[libvirt] [PATCH] libxl: add support for soft reset

The pvops Linux kernel implements machine_ops.crash_shutdown as static void xen_hvm_crash_shutdown(struct pt_regs *regs) { native_machine_crash_shutdown(regs); xen_reboot(SHUTDOWN_soft_reset); } but currently the libxl driver does not handle the soft reset shutdown event. As a result, the guest domain never proceeds past xen_reboot(), making it impossible for HVM domains to save a crash dump using kexec. This patch adds support for handling the soft reset event by calling libxl_domain_soft_reset() and re-enabling domain death events, which is similar to the xl tool handling of soft reset shutdown event. Signed-off-by: Jim Fehlig <jfehlig@suse.com> --- src/libxl/libxl_domain.c | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) diff --git a/src/libxl/libxl_domain.c b/src/libxl/libxl_domain.c index 0032b9dd11..295ec04a85 100644 --- a/src/libxl/libxl_domain.c +++ b/src/libxl/libxl_domain.c @@ -447,8 +447,10 @@ libxlDomainShutdownThread(void *opaque) virObjectEventPtr dom_event = NULL; libxl_shutdown_reason xl_reason = ev->u.domain_shutdown.shutdown_reason; libxlDriverConfigPtr cfg; + libxl_domain_config d_config; cfg = libxlDriverConfigGet(driver); + libxl_domain_config_init(&d_config); vm = virDomainObjListFindByID(driver->domains, ev->domid); if (!vm) { @@ -532,6 +534,33 @@ libxlDomainShutdownThread(void *opaque) * after calling libxl_domain_suspend() are handled by it's callers. */ goto endjob; + } else if (xl_reason == LIBXL_SHUTDOWN_REASON_SOFT_RESET) { + libxlDomainObjPrivatePtr priv = vm->privateData; + int res; + + if (libxl_retrieve_domain_configuration(cfg->ctx, vm->def->id, + &d_config) != 0) { + VIR_ERROR(_("Failed to retrieve config for VM '%s'. " + "Unable to perform soft reset. Destroying VM"), + vm->def->name); + goto destroy; + } + + if (priv->deathW) { + libxl_evdisable_domain_death(cfg->ctx, priv->deathW); + priv->deathW = NULL; + } + + res = libxl_domain_soft_reset(cfg->ctx, &d_config, vm->def->id, + NULL, NULL); + if (res != 0) { + VIR_ERROR(_("Failed to soft reset VM '%s'. Destroying VM"), + vm->def->name); + goto destroy; + } + libxl_evenable_domain_death(cfg->ctx, vm->def->id, 0, &priv->deathW); + libxl_domain_unpause(cfg->ctx, vm->def->id); + goto endjob; } else { VIR_INFO("Unhandled shutdown_reason %d", xl_reason); goto endjob; @@ -565,6 +594,7 @@ libxlDomainShutdownThread(void *opaque) virObjectEventStateQueue(driver->domainEventState, dom_event); libxl_event_free(cfg->ctx, ev); VIR_FREE(shutdown_info); + libxl_domain_config_dispose(&d_config); virObjectUnref(cfg); } -- 2.18.0

On 10/29/18 7:26 PM, Jim Fehlig wrote:
The pvops Linux kernel implements machine_ops.crash_shutdown as
static void xen_hvm_crash_shutdown(struct pt_regs *regs) { native_machine_crash_shutdown(regs); xen_reboot(SHUTDOWN_soft_reset); }
but currently the libxl driver does not handle the soft reset shutdown event. As a result, the guest domain never proceeds past xen_reboot(), making it impossible for HVM domains to save a crash dump using kexec.
This patch adds support for handling the soft reset event by calling libxl_domain_soft_reset() and re-enabling domain death events, which is similar to the xl tool handling of soft reset shutdown event.
Signed-off-by: Jim Fehlig <jfehlig@suse.com> --- src/libxl/libxl_domain.c | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+)
diff --git a/src/libxl/libxl_domain.c b/src/libxl/libxl_domain.c index 0032b9dd11..295ec04a85 100644 --- a/src/libxl/libxl_domain.c +++ b/src/libxl/libxl_domain.c @@ -447,8 +447,10 @@ libxlDomainShutdownThread(void *opaque) virObjectEventPtr dom_event = NULL; libxl_shutdown_reason xl_reason = ev->u.domain_shutdown.shutdown_reason; libxlDriverConfigPtr cfg; + libxl_domain_config d_config;
cfg = libxlDriverConfigGet(driver); + libxl_domain_config_init(&d_config);
vm = virDomainObjListFindByID(driver->domains, ev->domid); if (!vm) { @@ -532,6 +534,33 @@ libxlDomainShutdownThread(void *opaque) * after calling libxl_domain_suspend() are handled by it's callers. */ goto endjob; + } else if (xl_reason == LIBXL_SHUTDOWN_REASON_SOFT_RESET) { + libxlDomainObjPrivatePtr priv = vm->privateData; + int res;
I'm not sure why I have this useless local. I've squashed the below diff into my local branch. Regards, Jim diff --git a/src/libxl/libxl_domain.c b/src/libxl/libxl_domain.c index 295ec04a85..af5127bc2f 100644 --- a/src/libxl/libxl_domain.c +++ b/src/libxl/libxl_domain.c @@ -536,7 +536,6 @@ libxlDomainShutdownThread(void *opaque) goto endjob; } else if (xl_reason == LIBXL_SHUTDOWN_REASON_SOFT_RESET) { libxlDomainObjPrivatePtr priv = vm->privateData; - int res; if (libxl_retrieve_domain_configuration(cfg->ctx, vm->def->id, &d_config) != 0) { @@ -551,9 +550,8 @@ libxlDomainShutdownThread(void *opaque) priv->deathW = NULL; } - res = libxl_domain_soft_reset(cfg->ctx, &d_config, vm->def->id, - NULL, NULL); - if (res != 0) { + if (libxl_domain_soft_reset(cfg->ctx, &d_config, vm->def->id, + NULL, NULL) != 0) { VIR_ERROR(_("Failed to soft reset VM '%s'. Destroying VM"), vm->def->name); goto destroy;

On 10/30/2018 03:17 AM, Jim Fehlig wrote:
On 10/29/18 7:26 PM, Jim Fehlig wrote:
The pvops Linux kernel implements machine_ops.crash_shutdown as
static void xen_hvm_crash_shutdown(struct pt_regs *regs) { native_machine_crash_shutdown(regs); xen_reboot(SHUTDOWN_soft_reset); }
but currently the libxl driver does not handle the soft reset shutdown event. As a result, the guest domain never proceeds past xen_reboot(), making it impossible for HVM domains to save a crash dump using kexec.
This patch adds support for handling the soft reset event by calling libxl_domain_soft_reset() and re-enabling domain death events, which is similar to the xl tool handling of soft reset shutdown event.
Signed-off-by: Jim Fehlig <jfehlig@suse.com> --- src/libxl/libxl_domain.c | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+)
diff --git a/src/libxl/libxl_domain.c b/src/libxl/libxl_domain.c index 0032b9dd11..295ec04a85 100644 --- a/src/libxl/libxl_domain.c +++ b/src/libxl/libxl_domain.c @@ -447,8 +447,10 @@ libxlDomainShutdownThread(void *opaque) virObjectEventPtr dom_event = NULL; libxl_shutdown_reason xl_reason = ev->u.domain_shutdown.shutdown_reason; libxlDriverConfigPtr cfg; + libxl_domain_config d_config; cfg = libxlDriverConfigGet(driver); + libxl_domain_config_init(&d_config); vm = virDomainObjListFindByID(driver->domains, ev->domid); if (!vm) { @@ -532,6 +534,33 @@ libxlDomainShutdownThread(void *opaque) * after calling libxl_domain_suspend() are handled by it's callers. */ goto endjob; + } else if (xl_reason == LIBXL_SHUTDOWN_REASON_SOFT_RESET) { + libxlDomainObjPrivatePtr priv = vm->privateData; + int res;
I'm not sure why I have this useless local. I've squashed the below diff into my local branch.
ACK Michal

On 10/30/18 3:18 AM, Michal Privoznik wrote:
On 10/30/2018 03:17 AM, Jim Fehlig wrote:
On 10/29/18 7:26 PM, Jim Fehlig wrote:
The pvops Linux kernel implements machine_ops.crash_shutdown as
static void xen_hvm_crash_shutdown(struct pt_regs *regs) { native_machine_crash_shutdown(regs); xen_reboot(SHUTDOWN_soft_reset); }
but currently the libxl driver does not handle the soft reset shutdown event. As a result, the guest domain never proceeds past xen_reboot(), making it impossible for HVM domains to save a crash dump using kexec.
This patch adds support for handling the soft reset event by calling libxl_domain_soft_reset() and re-enabling domain death events, which is similar to the xl tool handling of soft reset shutdown event.
Signed-off-by: Jim Fehlig <jfehlig@suse.com> --- src/libxl/libxl_domain.c | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+)
diff --git a/src/libxl/libxl_domain.c b/src/libxl/libxl_domain.c index 0032b9dd11..295ec04a85 100644 --- a/src/libxl/libxl_domain.c +++ b/src/libxl/libxl_domain.c @@ -447,8 +447,10 @@ libxlDomainShutdownThread(void *opaque) virObjectEventPtr dom_event = NULL; libxl_shutdown_reason xl_reason = ev->u.domain_shutdown.shutdown_reason; libxlDriverConfigPtr cfg; + libxl_domain_config d_config; cfg = libxlDriverConfigGet(driver); + libxl_domain_config_init(&d_config); vm = virDomainObjListFindByID(driver->domains, ev->domid); if (!vm) { @@ -532,6 +534,33 @@ libxlDomainShutdownThread(void *opaque) * after calling libxl_domain_suspend() are handled by it's callers. */ goto endjob; + } else if (xl_reason == LIBXL_SHUTDOWN_REASON_SOFT_RESET) { + libxlDomainObjPrivatePtr priv = vm->privateData; + int res;
I'm not sure why I have this useless local. I've squashed the below diff into my local branch.
ACK
Thanks, but I found this didn't compile with Xen 4.6, our minimum supported Xen version. Soft reset was introduced in 4.7. I've sent a V2, which includes some cleanups to the libxlDomainShutdownThread function. Thanks for looking at it if you have time https://www.redhat.com/archives/libvir-list/2018-October/msg01370.html Regards, Jim
participants (2)
-
Jim Fehlig
-
Michal Privoznik