From 9b88cd7673dddf9336f50540e5735eb6f190200a Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?C=C3=A9dric=20Le=20Goater?= Date: Mon, 13 May 2019 10:42:36 +0200 Subject: [PATCH] spapr/xive: introduce a VM state change handler MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This handler is in charge of stabilizing the flow of event notifications in the XIVE controller before migrating a guest. This is a requirement before transferring the guest EQ pages to a destination. When the VM is stopped, the handler sets the source PQs to PENDING to stop the flow of events and to possibly catch a triggered interrupt occuring while the VM is stopped. Their previous state is saved. The XIVE controller is then synced through KVM to flush any in-flight event notification and to stabilize the EQs. At this stage, the EQ pages are marked dirty to make sure the EQ pages are transferred if a migration sequence is in progress. The previous configuration of the sources is restored when the VM resumes, after a migration or a stop. If an interrupt was queued while the VM was stopped, the handler simply generates the missing trigger. Signed-off-by: Cédric Le Goater Reviewed-by: David Gibson Message-Id: <20190513084245.25755-6-clg@kaod.org> Signed-off-by: David Gibson --- hw/intc/spapr_xive_kvm.c | 96 ++++++++++++++++++++++++++++++++++++- include/hw/ppc/spapr_xive.h | 1 + 2 files changed, 96 insertions(+), 1 deletion(-) diff --git a/hw/intc/spapr_xive_kvm.c b/hw/intc/spapr_xive_kvm.c index 8dd4f96e0b..735577a6f8 100644 --- a/hw/intc/spapr_xive_kvm.c +++ b/hw/intc/spapr_xive_kvm.c @@ -433,9 +433,100 @@ static void kvmppc_xive_get_queues(SpaprXive *xive, Error **errp) } } +/* + * The primary goal of the XIVE VM change handler is to mark the EQ + * pages dirty when all XIVE event notifications have stopped. + * + * Whenever the VM is stopped, the VM change handler sets the source + * PQs to PENDING to stop the flow of events and to possibly catch a + * triggered interrupt occuring while the VM is stopped. The previous + * state is saved in anticipation of a migration. The XIVE controller + * is then synced through KVM to flush any in-flight event + * notification and stabilize the EQs. + * + * At this stage, we can mark the EQ page dirty and let a migration + * sequence transfer the EQ pages to the destination, which is done + * just after the stop state. + * + * The previous configuration of the sources is restored when the VM + * runs again. If an interrupt was queued while the VM was stopped, + * simply generate a trigger. + */ +static void kvmppc_xive_change_state_handler(void *opaque, int running, + RunState state) +{ + SpaprXive *xive = opaque; + XiveSource *xsrc = &xive->source; + Error *local_err = NULL; + int i; + + /* + * Restore the sources to their initial state. This is called when + * the VM resumes after a stop or a migration. + */ + if (running) { + for (i = 0; i < xsrc->nr_irqs; i++) { + uint8_t pq = xive_source_esb_get(xsrc, i); + uint8_t old_pq; + + old_pq = xive_esb_read(xsrc, i, XIVE_ESB_SET_PQ_00 + (pq << 8)); + + /* + * An interrupt was queued while the VM was stopped, + * generate a trigger. + */ + if (pq == XIVE_ESB_RESET && old_pq == XIVE_ESB_QUEUED) { + xive_esb_trigger(xsrc, i); + } + } + + return; + } + + /* + * Mask the sources, to stop the flow of event notifications, and + * save the PQs locally in the XiveSource object. The XiveSource + * state will be collected later on by its vmstate handler if a + * migration is in progress. + */ + for (i = 0; i < xsrc->nr_irqs; i++) { + uint8_t pq = xive_esb_read(xsrc, i, XIVE_ESB_GET); + + /* + * PQ is set to PENDING to possibly catch a triggered + * interrupt occuring while the VM is stopped (hotplug event + * for instance) . + */ + if (pq != XIVE_ESB_OFF) { + pq = xive_esb_read(xsrc, i, XIVE_ESB_SET_PQ_10); + } + xive_source_esb_set(xsrc, i, pq); + } + + /* + * Sync the XIVE controller in KVM, to flush in-flight event + * notification that should be enqueued in the EQs and mark the + * XIVE EQ pages dirty to collect all updates. + */ + kvm_device_access(xive->fd, KVM_DEV_XIVE_GRP_CTRL, + KVM_DEV_XIVE_EQ_SYNC, NULL, true, &local_err); + if (local_err) { + error_report_err(local_err); + return; + } +} + void kvmppc_xive_synchronize_state(SpaprXive *xive, Error **errp) { - kvmppc_xive_source_get_state(&xive->source); + /* + * When the VM is stopped, the sources are masked and the previous + * state is saved in anticipation of a migration. We should not + * synchronize the source state in that case else we will override + * the saved state. + */ + if (runstate_is_running()) { + kvmppc_xive_source_get_state(&xive->source); + } /* EAT: there is no extra state to query from KVM */ @@ -515,6 +606,9 @@ void kvmppc_xive_connect(SpaprXive *xive, Error **errp) "xive.tima", tima_len, xive->tm_mmap); sysbus_init_mmio(SYS_BUS_DEVICE(xive), &xive->tm_mmio); + xive->change = qemu_add_vm_change_state_handler( + kvmppc_xive_change_state_handler, xive); + kvm_kernel_irqchip = true; kvm_msi_via_irqfd_allowed = true; kvm_gsi_direct_mapping = true; diff --git a/include/hw/ppc/spapr_xive.h b/include/hw/ppc/spapr_xive.h index 7e49badd8c..734662c12a 100644 --- a/include/hw/ppc/spapr_xive.h +++ b/include/hw/ppc/spapr_xive.h @@ -42,6 +42,7 @@ typedef struct SpaprXive { /* KVM support */ int fd; void *tm_mmap; + VMChangeStateEntry *change; } SpaprXive; /*