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Re: [RFC PATCH] pcie: Defer hot unplug until migration is complete
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From: |
Julia Suvorova |
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Subject: |
Re: [RFC PATCH] pcie: Defer hot unplug until migration is complete |
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Date: |
Mon, 27 Jan 2020 16:12:59 +0100 |
On Fri, Jan 17, 2020 at 5:56 PM Dr. David Alan Gilbert
<address@hidden> wrote:
>
> * Julia Suvorova (address@hidden) wrote:
> > On Mon, Jan 13, 2020 at 3:04 PM Yury Kotov <address@hidden> wrote:
> > >
> > > Devices hot-plug during migration is not allowed and disabled in
> > > corresponding QMP-commands (device_add, device_del).
> > > But guest still can unplug device by powering it off
> > > (Example: echo 0 > /sys/bus/pci/slots/XXX/power).
> >
> > You don't want to unplug device due to powering the slot off in the
> > first place. Instead, you can hide the device (see f3a8505656), and
> > make it visible again when the slot is powered on. Thus, the guest
> > will not be able to unplug the device and your problem will disappear.
> >
> > Best regards, Julia Suvorova.
>
> I don't really understand how hidden a hidden device is;
> will it still get it's migration data migrated?
> - if so what state is it in? What gets migrated?
> is the behaviour after reset/reboot consistent with what we want
> in the existing unplug behaviour?
> Say it's a disk device; will it release the lock on the disk backend?
>
> It feels like the semantics need to be tied down a bit.
Yes. the concept is still raw, and patches presented don't provide
functionality we need. I'm working on it now.
Best regards, Julia Suvorova.
> > > Fix it by deferring unplugging until the migration is complete.
> > >
> > > Signed-off-by: Yury Kotov <address@hidden>
> > > ---
> > > hw/pci-bridge/gen_pcie_root_port.c | 7 ++++
> > > hw/pci-bridge/ioh3420.c | 7 ++++
> > > hw/pci-bridge/xio3130_downstream.c | 7 ++++
> > > hw/pci/pcie.c | 54 +++++++++++++++++++++++-------
> > > hw/pci/pcie_port.c | 47 ++++++++++++++++++++++++++
> > > include/hw/pci/pcie.h | 1 +
> > > include/hw/pci/pcie_port.h | 20 +++++++++++
> > > 7 files changed, 130 insertions(+), 13 deletions(-)
> > >
> > > diff --git a/hw/pci-bridge/gen_pcie_root_port.c
> > > b/hw/pci-bridge/gen_pcie_root_port.c
> > > index 9eaefebca8..5b3c202341 100644
> > > --- a/hw/pci-bridge/gen_pcie_root_port.c
> > > +++ b/hw/pci-bridge/gen_pcie_root_port.c
> > > @@ -100,6 +100,9 @@ static void gen_rp_realize(DeviceState *dev, Error
> > > **errp)
> > > }
> > > }
> > >
> > > +static const VMStateDescription vmstate_rp_deffered_unplug =
> > > + VMSTATE_DEFFERED_UNPLUG("pcie-root-port");
> > > +
> > > static const VMStateDescription vmstate_rp_dev = {
> > > .name = "pcie-root-port",
> > > .priority = MIG_PRI_PCI_BUS,
> > > @@ -114,6 +117,10 @@ static const VMStateDescription vmstate_rp_dev = {
> > > GenPCIERootPort,
> > > gen_rp_test_migrate_msix),
> > > VMSTATE_END_OF_LIST()
> > > + },
> > > + .subsections = (const VMStateDescription * []) {
> > > + &vmstate_rp_deffered_unplug,
> > > + NULL
> > > }
> > > };
> > >
> > > diff --git a/hw/pci-bridge/ioh3420.c b/hw/pci-bridge/ioh3420.c
> > > index f1e16135a3..2399a9a87f 100644
> > > --- a/hw/pci-bridge/ioh3420.c
> > > +++ b/hw/pci-bridge/ioh3420.c
> > > @@ -82,6 +82,9 @@ static void ioh3420_interrupts_uninit(PCIDevice *d)
> > > msi_uninit(d);
> > > }
> > >
> > > +static const VMStateDescription vmstate_ioh3420_deffered_unplug =
> > > + VMSTATE_DEFFERED_UNPLUG("ioh-3240-express-root-port");
> > > +
> > > static const VMStateDescription vmstate_ioh3420 = {
> > > .name = "ioh-3240-express-root-port",
> > > .priority = MIG_PRI_PCI_BUS,
> > > @@ -93,6 +96,10 @@ static const VMStateDescription vmstate_ioh3420 = {
> > > VMSTATE_STRUCT(parent_obj.parent_obj.parent_obj.exp.aer_log,
> > > PCIESlot, 0, vmstate_pcie_aer_log, PCIEAERLog),
> > > VMSTATE_END_OF_LIST()
> > > + },
> > > + .subsections = (const VMStateDescription * []) {
> > > + &vmstate_ioh3420_deffered_unplug,
> > > + NULL
> > > }
> > > };
> > >
> > > diff --git a/hw/pci-bridge/xio3130_downstream.c
> > > b/hw/pci-bridge/xio3130_downstream.c
> > > index a9f084b863..a5b4fe08ee 100644
> > > --- a/hw/pci-bridge/xio3130_downstream.c
> > > +++ b/hw/pci-bridge/xio3130_downstream.c
> > > @@ -139,6 +139,9 @@ static Property xio3130_downstream_props[] = {
> > > DEFINE_PROP_END_OF_LIST()
> > > };
> > >
> > > +static const VMStateDescription
> > > vmstate_xio3130_downstream_deffered_unplug =
> > > + VMSTATE_DEFFERED_UNPLUG("xio3130-express-downstream-port");
> > > +
> > > static const VMStateDescription vmstate_xio3130_downstream = {
> > > .name = "xio3130-express-downstream-port",
> > > .priority = MIG_PRI_PCI_BUS,
> > > @@ -150,6 +153,10 @@ static const VMStateDescription
> > > vmstate_xio3130_downstream = {
> > > VMSTATE_STRUCT(parent_obj.parent_obj.parent_obj.exp.aer_log,
> > > PCIESlot, 0, vmstate_pcie_aer_log, PCIEAERLog),
> > > VMSTATE_END_OF_LIST()
> > > + },
> > > + .subsections = (const VMStateDescription * []) {
> > > + &vmstate_xio3130_downstream_deffered_unplug,
> > > + NULL
> > > }
> > > };
> > >
> > > diff --git a/hw/pci/pcie.c b/hw/pci/pcie.c
> > > index 08718188bb..29f0e5c05b 100644
> > > --- a/hw/pci/pcie.c
> > > +++ b/hw/pci/pcie.c
> > > @@ -28,6 +28,8 @@
> > > #include "hw/pci/pcie_regs.h"
> > > #include "hw/pci/pcie_port.h"
> > > #include "qemu/range.h"
> > > +#include "sysemu/sysemu.h"
> > > +#include "migration/misc.h"
> > >
> > > //#define DEBUG_PCIE
> > > #ifdef DEBUG_PCIE
> > > @@ -575,6 +577,7 @@ void pcie_cap_slot_reset(PCIDevice *dev)
> > >
> > > if (dev->cap_present & QEMU_PCIE_SLTCAP_PCP) {
> > > /* Downstream ports enforce device number 0. */
> > > + PCIESlot *slot = PCIE_SLOT(dev);
> > > bool populated =
> > > pci_bridge_get_sec_bus(PCI_BRIDGE(dev))->devices[0];
> > > uint16_t pic;
> > >
> > > @@ -588,6 +591,7 @@ void pcie_cap_slot_reset(PCIDevice *dev)
> > >
> > > pic = populated ? PCI_EXP_SLTCTL_PIC_ON : PCI_EXP_SLTCTL_PIC_OFF;
> > > pci_word_test_and_set_mask(exp_cap + PCI_EXP_SLTCTL, pic);
> > > + slot->unplug_is_deferred = false;
> > > }
> > >
> > > pci_word_test_and_clear_mask(exp_cap + PCI_EXP_SLTSTA,
> > > @@ -608,13 +612,42 @@ void pcie_cap_slot_get(PCIDevice *dev, uint16_t
> > > *slt_ctl, uint16_t *slt_sta)
> > > *slt_sta = pci_get_word(exp_cap + PCI_EXP_SLTSTA);
> > > }
> > >
> > > +static void pcie_cap_slot_unplug(PCIDevice *dev)
> > > +{
> > > + uint32_t pos = dev->exp.exp_cap;
> > > + uint8_t *exp_cap = dev->config + pos;
> > > + PCIBus *sec_bus = pci_bridge_get_sec_bus(PCI_BRIDGE(dev));
> > > +
> > > + pci_for_each_device(sec_bus, pci_bus_num(sec_bus),
> > > + pcie_unplug_device, NULL);
> > > + pci_word_test_and_clear_mask(exp_cap + PCI_EXP_SLTSTA,
> > > PCI_EXP_SLTSTA_PDS);
> > > + if (dev->cap_present & QEMU_PCIE_LNKSTA_DLLLA) {
> > > + pci_word_test_and_clear_mask(exp_cap + PCI_EXP_LNKSTA,
> > > + PCI_EXP_LNKSTA_DLLLA);
> > > + }
> > > + pci_word_test_and_set_mask(exp_cap + PCI_EXP_SLTSTA,
> > > PCI_EXP_SLTSTA_PDC);
> > > + hotplug_event_notify(dev);
> > > +}
> > > +
> > > +void pcie_cap_slot_deferred_unplug(PCIDevice *dev)
> > > +{
> > > + PCIESlot *slot = PCIE_SLOT(dev);
> > > +
> > > + if (migration_is_idle() && slot->unplug_is_deferred) {
> > > + pcie_cap_slot_unplug(dev);
> > > + slot->unplug_is_deferred = false;
> > > + }
> > > +}
> > > +
> > > void pcie_cap_slot_write_config(PCIDevice *dev,
> > > uint16_t old_slt_ctl, uint16_t
> > > old_slt_sta,
> > > uint32_t addr, uint32_t val, int len)
> > > {
> > > + PCIESlot *slot = PCIE_SLOT(dev);
> > > uint32_t pos = dev->exp.exp_cap;
> > > uint8_t *exp_cap = dev->config + pos;
> > > uint16_t sltsta = pci_get_word(exp_cap + PCI_EXP_SLTSTA);
> > > + bool may_unplug;
> > >
> > > if (ranges_overlap(addr, len, pos + PCI_EXP_SLTSTA, 2)) {
> > > /*
> > > @@ -660,22 +693,17 @@ void pcie_cap_slot_write_config(PCIDevice *dev,
> > > * this is a work around for guests that overwrite
> > > * control of powered off slots before powering them on.
> > > */
> > > - if ((sltsta & PCI_EXP_SLTSTA_PDS) && (val & PCI_EXP_SLTCTL_PCC) &&
> > > - (val & PCI_EXP_SLTCTL_PIC_OFF) == PCI_EXP_SLTCTL_PIC_OFF &&
> > > + may_unplug = (val & PCI_EXP_SLTCTL_PCC) &&
> > > + (val & PCI_EXP_SLTCTL_PIC_OFF) ==
> > > PCI_EXP_SLTCTL_PIC_OFF;
> > > + if (may_unplug && (sltsta & PCI_EXP_SLTSTA_PDS) &&
> > > (!(old_slt_ctl & PCI_EXP_SLTCTL_PCC) ||
> > > (old_slt_ctl & PCI_EXP_SLTCTL_PIC_OFF) !=
> > > PCI_EXP_SLTCTL_PIC_OFF)) {
> > > - PCIBus *sec_bus = pci_bridge_get_sec_bus(PCI_BRIDGE(dev));
> > > - pci_for_each_device(sec_bus, pci_bus_num(sec_bus),
> > > - pcie_unplug_device, NULL);
> > > -
> > > - pci_word_test_and_clear_mask(exp_cap + PCI_EXP_SLTSTA,
> > > - PCI_EXP_SLTSTA_PDS);
> > > - if (dev->cap_present & QEMU_PCIE_LNKSTA_DLLLA) {
> > > - pci_word_test_and_clear_mask(exp_cap + PCI_EXP_LNKSTA,
> > > - PCI_EXP_LNKSTA_DLLLA);
> > > + slot->unplug_is_deferred = !migration_is_idle();
> > > + if (!slot->unplug_is_deferred) {
> > > + pcie_cap_slot_unplug(dev);
> > > }
> > > - pci_word_test_and_set_mask(exp_cap + PCI_EXP_SLTSTA,
> > > - PCI_EXP_SLTSTA_PDC);
> > > + } else if (!may_unplug) {
> > > + slot->unplug_is_deferred = false;
> > > }
> > >
> > > hotplug_event_notify(dev);
> > > diff --git a/hw/pci/pcie_port.c b/hw/pci/pcie_port.c
> > > index c19a9be592..bd5fbf6827 100644
> > > --- a/hw/pci/pcie_port.c
> > > +++ b/hw/pci/pcie_port.c
> > > @@ -23,6 +23,9 @@
> > > #include "hw/qdev-properties.h"
> > > #include "qemu/module.h"
> > > #include "hw/hotplug.h"
> > > +#include "sysemu/runstate.h"
> > > +#include "migration/migration.h"
> > > +#include "migration/misc.h"
> > >
> > > void pcie_port_init_reg(PCIDevice *d)
> > > {
> > > @@ -150,6 +153,48 @@ static Property pcie_slot_props[] = {
> > > DEFINE_PROP_END_OF_LIST()
> > > };
> > >
> > > +bool vmstate_deffered_unplug_needed(void *opaque)
> > > +{
> > > + PCIESlot *slot = opaque;
> > > +
> > > + return slot->unplug_is_deferred;
> > > +}
> > > +
> > > +static void pcie_slot_migration_notifier_cb(Notifier *notifier, void
> > > *data)
> > > +{
> > > + PCIESlot *slot = container_of(notifier, PCIESlot,
> > > migration_notifier);
> > > +
> > > + pcie_cap_slot_deferred_unplug(PCI_DEVICE(slot));
> > > +}
> > > +
> > > +static void pcie_slot_vm_state_change(void *opaque, int running,
> > > RunState state)
> > > +{
> > > + PCIESlot *slot = opaque;
> > > +
> > > + pcie_cap_slot_deferred_unplug(PCI_DEVICE(slot));
> > > +}
> > > +
> > > +static void pcie_slot_init(Object *obj)
> > > +{
> > > + PCIESlot *slot = PCIE_SLOT(obj);
> > > +
> > > + slot->unplug_is_deferred = false;
> > > + slot->migration_notifier = (Notifier) {
> > > + .notify = pcie_slot_migration_notifier_cb
> > > + };
> > > + add_migration_state_change_notifier(&slot->migration_notifier);
> > > + slot->vmstate_change =
> > > + qemu_add_vm_change_state_handler(pcie_slot_vm_state_change,
> > > slot);
> > > +}
> > > +
> > > +static void pcie_slot_finalize(Object *obj)
> > > +{
> > > + PCIESlot *slot = PCIE_SLOT(obj);
> > > +
> > > + remove_migration_state_change_notifier(&slot->migration_notifier);
> > > + qemu_del_vm_change_state_handler(slot->vmstate_change);
> > > +}
> > > +
> > > static void pcie_slot_class_init(ObjectClass *oc, void *data)
> > > {
> > > DeviceClass *dc = DEVICE_CLASS(oc);
> > > @@ -166,6 +211,8 @@ static const TypeInfo pcie_slot_type_info = {
> > > .name = TYPE_PCIE_SLOT,
> > > .parent = TYPE_PCIE_PORT,
> > > .instance_size = sizeof(PCIESlot),
> > > + .instance_init = pcie_slot_init,
> > > + .instance_finalize = pcie_slot_finalize,
> > > .abstract = true,
> > > .class_init = pcie_slot_class_init,
> > > .interfaces = (InterfaceInfo[]) {
> > > diff --git a/include/hw/pci/pcie.h b/include/hw/pci/pcie.h
> > > index 7064875835..128f26199e 100644
> > > --- a/include/hw/pci/pcie.h
> > > +++ b/include/hw/pci/pcie.h
> > > @@ -110,6 +110,7 @@ void pcie_cap_slot_get(PCIDevice *dev, uint16_t
> > > *slt_ctl, uint16_t *slt_sta);
> > > void pcie_cap_slot_write_config(PCIDevice *dev,
> > > uint16_t old_slt_ctl, uint16_t
> > > old_slt_sta,
> > > uint32_t addr, uint32_t val, int len);
> > > +void pcie_cap_slot_deferred_unplug(PCIDevice *dev);
> > > int pcie_cap_slot_post_load(void *opaque, int version_id);
> > > void pcie_cap_slot_push_attention_button(PCIDevice *dev);
> > >
> > > diff --git a/include/hw/pci/pcie_port.h b/include/hw/pci/pcie_port.h
> > > index 7515430087..32e45f0c89 100644
> > > --- a/include/hw/pci/pcie_port.h
> > > +++ b/include/hw/pci/pcie_port.h
> > > @@ -23,6 +23,9 @@
> > >
> > > #include "hw/pci/pci_bridge.h"
> > > #include "hw/pci/pci_bus.h"
> > > +#include "qemu/notify.h"
> > > +#include "sysemu/sysemu.h"
> > > +#include "migration/vmstate.h"
> > >
> > > #define TYPE_PCIE_PORT "pcie-port"
> > > #define PCIE_PORT(obj) OBJECT_CHECK(PCIEPort, (obj), TYPE_PCIE_PORT)
> > > @@ -44,6 +47,10 @@ void pcie_port_init_reg(PCIDevice *d);
> > > struct PCIESlot {
> > > /*< private >*/
> > > PCIEPort parent_obj;
> > > + bool unplug_is_deferred;
> > > + Notifier migration_notifier;
> > > + VMChangeStateEntry *vmstate_change;
> > > +
> > > /*< public >*/
> > >
> > > /* pci express switch port with slot */
> > > @@ -58,6 +65,19 @@ struct PCIESlot {
> > > QLIST_ENTRY(PCIESlot) next;
> > > };
> > >
> > > +bool vmstate_deffered_unplug_needed(void *opaque);
> > > +
> > > +#define VMSTATE_DEFFERED_UNPLUG(parent_section_name) { \
> > > + .name = parent_section_name "/deffered-unplug", \
> > > + .version_id = 1, \
> > > + .minimum_version_id = 1, \
> > > + .needed = vmstate_deffered_unplug_needed, \
> > > + .fields = (VMStateField[]) { \
> > > + VMSTATE_BOOL(unplug_is_deferred, PCIESlot), \
> > > + VMSTATE_END_OF_LIST() \
> > > + } \
> > > +}
> > > +
> > > void pcie_chassis_create(uint8_t chassis_number);
> > > PCIESlot *pcie_chassis_find_slot(uint8_t chassis, uint16_t slot);
> > > int pcie_chassis_add_slot(struct PCIESlot *slot);
> > > --
> > > 2.24.1
> > >
> > >
> >
> --
> Dr. David Alan Gilbert / address@hidden / Manchester, UK
>