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>

diff --git a/hw/acpi/pci.c b/hw/acpi/pci.c
index ec455c3b25c09e341d3ca200fed8a04b91c4be61..75b1103ec45d690d9ba234b3252cec43cbae4fcd 100644 (file)
--- a/hw/acpi/pci.c
+++ b/hw/acpi/pci.c
@@ -59,4 +59,3 @@ void build_mcfg(GArray *table_data, BIOSLinker *linker, AcpiMcfgInfo *info,
     build_header(linker, table_data, (void *)(table_data->data + mcfg_start),
                  "MCFG", table_data->len - mcfg_start, 1, oem_id, oem_table_id);
 }
-

diff --git a/hw/acpi/pcihp.c b/hw/acpi/pcihp.c
index 9dc4d3e2dbeda7660d1395bf9e9d5f14378690f4..ceab287bd31a1321014416b1ec0c9747bb2b1372 100644 (file)
--- a/hw/acpi/pcihp.c
+++ b/hw/acpi/pcihp.c
@@ -39,12 +39,13 @@
 #include "trace.h"
 
 #define ACPI_PCIHP_ADDR 0xae00
-#define ACPI_PCIHP_SIZE 0x0014
+#define ACPI_PCIHP_SIZE 0x0018
 #define PCI_UP_BASE 0x0000
 #define PCI_DOWN_BASE 0x0004
 #define PCI_EJ_BASE 0x0008
 #define PCI_RMV_BASE 0x000c
 #define PCI_SEL_BASE 0x0010
+#define PCI_AIDX_BASE 0x0014
 
 typedef struct AcpiPciHpFind {
     int bsel;
@@ -251,9 +252,13 @@ void acpi_pcihp_reset(AcpiPciHpState *s, bool acpihp_root_off)
     acpi_pcihp_update(s);
 }
 
+#define ONBOARD_INDEX_MAX (16 * 1024 - 1)
+
 void acpi_pcihp_device_pre_plug_cb(HotplugHandler *hotplug_dev,
                                    DeviceState *dev, Error **errp)
 {
+    PCIDevice *pdev = PCI_DEVICE(dev);
+
     /* Only hotplugged devices need the hotplug capability. */
     if (dev->hotplugged &&
         acpi_pcihp_get_bsel(pci_get_bus(PCI_DEVICE(dev))) < 0) {
@@ -261,6 +266,17 @@ void acpi_pcihp_device_pre_plug_cb(HotplugHandler *hotplug_dev,
                    ACPI_PCIHP_PROP_BSEL "' set");
         return;
     }
+
+    /*
+     * capped by systemd (see: udev-builtin-net_id.c)
+     * as it's the only known user honor it to avoid users
+     * misconfigure QEMU and then wonder why acpi-index doesn't work
+     */
+    if (pdev->acpi_index > ONBOARD_INDEX_MAX) {
+        error_setg(errp, "acpi-index should be less or equal to %u",
+                   ONBOARD_INDEX_MAX);
+        return;
+    }
 }
 
 void acpi_pcihp_device_plug_cb(HotplugHandler *hotplug_dev, AcpiPciHpState *s,
@@ -347,7 +363,6 @@ static uint64_t pci_read(void *opaque, hwaddr addr, unsigned int size)
         trace_acpi_pci_down_read(val);
         break;
     case PCI_EJ_BASE:
-        /* No feature defined yet */
         trace_acpi_pci_features_read(val);
         break;
     case PCI_RMV_BASE:
@@ -357,6 +372,12 @@ static uint64_t pci_read(void *opaque, hwaddr addr, unsigned int size)
     case PCI_SEL_BASE:
         val = s->hotplug_select;
         trace_acpi_pci_sel_read(val);
+        break;
+    case PCI_AIDX_BASE:
+        val = s->acpi_index;
+        s->acpi_index = 0;
+        trace_acpi_pci_acpi_index_read(val);
+        break;
     default:
         break;
     }
@@ -367,8 +388,35 @@ static uint64_t pci_read(void *opaque, hwaddr addr, unsigned int size)
 static void pci_write(void *opaque, hwaddr addr, uint64_t data,
                       unsigned int size)
 {
+    int slot;
+    PCIBus *bus;
+    BusChild *kid, *next;
     AcpiPciHpState *s = opaque;
+
+    s->acpi_index = 0;
     switch (addr) {
+    case PCI_AIDX_BASE:
+        /*
+         * fetch acpi-index for specified slot so that follow up read from
+         * PCI_AIDX_BASE can return it to guest
+         */
+        slot = ctz32(data);
+
+        if (s->hotplug_select >= ACPI_PCIHP_MAX_HOTPLUG_BUS) {
+            break;
+        }
+
+        bus = acpi_pcihp_find_hotplug_bus(s, s->hotplug_select);
+        QTAILQ_FOREACH_SAFE(kid, &bus->qbus.children, sibling, next) {
+            Object *o = OBJECT(kid->child);
+            PCIDevice *dev = PCI_DEVICE(o);
+            if (PCI_SLOT(dev->devfn) == slot) {
+                s->acpi_index = object_property_get_uint(o, "acpi-index", NULL);
+                break;
+            }
+        }
+        trace_acpi_pci_acpi_index_write(s->hotplug_select, slot, s->acpi_index);
+        break;
     case PCI_EJ_BASE:
         if (s->hotplug_select >= ACPI_PCIHP_MAX_HOTPLUG_BUS) {
             break;
@@ -413,6 +461,12 @@ void acpi_pcihp_init(Object *owner, AcpiPciHpState *s, PCIBus *root_bus,
                                    OBJ_PROP_FLAG_READ);
 }
 
+bool vmstate_acpi_pcihp_use_acpi_index(void *opaque, int version_id)
+{
+     AcpiPciHpState *s = opaque;
+     return s->acpi_index;
+}
+
 const VMStateDescription vmstate_acpi_pcihp_pci_status = {
     .name = "acpi_pcihp_pci_status",
     .version_id = 1,

diff --git a/hw/acpi/piix4.c b/hw/acpi/piix4.c
index 1efc0ded9f60f25ba69e8b0f0c84d7cc39655dac..6056d51667bbfeafcd80f3b6e28bb5a86f3a7508 100644 (file)
--- a/hw/acpi/piix4.c
+++ b/hw/acpi/piix4.c
@@ -297,7 +297,8 @@ static const VMStateDescription vmstate_acpi = {
             2, vmstate_pci_status,
             struct AcpiPciHpPciStatus),
         VMSTATE_PCI_HOTPLUG(acpi_pci_hotplug, PIIX4PMState,
-                            vmstate_test_use_acpi_hotplug_bridge),
+                            vmstate_test_use_acpi_hotplug_bridge,
+                            vmstate_acpi_pcihp_use_acpi_index),
         VMSTATE_END_OF_LIST()
     },
     .subsections = (const VMStateDescription*[]) {

diff --git a/hw/acpi/trace-events b/hw/acpi/trace-events
index f91ced477d4bd59e04193107128958f8feff4092..dcc1438f3a069b9c42c65dff3076315ec20565c7 100644 (file)
--- a/hw/acpi/trace-events
+++ b/hw/acpi/trace-events
@@ -41,6 +41,8 @@ acpi_pci_unplug_request(int bsel, int slot) "bsel: %d slot: %d"
 acpi_pci_up_read(uint32_t val) "%" PRIu32
 acpi_pci_down_read(uint32_t val) "%" PRIu32
 acpi_pci_features_read(uint32_t val) "%" PRIu32
+acpi_pci_acpi_index_read(uint32_t val) "%" PRIu32
+acpi_pci_acpi_index_write(unsigned bsel, unsigned slot, uint32_t aidx) "bsel: %u slot: %u aidx: %" PRIu32
 acpi_pci_rmv_read(uint32_t val) "%" PRIu32
 acpi_pci_sel_read(uint32_t val) "%" PRIu32
 acpi_pci_ej_write(uint64_t addr, uint64_t data) "0x%" PRIx64 " <== %" PRIu64

diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
index 442b4629a9416ffe6586d0d9e1fa75918aa41c8d..e49fae2bfd35b3a6c48dea1535358d6b9c39bc40 100644 (file)
--- a/hw/i386/acpi-build.c
+++ b/hw/i386/acpi-build.c
@@ -1168,9 +1168,10 @@ static void build_piix4_pci_hotplug(Aml *table)
     aml_append(scope, field);
 
     aml_append(scope,
-        aml_operation_region("BNMR", AML_SYSTEM_IO, aml_int(0xae10), 0x04));
+        aml_operation_region("BNMR", AML_SYSTEM_IO, aml_int(0xae10), 0x08));
     field = aml_field("BNMR", AML_DWORD_ACC, AML_NOLOCK, AML_WRITE_AS_ZEROS);
     aml_append(field, aml_named_field("BNUM", 32));
+    aml_append(field, aml_named_field("PIDX", 32));
     aml_append(scope, field);
 
     aml_append(scope, aml_mutex("BLCK", 0));
@@ -1184,6 +1185,16 @@ static void build_piix4_pci_hotplug(Aml *table)
     aml_append(method, aml_return(aml_int(0)));
     aml_append(scope, method);
 
+    method = aml_method("AIDX", 2, AML_NOTSERIALIZED);
+    aml_append(method, aml_acquire(aml_name("BLCK"), 0xFFFF));
+    aml_append(method, aml_store(aml_arg(0), aml_name("BNUM")));
+    aml_append(method,
+        aml_store(aml_shiftleft(aml_int(1), aml_arg(1)), aml_name("PIDX")));
+    aml_append(method, aml_store(aml_name("PIDX"), aml_local(0)));
+    aml_append(method, aml_release(aml_name("BLCK")));
+    aml_append(method, aml_return(aml_local(0)));
+    aml_append(scope, method);
+
     aml_append(table, scope);
 }
 

diff --git a/hw/pci/pci.c b/hw/pci/pci.c
index 0eadcdbc9ec1dff6e0aaa37b9807685b648db508..ac9a24889c72ce0f773170a4506e2925b304de38 100644 (file)
--- a/hw/pci/pci.c
+++ b/hw/pci/pci.c
@@ -79,6 +79,7 @@ static Property pci_props[] = {
                     QEMU_PCIE_EXTCAP_INIT_BITNR, true),
     DEFINE_PROP_STRING("failover_pair_id", PCIDevice,
                        failover_pair_id),
+    DEFINE_PROP_UINT32("acpi-index",  PCIDevice, acpi_index, 0),
     DEFINE_PROP_END_OF_LIST()
 };
 

diff --git a/include/hw/acpi/pcihp.h b/include/hw/acpi/pcihp.h
index dfd375820f87e97caeba6f9764b4cba01b7ce377..2dd90aea309140cda318f2a39d0e74582362ac62 100644 (file)
--- a/include/hw/acpi/pcihp.h
+++ b/include/hw/acpi/pcihp.h
@@ -46,6 +46,7 @@ typedef struct AcpiPciHpPciStatus {
 typedef struct AcpiPciHpState {
     AcpiPciHpPciStatus acpi_pcihp_pci_status[ACPI_PCIHP_MAX_HOTPLUG_BUS];
     uint32_t hotplug_select;
+    uint32_t acpi_index;
     PCIBus *root;
     MemoryRegion io;
     bool legacy_piix;
@@ -71,13 +72,17 @@ void acpi_pcihp_reset(AcpiPciHpState *s, bool acpihp_root_off);
 
 extern const VMStateDescription vmstate_acpi_pcihp_pci_status;
 
-#define VMSTATE_PCI_HOTPLUG(pcihp, state, test_pcihp) \
+bool vmstate_acpi_pcihp_use_acpi_index(void *opaque, int version_id);
+
+#define VMSTATE_PCI_HOTPLUG(pcihp, state, test_pcihp, test_acpi_index) \
         VMSTATE_UINT32_TEST(pcihp.hotplug_select, state, \
                             test_pcihp), \
         VMSTATE_STRUCT_ARRAY_TEST(pcihp.acpi_pcihp_pci_status, state, \
                                   ACPI_PCIHP_MAX_HOTPLUG_BUS, \
                                   test_pcihp, 1, \
                                   vmstate_acpi_pcihp_pci_status, \
-                                  AcpiPciHpPciStatus)
+                                  AcpiPciHpPciStatus), \
+        VMSTATE_UINT32_TEST(pcihp.acpi_index, state, \
+                            test_acpi_index)
 
 #endif

diff --git a/include/hw/pci/pci.h b/include/hw/pci/pci.h
index 1bc231480fd7acc7d668edbe3060c5f2cbc36f16..6be4e0c460c5a1daaaba8455f51bc876b23533a1 100644 (file)
--- a/include/hw/pci/pci.h
+++ b/include/hw/pci/pci.h
@@ -359,6 +359,7 @@ struct PCIDevice {
 
     /* ID of standby device in net_failover pair */
     char *failover_pair_id;
+    uint32_t acpi_index;
 };
 
 void pci_register_bar(PCIDevice *pci_dev, int region_num,