From b8622725cf0196f672f272922b0941dc8ba1c408 Mon Sep 17 00:00:00 2001 From: Igor Mammedov Date: Thu, 25 Apr 2013 16:05:25 +0200 Subject: acpi_piix4: Add infrastructure to send CPU hot-plug GPE to guest MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit * 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 Signed-off-by: Andreas Färber --- docs/specs/acpi_cpu_hotplug.txt | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) create mode 100644 docs/specs/acpi_cpu_hotplug.txt (limited to 'docs/specs') diff --git a/docs/specs/acpi_cpu_hotplug.txt b/docs/specs/acpi_cpu_hotplug.txt new file mode 100644 index 0000000000..5dec0c5010 --- /dev/null +++ b/docs/specs/acpi_cpu_hotplug.txt @@ -0,0 +1,22 @@ +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. -- cgit v1.2.1