From 660e8ec70065c8b1fd68b2cb137de16d831959f4 Mon Sep 17 00:00:00 2001 From: Zhu Guihua Date: Mon, 27 Apr 2015 16:47:20 +0800 Subject: [PATCH] acpi: fix "Memory device control fields" register 0 bit in Memory device control fields must be cleared before writing to register. But now this field isn't cleared when other fields are written. To solve this bug, This patch fixes UpdateRule to WriteAsZeros in "Memory device control fields" register. Reviewed-by: Igor Mammedov Signed-off-by: Zhu Guihua Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin --- docs/specs/acpi_mem_hotplug.txt | 5 ++++- hw/i386/acpi-build.c | 2 +- 2 files changed, 5 insertions(+), 2 deletions(-) diff --git a/docs/specs/acpi_mem_hotplug.txt b/docs/specs/acpi_mem_hotplug.txt index dcc4808918..68daa14764 100644 --- a/docs/specs/acpi_mem_hotplug.txt +++ b/docs/specs/acpi_mem_hotplug.txt @@ -31,7 +31,10 @@ Memory hot-plug interface (IO port 0xa00-0xa17, 1-4 byte access): [0xc-0x13] reserved, writes into it are ignored [0x14] Memory device control fields bits: - 0: reserved, OSPM must clear it before writing to register + 0: reserved, OSPM must clear it before writing to register. + Due to BUG in versions prior 2.4 that field isn't cleared + when other fields are written. Keep it reserved and don't + try to reuse it. 1: if set to 1 clears device insert event, set by OSPM after it has emitted device check event for the selected memory device diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c index 085dc6d9e5..4202d76f93 100644 --- a/hw/i386/acpi-build.c +++ b/hw/i386/acpi-build.c @@ -872,7 +872,7 @@ build_ssdt(GArray *table_data, GArray *linker, aml_append(scope, field); field = aml_field(stringify(MEMORY_HOTPLUG_IO_REGION), aml_byte_acc, - aml_preserve); + aml_write_as_zeros); aml_append(field, aml_reserved_field(160 /* bits, Offset(20) */)); aml_append(field, /* 1 if enabled, read only */ aml_named_field(stringify(MEMORY_SLOT_ENABLED), 1)); -- 2.30.2