d01be9927c
This series is an attempt to provide device memory hotplug support on ARM virt platform. This is based on Eric's recent works here[1] and carries some of the pc-dimm related patches dropped from his series. The kernel support for arm64 memory hot add was added recently by Robin and hence the guest kernel should be => 5.0-rc1. NVDIM support is not included currently as we still have an unresolved issue while hot adding NVDIMM[2]. However NVDIMM cold plug patches can be included, but not done for now, for keeping it simple. This makes use of GED device to sent hotplug ACPI events to the Guest. GED code is based on Nemu. Thanks to the efforts of Samuel and Sebastien to add the hardware-reduced support to Nemu using GED device[3]. (Please shout if I got the author/signed-off wrong for those patches or missed any names). This is sanity tested on a HiSilicon ARM64 platform and appreciate any further testing. Note: Attempted adding dimm_pxm test case to bios-tables-test for arm/virt. But noticed the issue decribed here[5]. This is under investigation now. upstream url: https://patchwork.kernel.org/cover/11150345/ Signed-off-by: Keqian Zhu <zhukeqian1@huawei.com>
108 lines
3.4 KiB
Diff
108 lines
3.4 KiB
Diff
From 9c1752703fb8a5b70985cf4c9caabc3388c5953b Mon Sep 17 00:00:00 2001
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From: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
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Date: Wed, 18 Sep 2019 14:06:31 +0100
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Subject: [PATCH] docs/specs: Add ACPI GED documentation
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Documents basic concepts of ACPI Generic Event device(GED)
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and interface between QEMU and the ACPI BIOS.
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Signed-off-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
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Reviewed-by: Eric Auger <eric.auger@redhat.com>
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Message-Id: <20190918130633.4872-10-shameerali.kolothum.thodi@huawei.com>
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Acked-by: Peter Maydell <peter.maydell@linaro.org>
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Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
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Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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---
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docs/specs/acpi_hw_reduced_hotplug.rst | 70 ++++++++++++++++++++++++++
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docs/specs/index.rst | 1 +
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2 files changed, 71 insertions(+)
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create mode 100644 docs/specs/acpi_hw_reduced_hotplug.rst
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diff --git a/docs/specs/acpi_hw_reduced_hotplug.rst b/docs/specs/acpi_hw_reduced_hotplug.rst
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new file mode 100644
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index 0000000000..911a98255b
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--- /dev/null
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+++ b/docs/specs/acpi_hw_reduced_hotplug.rst
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@@ -0,0 +1,70 @@
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+==================================================
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+QEMU and ACPI BIOS Generic Event Device interface
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+==================================================
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+
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+The ACPI *Generic Event Device* (GED) is a HW reduced platform
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+specific device introduced in ACPI v6.1 that handles all platform
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+events, including the hotplug ones. GED is modelled as a device
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+in the namespace with a _HID defined to be ACPI0013. This document
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+describes the interface between QEMU and the ACPI BIOS.
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+
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+GED allows HW reduced platforms to handle interrupts in ACPI ASL
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+statements. It follows a very similar approach to the _EVT method
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+from GPIO events. All interrupts are listed in _CRS and the handler
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+is written in _EVT method. However, the QEMU implementation uses a
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+single interrupt for the GED device, relying on an IO memory region
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+to communicate the type of device affected by the interrupt. This way,
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+we can support up to 32 events with a unique interrupt.
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+
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+**Here is an example,**
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+
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+::
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+
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+ Device (\_SB.GED)
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+ {
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+ Name (_HID, "ACPI0013")
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+ Name (_UID, Zero)
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+ Name (_CRS, ResourceTemplate ()
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+ {
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+ Interrupt (ResourceConsumer, Edge, ActiveHigh, Exclusive, ,, )
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+ {
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+ 0x00000029,
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+ }
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+ })
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+ OperationRegion (EREG, SystemMemory, 0x09080000, 0x04)
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+ Field (EREG, DWordAcc, NoLock, WriteAsZeros)
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+ {
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+ ESEL, 32
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+ }
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+ Method (_EVT, 1, Serialized)
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+ {
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+ Local0 = ESEL // ESEL = IO memory region which specifies the
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+ // device type.
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+ If (((Local0 & One) == One))
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+ {
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+ MethodEvent1()
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+ }
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+ If ((Local0 & 0x2) == 0x2)
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+ {
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+ MethodEvent2()
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+ }
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+ ...
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+ }
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+ }
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+
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+GED IO interface (4 byte access)
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+--------------------------------
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+**read access:**
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+
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+::
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+
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+ [0x0-0x3] Event selector bit field (32 bit) set by QEMU.
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+
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+ bits:
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+ 0: Memory hotplug event
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+ 1: System power down event
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+ 2-31: Reserved
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+
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+**write_access:**
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+
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+Nothing is expected to be written into GED IO memory
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diff --git a/docs/specs/index.rst b/docs/specs/index.rst
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index 40adb97c5e..984ba44029 100644
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--- a/docs/specs/index.rst
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+++ b/docs/specs/index.rst
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@@ -12,3 +12,4 @@ Contents:
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ppc-xive
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ppc-spapr-xive
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+ acpi_hw_reduced_hotplug
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--
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2.19.1
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