From: "Michael S. Tsirkin" <mst@redhat.com>
To: qemu-devel@nongnu.org
Cc: Peter Maydell <peter.maydell@linaro.org>,
Laszlo Ersek <lersek@redhat.com>,
Igor Mammedov <imammedo@redhat.com>
Subject: [PULL 03/17] acpi: cpuhp: spec: clarify 'CPU selector' register usage and endianness
Date: Wed, 22 Jan 2020 00:51:54 -0500 [thread overview]
Message-ID: <20200122055115.429945-4-mst@redhat.com> (raw)
In-Reply-To: <20200122055115.429945-1-mst@redhat.com>
From: Igor Mammedov <imammedo@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>
---
docs/specs/acpi_cpu_hotplug.txt | 18 ++++++++++++------
1 file changed, 12 insertions(+), 6 deletions(-)
diff --git a/docs/specs/acpi_cpu_hotplug.txt b/docs/specs/acpi_cpu_hotplug.txt
index ee219c8358..4e65286ff5 100644
--- a/docs/specs/acpi_cpu_hotplug.txt
+++ b/docs/specs/acpi_cpu_hotplug.txt
@@ -30,6 +30,18 @@ Register block base address:
Register block size:
ACPI_CPU_HOTPLUG_REG_LEN = 12
+All accesses to registers described below, imply little-endian byte order.
+
+Reserved resisters behavior:
+ - write accesses are ignored
+ - read accesses return all bits set to 0.
+
+The last stored value in 'CPU selector' must refer to a possible CPU, otherwise
+ - reads from any register return 0
+ - writes to any other register are ignored until valid value is stored into it
+On QEMU start, 'CPU selector' is initialized to a valid value, on reset it
+keeps the current value.
+
read access:
offset:
[0x0-0x3] reserved
@@ -86,9 +98,3 @@ write access:
ACPI_DEVICE_OST QMP event from QEMU to external applications
with current values of OST event and status registers.
other values: reserved
-
-Selecting CPU device beyond possible range has no effect on platform:
- - write accesses to CPU hot-plug registers not documented above are
- ignored
- - read accesses to CPU hot-plug registers not documented above return
- all bits set to 0.
--
MST
next prev parent reply other threads:[~2020-01-22 5:56 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-22 5:51 [PULL 00/17] virtio, pc: fixes, features Michael S. Tsirkin
2020-01-22 5:51 ` [PULL 01/17] q35: implement 128K SMRAM at default SMBASE address Michael S. Tsirkin
2020-01-22 5:51 ` [PULL 02/17] tests: q35: MCH: add default SMBASE SMRAM lock test Michael S. Tsirkin
2020-01-22 5:51 ` Michael S. Tsirkin [this message]
2020-01-22 5:51 ` [PULL 04/17] acpi: cpuhp: spec: fix 'Command data' description Michael S. Tsirkin
2020-01-22 5:52 ` [PULL 05/17] acpi: cpuhp: spec: clarify store into 'Command data' when 'Command field' == 0 Michael S. Tsirkin
2020-01-22 5:52 ` [PULL 06/17] acpi: cpuhp: introduce 'Command data 2' field Michael S. Tsirkin
2020-01-22 5:52 ` [PULL 07/17] acpi: cpuhp: spec: add typical usecases Michael S. Tsirkin
2020-01-22 5:52 ` [PULL 08/17] acpi: cpuhp: add CPHP_GET_CPU_ID_CMD command Michael S. Tsirkin
2020-01-22 5:52 ` [PULL 09/17] bios-tables-test: document expected file update Michael S. Tsirkin
2020-01-22 5:52 ` [PULL 10/17] virtio-9p-device: fix memleak in virtio_9p_device_unrealize Michael S. Tsirkin
2020-01-22 5:52 ` [PULL 11/17] virtio-9p-device: convert to new virtio_delete_queue Michael S. Tsirkin
2020-01-22 5:52 ` [PULL 12/17] virtio-scsi: delete vqs in unrealize to avoid memleaks Michael S. Tsirkin
2020-01-22 5:52 ` [PULL 13/17] virtio-scsi: convert to new virtio_delete_queue Michael S. Tsirkin
2020-01-22 5:52 ` [PULL 14/17] vhost-vsock: delete vqs in vhost_vsock_unrealize to avoid memleaks Michael S. Tsirkin
2020-01-22 5:52 ` [PULL 15/17] vhost: Add names to section rounded warning Michael S. Tsirkin
2020-01-22 5:52 ` [PULL 16/17] vhost: Only align sections for vhost-user Michael S. Tsirkin
2020-01-22 5:52 ` [PULL 17/17] i386:acpi: Remove _HID from the SMBus ACPI entry Michael S. Tsirkin
2020-01-22 6:17 ` [PULL 00/17] virtio, pc: fixes, features no-reply
2020-01-22 6:23 ` no-reply
2020-01-22 6:25 ` Michael S. Tsirkin
2020-01-22 6:50 ` Michael S. Tsirkin
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