qemu/hw/acpi/pci.c
Igor Mammedov b32bd763a1 pci: introduce acpi-index property for PCI device
In x86/ACPI world, linux distros are using predictable
network interface naming since systemd v197. Which on
QEMU based VMs results into path based naming scheme,
that names network interfaces based on PCI topology.

With itm on has to plug NIC in exactly the same bus/slot,
which was used when disk image was first provisioned/configured
or one risks to loose network configuration due to NIC being
renamed to actually used topology.
That also restricts freedom to reshape PCI configuration of
VM without need to reconfigure used guest image.

systemd also offers "onboard" naming scheme which is
preferred over PCI slot/topology one, provided that
firmware implements:
    "
    PCI Firmware Specification 3.1
    4.6.7.  DSM for Naming a PCI or PCI Express Device Under
            Operating Systems
    "
that allows to assign user defined index to PCI device,
which systemd will use to name NIC. For example, using
  -device e1000,acpi-index=100
guest will rename NIC to 'eno100', where 'eno' is default
prefix for "onboard" naming scheme. This doesn't require
any advance configuration on guest side to com in effect
at 'onboard' scheme takes priority over path based naming.

Hope is that 'acpi-index' it will be easier to consume by
management layer, compared to forcing specific PCI topology
and/or having several disk image templates for different
topologies and will help to simplify process of spawning
VM from the same template without need to reconfigure
guest NIC.

This patch adds, 'acpi-index'* property and wires up
a 32bit register on top of pci hotplug register block
to pass index value to AML code at runtime.
Following patch will add corresponding _DSM code and
wire it up to PCI devices described in ACPI.

*) name comes from linux kernel terminology

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Message-Id: <20210315180102.3008391-3-imammedo@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2021-03-22 18:58:19 -04:00

62 lines
2.2 KiB
C

/*
* Support for generating PCI related ACPI tables and passing them to Guests
*
* Copyright (C) 2006 Fabrice Bellard
* Copyright (C) 2008-2010 Kevin O'Connor <kevin@koconnor.net>
* Copyright (C) 2013-2019 Red Hat Inc
* Copyright (C) 2019 Intel Corporation
*
* Author: Wei Yang <richardw.yang@linux.intel.com>
* Author: Michael S. Tsirkin <mst@redhat.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
* You should have received a copy of the GNU General Public License along
* with this program; if not, see <http://www.gnu.org/licenses/>.
*/
#include "qemu/osdep.h"
#include "hw/acpi/aml-build.h"
#include "hw/acpi/pci.h"
#include "hw/pci/pcie_host.h"
void build_mcfg(GArray *table_data, BIOSLinker *linker, AcpiMcfgInfo *info,
const char *oem_id, const char *oem_table_id)
{
int mcfg_start = table_data->len;
/*
* PCI Firmware Specification, Revision 3.0
* 4.1.2 MCFG Table Description.
*/
acpi_data_push(table_data, sizeof(AcpiTableHeader));
/* Reserved */
build_append_int_noprefix(table_data, 0, 8);
/*
* Memory Mapped Enhanced Configuration Space Base Address Allocation
* Structure
*/
/* Base address, processor-relative */
build_append_int_noprefix(table_data, info->base, 8);
/* PCI segment group number */
build_append_int_noprefix(table_data, 0, 2);
/* Starting PCI Bus number */
build_append_int_noprefix(table_data, 0, 1);
/* Final PCI Bus number */
build_append_int_noprefix(table_data, PCIE_MMCFG_BUS(info->size - 1), 1);
/* Reserved */
build_append_int_noprefix(table_data, 0, 4);
build_header(linker, table_data, (void *)(table_data->data + mcfg_start),
"MCFG", table_data->len - mcfg_start, 1, oem_id, oem_table_id);
}