Commit 3a61c8db9d introduced CPHP_GET_CPU_ID_CMD command but
did not sufficiently describe it. Fix it by adding missing command
documentation.
Fixes: 3a61c8db9d ("acpi: cpuhp: add CPHP_GET_CPU_ID_CMD command")
Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Message-Id: <1580306781-228371-1-git-send-email-imammedo@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Firmware can enumerate present at boot APs by broadcasting wakeup IPI,
so that woken up secondary CPUs could register them-selves.
However in CPU hotplug case, it would need to know architecture
specific CPU IDs for possible and hotplugged CPUs so it could
prepare environment for and wake hotplugged AP.
Reuse and extend existing CPU hotplug interface to return architecture
specific ID for currently selected CPU in 2 registers:
- lower 32 bits in ACPI_CPU_CMD_DATA_OFFSET_RW
- upper 32 bits in ACPI_CPU_CMD_DATA2_OFFSET_R
On x86, firmware will use CPHP_GET_CPU_ID_CMD for fetching the APIC ID
when handling hotplug SMI.
Later, CPHP_GET_CPU_ID_CMD will be used on ARM to retrieve MPIDR,
which serves the similar to APIC ID purpose.
Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Message-Id: <1575896942-331151-10-git-send-email-imammedo@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Document work-flows for
* enabling/detecting modern CPU hotplug interface
* finding a CPU with pending 'insert/remove' event
* enumerating present and possible CPUs
Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Message-Id: <1575896942-331151-9-git-send-email-imammedo@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
No functional change in practice, patch only aims to properly
document (in spec and code) intended usage of the reserved space.
The new field is to be used for 2 purposes:
- detection of modern CPU hotplug interface using
CPHP_GET_NEXT_CPU_WITH_EVENT_CMD command.
procedure will be described in follow up patch:
"acpi: cpuhp: spec: add typical usecases"
- for returning upper 32 bits of architecture specific CPU ID,
for new CPHP_GET_CPU_ID_CMD command added by follow up patch:
"acpi: cpuhp: add CPHP_GET_CPU_ID_CMD command"
Change is backward compatible with 4.2 and older machines, as field was
unconditionally reserved and always returned 0x0 if modern CPU hotplug
interface was enabled.
Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Message-Id: <1575896942-331151-8-git-send-email-imammedo@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Write section of 'Command data' register should describe what happens
when it's written into. Correct description in case the last stored
'Command field' value is equal to 0, to reflect that currently it's not
supported.
Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Message-Id: <1575896942-331151-7-git-send-email-imammedo@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Correct returned value description in case 'Command field' == 0x0,
it's not PXM but CPU selector value with pending event
In addition describe 0 blanket value in case of not supported
'Command field' value.
Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Message-Id: <1575896942-331151-6-git-send-email-imammedo@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
* Move reserved registers to the top of the section, so reader would be
aware of effects when reading registers description.
* State registers endianness explicitly at the beginning of the section
* Describe registers behavior in case of 'CPU selector' register contains
value that doesn't point to a possible CPU.
Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Message-Id: <1575896942-331151-5-git-send-email-imammedo@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Add description of new CPU hotplug interface.
To switch from from legacy mode into new mode use fact
that write accesses into CPU present bitmap were never
used before and were ignored by QEMU.
So use it to as a way to switch from legacy mode.
That way pc/q35 machine starts in legacy mode and
QEMU generated ACPI tables will switch to new CPU
hotplug interface during runtime.
In case QEMU is started with legacy BIOS (that doesn't
support QEMU generated ACPI tables), legacy CPU hotplug
will remain active and could be used by BIOS built in
ACPI tables for CPU hotplug.
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>
.. use IO port 0cd8-0xcf7 range for CPU present bitmap
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>
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Reviewd-By: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
* introduce processor status bitmask visible to guest at 0xaf00 addr,
where ACPI asl code expects it
* set bit corresponding to APIC ID in processor status bitmask on
receiving CPU hot-plug notification
* trigger CPU hot-plug SCI, to notify guest about CPU hot-plug event
Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>
