vdpa: Introduce VDPASetAttr, support setting mac

The Linux kernel supports setting mac addresses to existing vdpa devices
since 6.12. The feature was introduced by commit 2f87e9cf.

This commit brings support for that feature to the netlink library by
introducing the VDPASetAttr function.

Note that even though setting the mac address is the only supported
operation currently, the implementation has been left open for MTU,
MaxVQP and Feature setting. In other words, it relies on whether the
kernel supports it or not, and just feeds the kernel's error back to the
caller. That way, no further changes will be needed in the future, if
support for those operations is implemented. Well, apart from tests, as
they currently assume those are not supported.

Signed-off-by: Beñat Gartzia Arruabarrena <[email protected]>

Author: bgartzi

nl/vdpa_linux.go

@@ -14,6 +14,7 @@ const (
 	VDPA_CMD_DEV_GET        /* can dump */
 	VDPA_CMD_DEV_CONFIG_GET /* can dump */
 	VDPA_CMD_DEV_VSTATS_GET
+	VDPA_CMD_DEV_ATTR_SET
 )
 
 const (

vdpa_linux.go

@@ -168,6 +168,10 @@ func VDPAGetMGMTDevByBusAndName(bus, name string) (*VDPAMGMTDev, error) {
 	return pkgHandle.VDPAGetMGMTDevByBusAndName(bus, name)
 }
 
+func VDPASetAttr(name string, params VDPANewDevParams) error {
+	return pkgHandle.VDPASetAttr(name, params)
+}
+
 type vdpaNetlinkMessage []syscall.NetlinkRouteAttr
 
 func (id *vdpaDevID) parseIDAttribute(attr syscall.NetlinkRouteAttr) {
@@ -489,3 +493,30 @@ func (h *Handle) VDPAGetMGMTDevByBusAndName(bus, name string) (*VDPAMGMTDev, err
 	}
 	return devs[0], nil
 }
+
+// VDPASetAttr sets other values to attributes of a VDPA device
+// Equivalent to: `vdpa dev set name <name> ...`
+func (h *Handle) VDPASetAttr(name string, params VDPANewDevParams) error {
+	attrs := []*nl.RtAttr{}
+
+	if len(params.MACAddr) != 0 {
+		attrs = append(attrs, nl.NewRtAttr(nl.VDPA_ATTR_DEV_NET_CFG_MACADDR, params.MACAddr))
+	}
+	if params.MaxVQP > 0 {
+		attrs = append(attrs, nl.NewRtAttr(nl.VDPA_ATTR_DEV_NET_CFG_MAX_VQP, nl.Uint16Attr(params.MaxVQP)))
+	}
+	if params.MTU > 0 {
+		attrs = append(attrs, nl.NewRtAttr(nl.VDPA_ATTR_DEV_NET_CFG_MTU, nl.Uint16Attr(params.MTU)))
+	}
+	if params.Features > 0 {
+		attrs = append(attrs, nl.NewRtAttr(nl.VDPA_ATTR_DEV_FEATURES, nl.Uint64Attr(params.Features)))
+	}
+
+	if len(attrs) == 0 {
+		return fmt.Errorf("parameters were not provided")
+	}
+	attrs = append(attrs, nl.NewRtAttr(nl.VDPA_ATTR_DEV_NAME, nl.ZeroTerminated(name)))
+
+	_, err := h.vdpaRequest(nl.VDPA_CMD_DEV_ATTR_SET, unix.NLM_F_REQUEST, attrs)
+	return err
+}

vdpa_linux_test.go

@@ -2,6 +2,7 @@ package netlink
 
 import (
 	"errors"
+	"net"
 	"syscall"
 	"testing"
 
@@ -222,6 +223,88 @@ func TestVDPAGetDevConfigByName_Unknowm(t *testing.T) {
 	}
 }
 
+func TestVDPASetMAC(t *testing.T) {
+	defer setupVDPATest(t, nl.VDPA_CMD_DEV_GET, nl.VDPA_CMD_DEV_CONFIG_GET, nl.VDPA_CMD_DEV_ATTR_SET)()
+	firstMac, _ := net.ParseMAC("02:11:22:33:44:68")
+	lastMacStr := "72:84:65:12:09:77"
+	lastMac, _ := net.ParseMAC(lastMacStr)
+	if err := createVDPATestDevWithParams(VDPANewDevParams{MACAddr: firstMac}); err != nil {
+		t.Fatalf("failed to create VDPA device: %v", err)
+	}
+	if err := VDPASetAttr(vdpaTestDeviceName, VDPANewDevParams{MACAddr: lastMac}); err != nil {
+		t.Fatalf("failed to set mac to VDPA device: %v", err)
+	}
+	dev, err := VDPAGetDevConfigByName(vdpaTestDeviceName)
+	if err != nil {
+		t.Fatalf("VDPAGetDevConfigByName failed: %v", err)
+	}
+	checkVDPADevConf(t, dev)
+	if dev.Name != vdpaTestDeviceName {
+		t.Fatalf("Invalid device received for Get call, expected: %s, actual: %s", vdpaTestDeviceName, dev.Name)
+	}
+	newMacStr := dev.Net.Cfg.MACAddr.String()
+	if newMacStr != lastMacStr {
+		t.Fatalf("mac address was not properly set. Expected: %s, actual: %s", lastMac, newMacStr)
+	}
+}
+
+func TestVDPASetMACWrongName(t *testing.T) {
+	defer setupVDPATest(t, nl.VDPA_CMD_DEV_GET, nl.VDPA_CMD_DEV_CONFIG_GET, nl.VDPA_CMD_DEV_ATTR_SET)()
+	mac, _ := net.ParseMAC("72:84:65:12:09:77")
+	if err := createVDPATestDev(); err != nil {
+		t.Fatalf("failed to create VDPA device: %v", err)
+	}
+	err := VDPASetAttr("__unknown_device__", VDPANewDevParams{MACAddr: mac})
+	if !errors.Is(err, syscall.ENODEV) {
+		t.Fatalf("VDPASetAttr returned unexpected error setting mac to non existing device: %v", err)
+	}
+}
+
+func TestVDPASetEmptyParams(t *testing.T) {
+	defer setupVDPATest(t, nl.VDPA_CMD_DEV_GET, nl.VDPA_CMD_DEV_CONFIG_GET, nl.VDPA_CMD_DEV_ATTR_SET)()
+	if err := createVDPATestDev(); err != nil {
+		t.Fatalf("failed to create VDPA device: %v", err)
+	}
+	err := VDPASetAttr(vdpaTestDeviceName, VDPANewDevParams{})
+	if err == nil {
+		t.Fatalf("VDPASetAttr did not return an error when params were empty: %v", err)
+	}
+}
+
+func TestVDPASetMTU(t *testing.T) {
+	defer setupVDPATest(t, nl.VDPA_CMD_DEV_GET, nl.VDPA_CMD_DEV_CONFIG_GET, nl.VDPA_CMD_DEV_ATTR_SET)()
+	if err := createVDPATestDev(); err != nil {
+		t.Fatalf("failed to create VDPA device: %v", err)
+	}
+	err := VDPASetAttr(vdpaTestDeviceName, VDPANewDevParams{MTU: 3000})
+	if !errors.Is(err, syscall.ENOTSUP) {
+		t.Fatalf("VDPASetAttr returned an unexpected error setting mtu to vdpa device: %v", err)
+	}
+}
+
+func TestVDPASetMaxVQP(t *testing.T) {
+	defer setupVDPATest(t, nl.VDPA_CMD_DEV_GET, nl.VDPA_CMD_DEV_CONFIG_GET, nl.VDPA_CMD_DEV_ATTR_SET)()
+	if err := createVDPATestDev(); err != nil {
+		t.Fatalf("failed to create VDPA device: %v", err)
+	}
+	err := VDPASetAttr(vdpaTestDeviceName, VDPANewDevParams{MaxVQP: 3000})
+	if !errors.Is(err, syscall.ENOTSUP) {
+		t.Fatalf("VDPASetAttr returned an unexpected error setting maxvqp to vdpa device: %v", err)
+	}
+}
+
+func TestVDPASetFeatures(t *testing.T) {
+	defer setupVDPATest(t, nl.VDPA_CMD_DEV_GET, nl.VDPA_CMD_DEV_CONFIG_GET, nl.VDPA_CMD_DEV_ATTR_SET)()
+	if err := createVDPATestDev(); err != nil {
+		t.Fatalf("failed to create VDPA device: %v", err)
+	}
+	// Default vdpa_sim_net features without VIRTIO_NET_F_CTRL_MAC_ADDR
+	err := VDPASetAttr(vdpaTestDeviceName, VDPANewDevParams{Features: 13019316265})
+	if !errors.Is(err, syscall.ENOTSUP) {
+		t.Fatalf("VDPASetAttr returned an unexpected error setting features to vdpa device: %v", err)
+	}
+}
+
 func TestSetGetBits(t *testing.T) {
 	features := SetBits(0, VIRTIO_NET_F_CSUM, VIRTIO_NET_F_MQ)
 	if !IsBitSet(features, VIRTIO_NET_F_CSUM) || !IsBitSet(features, VIRTIO_NET_F_MQ) {
@@ -236,6 +319,10 @@ func createVDPATestDev() error {
 	return VDPANewDev(vdpaTestDeviceName, "", vdpaSimMGMTDev, VDPANewDevParams{})
 }
 
+func createVDPATestDevWithParams(params VDPANewDevParams) error {
+	return VDPANewDev(vdpaTestDeviceName, "", vdpaSimMGMTDev, params)
+}
+
 func checkVDPAMGMTDev(t *testing.T, d *VDPAMGMTDev) {
 	if d == nil {
 		t.Fatal("VDPA MGMT dev is nil")