We introduce a new global flag 'acpi-root-pci-hotplug' for i440fx with which
we can turn on or off PCI device hotplug on the root bus. This flag can be
used to prevent all PCI devices from getting hotplugged or unplugged from the
root PCI bus.
This feature is targetted mostly towards Windows VMs. It is useful in cases
where some hypervisor admins want to deploy guest VMs in a way so that the
users of the guest OSes are not able to hot-eject certain PCI devices from
the Windows system tray. Laine has explained the use case here in detail:
https://www.redhat.com/archives/libvir-list/2020-February/msg00110.html
Julia has resolved this issue for PCIE buses with the following commit:
530a096318 ("pcie_root_port: Add hotplug disabling option")
This commit attempts to introduce similar behavior for PCI root buses used in
i440fx machine types (although in this case, we do not have a per-slot
capability to turn hotplug on or off).
Usage:
-global PIIX4_PM.acpi-root-pci-hotplug=off
By default, this option is enabled which means that hotplug is turned on for
the PCI root bus.
The previously existing flag 'acpi-pci-hotplug-with-bridge-support' for PCI-PCI
bridges remain as is and can be used along with this new flag to control PCI
hotplug on PCI bridges.
This change has been tested using a Windows 2012R2 server guest image and also
with a Windows 2019 server guest image on a Ubuntu 18.04 host using the latest
master qemu from upstream.
Signed-off-by: Ani Sinha <ani@anisinha.ca>
Message-Id: <20200821165403.26589-1-ani@anisinha.ca>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Tested-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Introduce and use the "unplug" callback.
This is a preparation for multi-stage hotplug handlers, whereby the bus
hotplug handler is overwritten by the machine hotplug handler. This handler
will then pass control to the bus hotplug handler. So to get this running
cleanly, we also have to make sure to go via the hotplug handler chain when
actually unplugging a device after an unplug request. Lookup the hotplug
handler and call "unplug".
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Perform the check in the pre_plug handler. In addition, we need the
capability only if the device is actually hotplugged (and not created
during machine initialization). This is a preparation for coldplugging
pci devices via that hotplug handler.
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
it reduces number of args passed in handlers by 1 and
a number of used proxy wrappers saving ~20LOC.
Also it allows to make cpu/mem hotplug code more
universal as it would allow ARM to reuse it without
rewrite by providing its own send_event callback
to trigger events usiong GPIO instead of GPE
as fixed hadrware ACPI model doen't have GPE at all.
Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Manually drop redundant includes that scripts/clean-includes misses,
e.g. because they're hidden in generator programs, or they use the
wrong kind of delimiter.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Clean up includes so that osdep.h is included first and headers
which it implies are not included manually.
This commit was created with scripts/clean-includes.
NB: If this commit breaks compilation for your out-of-tree
patchseries or fork, then you need to make sure you add
#include "qemu/osdep.h" to any new .c files that you have.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Eric Blake <eblake@redhat.com>
it will be used later to dynamically reserve MMIO region
instead of manually punching holes in PCI0._CRS
Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Split piix4_device_hotplug() into hotplug/unplug callbacks
and register them as "hotplug-handler" interface implementation of
PIIX4_PM device.
Replace pci_bus_hotplug() wiring with setting link on
PCI BUS "hotplug-handler" property to PIIX4_PM device.
Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
reduces acpi PCI hotplug code duplication by ~200LOC
Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Remove now unused 'device_present' field wich was obsoleted by
patch "pcihp: reduce number of device check events"
Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
due to recent change introduced by:
"pcihp: reduce number of device check events"
'up' field is cleared right after it's read.
This is incompatible with legacy BIOS ACPI code
where PCNF ACPI method reads this field 32 times.
To make pci_read mmio callback compatible with legacy
'up' behavior, pcihp code will need to know in which
mode it runs add 'legacy_piix' field to AcpiPciHpState
structure and alter register behavior accordingly.
Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
PIIX created a made-up value for the UP register since it was read by
guest 32 times for each interrupt.
There's no reason to do this for the new PCIHP: register is only read
once for each interrupt, so clean up code by making read act as an
interrupt acknowledgement: the new UP register clear on read.
In this way we cut down the number of bus rescans
by a factor of 32, and drop a bunch of code that's
now unused.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Add ACPI based PCI hotplug library with bridge hotplug
support.
Design
- each bus gets assigned "bsel" property.
- ACPI code writes this number
to a new BNUM register, then uses existing
UP/DOWN registers to probe slot status;
to eject, write number to BNUM register,
then slot into existing EJ.
The interface is actually backwards-compatible with
existing PIIX4 ACPI (though not migration compatible).
This is split out from PIIX4 codebase so we can
reuse it for Q35 as well.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
