On 2021-08-06 14:43, Steve Sistare wrote: > Preserve vfio INTX state across cpr restart. Preserve VFIOINTx fields as > follows: > pin : Recover this from the vfio config in kernel space > interrupt : Preserve its eventfd descriptor across exec. > unmask : Ditto > route.irq : This could perhaps be recovered in vfio_pci_post_load by > calling pci_device_route_intx_to_irq(pin), whose implementation reads > config space for a bridge device such as ich9. However, there is no > guarantee that the bridge vmstate is read before vfio vmstate. Rather > than fiddling with MigrationPriority for vmstate handlers, explicitly > save route.irq in vfio vmstate. > pending : save in vfio vmstate. > mmap_timeout, mmap_timer : Re-initialize > bool kvm_accel : Re-initialize > > In vfio_realize, defer calling vfio_intx_enable until the vmstate > is available, in vfio_pci_post_load. Modify vfio_intx_enable and > vfio_intx_kvm_enable to skip vfio initialization, but still perform > kvm initialization. > > Signed-off-by: Steve Sistare <steven.sist...@oracle.com>
Hi Steve, Not directly related to this patch, but since the context is close: it looks like this series only takes care of exec restart mode of vfio-pci, have you had any thoughts on kexec reboot mode with vfio-pci? The general idea is if DMAR context is not lost during kexec, we should be able to set up irqfds again and things will just work? Fam -- PS some more info below: I have some local kernel patches to kexec reboot most part of the host kernel while keeping IOMMU DMAR tables in a valid state; with that, not many extra things are needed in addition to restore it. A PoC is like below (I can share more details of the kernel changes if this patch makes any sense): commit f8951e58be86bd6e37f816394a9a73f28d8059fc Author: Fam Zheng <fam.zh...@bytedance.com> Date: Mon Mar 21 13:19:49 2022 +0000 cpr: Add live-update support to vfio-pci devices In cpr-save, always serialize the vfio-pci states. In cpr-load, add a '-restore' mode that will do VFIO_GROUP_GET_DEVICE_FD_INTACT and skip DMAR setup, somewhat similar to the current cpr exec mode. Signed-off-by: Fam Zheng <fam.zh...@bytedance.com> diff --git a/hw/pci/msix.c b/hw/pci/msix.c index 73f4259556..e36f0ef97d 100644 --- a/hw/pci/msix.c +++ b/hw/pci/msix.c @@ -584,10 +584,15 @@ void msix_init_vector_notifiers(PCIDevice *dev, MSIVectorReleaseNotifier release_notifier, MSIVectorPollNotifier poll_notifier) { + int vector; + assert(use_notifier && release_notifier); dev->msix_vector_use_notifier = use_notifier; dev->msix_vector_release_notifier = release_notifier; dev->msix_vector_poll_notifier = poll_notifier; + for (vector = 0; vector < dev->msix_entries_nr; ++vector) { + msix_handle_mask_update(dev, vector, true); + } } int msix_set_vector_notifiers(PCIDevice *dev, diff --git a/hw/vfio/common.c b/hw/vfio/common.c index 605ffbb5d0..f1240410a8 100644 --- a/hw/vfio/common.c +++ b/hw/vfio/common.c @@ -2066,6 +2066,9 @@ static int vfio_connect_container(VFIOGroup *group, AddressSpace *as, bool reused; VFIOAddressSpace *space; + if (restore) { + return 0; + } space = vfio_get_address_space(as); fd = cpr_find_fd("vfio_container_for_group", group->groupid); reused = (fd > 0); @@ -2486,7 +2489,8 @@ int vfio_get_device(VFIOGroup *group, const char *name, fd = cpr_find_fd(name, 0); reused = (fd >= 0); if (!reused) { - fd = ioctl(group->fd, VFIO_GROUP_GET_DEVICE_FD, name); + int op = restore ? VFIO_GROUP_GET_DEVICE_FD_INTACT : VFIO_GROUP_GET_DEVICE_FD; + fd = ioctl(group->fd, op, name); } if (fd < 0) { diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c index e32513c668..9da5f93228 100644 --- a/hw/vfio/pci.c +++ b/hw/vfio/pci.c @@ -361,7 +361,7 @@ static int vfio_intx_enable(VFIOPCIDevice *vdev, Error **errp) * Do not alter interrupt state during vfio_realize and cpr-load. The * reused flag is cleared thereafter. */ - if (!vdev->pdev.reused) { + if (!vdev->pdev.reused && !restore) { vfio_disable_interrupts(vdev); } @@ -388,7 +388,7 @@ static int vfio_intx_enable(VFIOPCIDevice *vdev, Error **errp) fd = event_notifier_get_fd(&vdev->intx.interrupt); qemu_set_fd_handler(fd, vfio_intx_interrupt, NULL, vdev); - if (vdev->pdev.reused) { + if (vdev->pdev.reused && !restore) { vfio_intx_reenable_kvm(vdev, &err); goto finish; } @@ -2326,6 +2326,9 @@ static int vfio_pci_hot_reset(VFIOPCIDevice *vdev, bool single) int ret, i, count; bool multi = false; + if (restore) { + return 0; + } trace_vfio_pci_hot_reset(vdev->vbasedev.name, single ? "one" : "multi"); if (!single) { @@ -3185,7 +3188,7 @@ static void vfio_realize(PCIDevice *pdev, Error **errp) kvm_irqchip_add_change_notifier(&vdev->irqchip_change_notifier); /* Wait until cpr-load reads intx routing data to enable */ - if (!pdev->reused) { + if (!pdev->reused && !restore) { ret = vfio_intx_enable(vdev, errp); if (ret) { goto out_deregister; @@ -3295,7 +3298,7 @@ static void vfio_pci_reset(DeviceState *dev) VFIOPCIDevice *vdev = VFIO_PCI(dev); /* Do not reset the device during qemu_system_reset prior to cpr-load */ - if (vdev->pdev.reused) { + if (vdev->pdev.reused || restore) { return; } @@ -3429,33 +3432,40 @@ static void vfio_merge_config(VFIOPCIDevice *vdev) static void vfio_claim_vectors(VFIOPCIDevice *vdev, int nr_vectors, bool msix) { - int i, fd; + int i, fd, ret; bool pending = false; PCIDevice *pdev = &vdev->pdev; + pdev->msix_entries_nr = nr_vectors; vdev->nr_vectors = nr_vectors; vdev->msi_vectors = g_new0(VFIOMSIVector, nr_vectors); vdev->interrupt = msix ? VFIO_INT_MSIX : VFIO_INT_MSI; - for (i = 0; i < nr_vectors; i++) { - VFIOMSIVector *vector = &vdev->msi_vectors[i]; - - fd = load_event_fd(vdev, "interrupt", i); - if (fd >= 0) { - vfio_vector_init(vdev, i); - qemu_set_fd_handler(fd, vfio_msi_interrupt, NULL, vector); + if (restore) { + ret = vfio_enable_vectors(vdev, true); + if (ret) { + error_report("vfio: failed to enable vectors, %d", ret); } + } else { + for (i = 0; i < nr_vectors; i++) { + VFIOMSIVector *vector = &vdev->msi_vectors[i]; - if (load_event_fd(vdev, "kvm_interrupt", i) >= 0) { - vfio_add_kvm_msi_virq(vdev, vector, i, msix); - } + fd = load_event_fd(vdev, "interrupt", i); + if (fd >= 0) { + vfio_vector_init(vdev, i); + qemu_set_fd_handler(fd, vfio_msi_interrupt, NULL, vector); + } - if (msix && msix_is_pending(pdev, i) && msix_is_masked(pdev, i)) { - set_bit(i, vdev->msix->pending); - pending = true; + if (load_event_fd(vdev, "kvm_interrupt", i) >= 0) { + vfio_add_kvm_msi_virq(vdev, vector, i, msix); + } + + if (msix && msix_is_pending(pdev, i) && msix_is_masked(pdev, i)) { + set_bit(i, vdev->msix->pending); + pending = true; + } } } - if (msix) { memory_region_set_enabled(&pdev->msix_pba_mmio, pending); } @@ -3534,7 +3544,7 @@ static const VMStateDescription vfio_intx_vmstate = { static bool vfio_pci_needed(void *opaque) { - return cpr_get_mode() == CPR_MODE_RESTART; + return 1; } static const VMStateDescription vfio_pci_vmstate = { diff --git a/include/sysemu/sysemu.h b/include/sysemu/sysemu.h index 6241c20fb1..0179b0aa90 100644 --- a/include/sysemu/sysemu.h +++ b/include/sysemu/sysemu.h @@ -26,6 +26,7 @@ void configure_rtc(QemuOpts *opts); void qemu_init_subsystems(void); extern int autostart; +extern int restore; typedef enum { VGA_NONE, VGA_STD, VGA_CIRRUS, VGA_VMWARE, VGA_XENFB, VGA_QXL, diff --git a/linux-headers/linux/vfio.h b/linux-headers/linux/vfio.h index e680594f27..65c3bab074 100644 --- a/linux-headers/linux/vfio.h +++ b/linux-headers/linux/vfio.h @@ -188,6 +188,8 @@ struct vfio_group_status { */ #define VFIO_GROUP_GET_DEVICE_FD _IO(VFIO_TYPE, VFIO_BASE + 6) +#define VFIO_GROUP_GET_DEVICE_FD_INTACT _IO(VFIO_TYPE, VFIO_BASE + 21) + /* --------------- IOCTLs for DEVICE file descriptors --------------- */ /** diff --git a/qemu-options.hx b/qemu-options.hx index 8b90d04cb9..03666a59b3 100644 --- a/qemu-options.hx +++ b/qemu-options.hx @@ -3984,6 +3984,10 @@ SRST option is experimental. ERST +DEF("restore", 0, QEMU_OPTION_restore, \ + "-restore restore mode", + QEMU_ARCH_ALL) + DEF("S", 0, QEMU_OPTION_S, \ "-S freeze CPU at startup (use 'c' to start execution)\n", QEMU_ARCH_ALL) diff --git a/softmmu/globals.c b/softmmu/globals.c index a18fd8dcf3..6fcb5846b4 100644 --- a/softmmu/globals.c +++ b/softmmu/globals.c @@ -41,6 +41,7 @@ bool enable_cpu_pm; int nb_nics; NICInfo nd_table[MAX_NICS]; int autostart = 1; +int restore; int vga_interface_type = VGA_NONE; Chardev *parallel_hds[MAX_PARALLEL_PORTS]; int win2k_install_hack; diff --git a/softmmu/vl.c b/softmmu/vl.c index f14e29e622..fba6b577cb 100644 --- a/softmmu/vl.c +++ b/softmmu/vl.c @@ -3088,6 +3088,9 @@ void qemu_init(int argc, char **argv, char **envp) case QEMU_OPTION_S: autostart = 0; break; + case QEMU_OPTION_restore: + restore = 1; + break; case QEMU_OPTION_k: keyboard_layout = optarg; break;