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authorIgor Mammedov <imammedo@redhat.com>2013-04-25 16:05:25 +0200
committerAndreas Färber <afaerber@suse.de>2013-05-01 13:04:18 +0200
commitb8622725cf0196f672f272922b0941dc8ba1c408 (patch)
treef33cacb399cb67622dd53a98240ac7073ceb0ad4 /docs/specs
parent69e5ff067ae724155fd7465119ee6db5721288b6 (diff)
acpi_piix4: Add infrastructure to send CPU hot-plug GPE to guest
* 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>
Diffstat (limited to 'docs/specs')
-rw-r--r--docs/specs/acpi_cpu_hotplug.txt22
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diff --git a/docs/specs/acpi_cpu_hotplug.txt b/docs/specs/acpi_cpu_hotplug.txt
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+QEMU<->ACPI BIOS CPU hotplug interface
+--------------------------------------
+
+QEMU supports CPU hotplug via ACPI. This document
+describes the interface between QEMU and the ACPI BIOS.
+
+ACPI GPE block (IO ports 0xafe0-0xafe3, byte access):
+-----------------------------------------
+
+Generic ACPI GPE block. Bit 2 (GPE.2) used to notify CPU
+hot-add/remove event to ACPI BIOS, via SCI interrupt.
+
+CPU present bitmap (IO port 0xaf00-0xae1f, 1-byte access):
+---------------------------------------------------------------
+One bit per CPU. Bit position reflects corresponding CPU APIC ID.
+Read-only.
+
+CPU hot-add/remove notification:
+-----------------------------------------------------
+QEMU sets/clears corresponding CPU bit on hot-add/remove event.
+CPU present map read by ACPI BIOS GPE.2 handler to notify OS of CPU
+hot-(un)plug events.