extension(kvm_state, KVM_CAP_S390_PROTECTED_ASYNC_DISABLE)) { > > + return false; > > + } > > + if (s390_pv_cmd(KVM_PV_ASYNC_CLEANUP_PREPARE, NULL) != 0) { > > + return false; > > + } > > + > > + t = g_malloc0(sizeof(QemuThread)); > > Sorry for not noticing it in v1 already ... but isn't this leaking memory? > Who's supposed to free "t" again? I assumed that QEMU_THREAD_DETACHED took care of that; it seems like I was mistaken (oops). I'll find a way to fix this > > Thomas > > > > + qemu_thread_create(t, "async_cleanup", s390_pv_do_unprot_async_fn, NULL, > > + QEMU_THREAD_DETACHED); > > + > > + return true; > > +} >
diff --git a/hw/s390x/pv.c b/hw/s390x/pv.c index 8dfe92d8df..3d1c529eb5 100644 --- a/hw/s390x/pv.c +++ b/hw/s390x/pv.c @@ -16,6 +16,7 @@ #include "qapi/error.h" #include "qemu/error-report.h" #include "sysemu/kvm.h" +#include "sysemu/cpus.h" #include "qom/object_interfaces.h" #include "exec/confidential-guest-support.h" #include "hw/s390x/ipl.h" @@ -107,6 +108,30 @@ void s390_pv_vm_disable(void) s390_pv_cmd_exit(KVM_PV_DISABLE, NULL); } +static void *s390_pv_do_unprot_async_fn(void *p) +{ + s390_pv_cmd_exit(KVM_PV_ASYNC_CLEANUP_PERFORM, NULL); + return NULL; +} + +bool s390_pv_vm_try_disable_async(void) +{ + QemuThread *t; + + if (!kvm_check_extension(kvm_state, KVM_CAP_S390_PROTECTED_ASYNC_DISABLE)) { + return false; + } + if (s390_pv_cmd(KVM_PV_ASYNC_CLEANUP_PREPARE, NULL) != 0) { + return false; + } + + t = g_malloc0(sizeof(QemuThread)); + qemu_thread_create(t, "async_cleanup", s390_pv_do_unprot_async_fn, NULL, + QEMU_THREAD_DETACHED); + + return true; +} + int s390_pv_set_sec_parms(uint64_t origin, uint64_t length) { struct kvm_s390_pv_sec_parm args = { diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c index f22f61b8b6..503f212a31 100644 --- a/hw/s390x/s390-virtio-ccw.c +++ b/hw/s390x/s390-virtio-ccw.c @@ -41,6 +41,7 @@ #include "hw/qdev-properties.h" #include "hw/s390x/tod.h" #include "sysemu/sysemu.h" +#include "sysemu/cpus.h" #include "hw/s390x/pv.h" #include "migration/blocker.h" #include "qapi/visitor.h" @@ -329,7 +330,9 @@ static inline void s390_do_cpu_ipl(CPUState *cs, run_on_cpu_data arg) static void s390_machine_unprotect(S390CcwMachineState *ms) { - s390_pv_vm_disable(); + if (!s390_pv_vm_try_disable_async()) { + s390_pv_vm_disable(); + } ms->pv = false; migrate_del_blocker(pv_mig_blocker); error_free_or_abort(&pv_mig_blocker); diff --git a/include/hw/s390x/pv.h b/include/hw/s390x/pv.h index 9360aa1091..966306a9db 100644 --- a/include/hw/s390x/pv.h +++ b/include/hw/s390x/pv.h @@ -41,6 +41,7 @@ static inline bool s390_is_pv(void) int s390_pv_query_info(void); int s390_pv_vm_enable(void); void s390_pv_vm_disable(void); +bool s390_pv_vm_try_disable_async(void); int s390_pv_set_sec_parms(uint64_t origin, uint64_t length); int s390_pv_unpack(uint64_t addr, uint64_t size, uint64_t tweak); void s390_pv_prep_reset(void); @@ -60,6 +61,7 @@ static inline bool s390_is_pv(void) { return false; } static inline int s390_pv_query_info(void) { return 0; } static inline int s390_pv_vm_enable(void) { return 0; } static inline void s390_pv_vm_disable(void) {} +static inline bool s390_pv_vm_try_disable_async(void) { return false; } static inline int s390_pv_set_sec_parms(uint64_t origin, uint64_t length) { return 0; } static inline int s390_pv_unpack(uint64_t addr, uint64_t size, uint64_t tweak) { return 0; } static inline void s390_pv_prep_reset(void) {}
This patch adds support for the asynchronous teardown for reboot for protected VMs. When attempting to tear down a protected VM, try to use the new asynchronous interface first. If that fails, fall back to the classic synchronous one. The asynchronous interface involves invoking the new KVM_PV_ASYNC_DISABLE_PREPARE command for the KVM_S390_PV_COMMAND ioctl. This will prepare the current protected VM for asynchronous teardown. Once the protected VM is prepared for teardown, execution can continue immediately. Once the protected VM has been prepared, a new thread is started to actually perform the teardown. The new thread uses the new KVM_PV_ASYNC_DISABLE command for the KVM_S390_PV_COMMAND ioctl. The previously prepared protected VM is torn down in the new thread. Once KVM_PV_ASYNC_DISABLE is invoked, it is possible to use KVM_PV_ASYNC_DISABLE_PREPARE again. If a protected VM has already been prepared and its cleanup has not started, it will not be possible to prepare a new VM. In that case the classic synchronous teardown has to be performed. The synchronous teardown will now also clean up any prepared VMs whose asynchronous teardown has not been initiated yet. This considerably speeds up the reboot of a protected VM; for large VMs especially, it could take a long time to perform a reboot with the traditional synchronous teardown, while with this patch it is almost immediate. Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com> --- hw/s390x/pv.c | 25 +++++++++++++++++++++++++ hw/s390x/s390-virtio-ccw.c | 5 ++++- include/hw/s390x/pv.h | 2 ++ 3 files changed, 31 insertions(+), 1 deletion(-)