Adding LinuxKernelDirect boot support

functional/lcow_test.go

@@ -66,24 +66,46 @@ func testLCOWUVMNoSCSISingleVPMem(t *testing.T, opts *uvm.UVMOptions, expected s
 // TestLCOWTimeUVMStartVHD starts/terminates a utility VM booting from VPMem-
 // attached root filesystem a number of times.
 func TestLCOWTimeUVMStartVHD(t *testing.T) {
-	testLCOWTimeUVMStart(t, uvm.PreferredRootFSTypeVHD)
+	testutilities.RequiresBuild(t, osversion.RS5)
+
+	testLCOWTimeUVMStart(t, false, uvm.PreferredRootFSTypeVHD)
+}
+
+// TestLCOWUVMStart_KernelDirect_VHD starts/terminates a utility VM booting from
+// VPMem- attached root filesystem a number of times starting from the Linux
+// Kernel directly and skipping EFI.
+func TestLCOWUVMStart_KernelDirect_VHD(t *testing.T) {
+	testutilities.RequiresBuild(t, 18286)
+
+	testLCOWTimeUVMStart(t, true, uvm.PreferredRootFSTypeVHD)
 }
 
 // TestLCOWTimeUVMStartInitRD starts/terminates a utility VM booting from initrd-
 // attached root file system a number of times.
 func TestLCOWTimeUVMStartInitRD(t *testing.T) {
-	testLCOWTimeUVMStart(t, uvm.PreferredRootFSTypeInitRd)
+	testutilities.RequiresBuild(t, osversion.RS5)
+
+	testLCOWTimeUVMStart(t, false, uvm.PreferredRootFSTypeInitRd)
 }
 
-func testLCOWTimeUVMStart(t *testing.T, rfsType uvm.PreferredRootFSType) {
-	testutilities.RequiresBuild(t, osversion.RS5)
+// TestLCOWUVMStart_KernelDirect_InitRd starts/terminates a utility VM booting
+// from initrd- attached root file system a number of times starting from the
+// Linux Kernel directly and skipping EFI.
+func TestLCOWUVMStart_KernelDirect_InitRd(t *testing.T) {
+	testutilities.RequiresBuild(t, 18286)
+
+	testLCOWTimeUVMStart(t, true, uvm.PreferredRootFSTypeInitRd)
+}
+
+func testLCOWTimeUVMStart(t *testing.T, kernelDirect bool, rfsType uvm.PreferredRootFSType) {
 	var vpmemCount uint32 = 32
 	for i := 0; i < 3; i++ {
 		opts := &uvm.UVMOptions{
 			OperatingSystem:     "linux",
 			ID:                  "uvm",
 			VPMemDeviceCount:    &vpmemCount,
 			PreferredRootFSType: &rfsType,
+			KernelDirect:        kernelDirect,
 		}
 		lcowUVM := testutilities.CreateLCOWUVMFromOpts(t, opts)
 		lcowUVM.Close()

internal/schema2/chipset.go

@@ -10,7 +10,6 @@
 package hcsschema
 
 type Chipset struct {
-
 	Uefi *Uefi `json:"Uefi,omitempty"`
 
 	IsNumLockDisabled bool `json:"IsNumLockDisabled,omitempty"`
@@ -22,4 +21,7 @@ type Chipset struct {
 	ChassisAssetTag string `json:"ChassisAssetTag,omitempty"`
 
 	UseUtc bool `json:"UseUtc,omitempty"`
+
+	// LinuxKernelDirect - Added in v2.2 Builds >=181117
+	LinuxKernelDirect *LinuxKernelDirect `json:"LinuxKernelDirect,omitempty"`
 }

internal/schema2/linux_kernel_direct.go

@@ -0,0 +1,18 @@
+/*
+ * HCS API
+ *
+ * No description provided (generated by Swagger Codegen https://github.com/swagger-api/swagger-codegen)
+ *
+ * API version: 2.2
+ * Generated by: Swagger Codegen (https://github.com/swagger-api/swagger-codegen.git)
+ */
+
+package hcsschema
+
+type LinuxKernelDirect struct {
+	KernelFilePath string `json:"KernelFilePath,omitempty"`
+
+	InitRdPath string `json:"InitRdPath,omitempty"`
+
+	KernelCmdLine string `json:"KernelCmdLine,omitempty"`
+}

internal/uvm/create.go

@@ -17,6 +17,7 @@ import (
 	"github.com/Microsoft/hcsshim/internal/uvmfolder"
 	"github.com/Microsoft/hcsshim/internal/wclayer"
 	"github.com/Microsoft/hcsshim/internal/wcow"
+	"github.com/Microsoft/hcsshim/osversion"
 	"github.com/linuxkit/virtsock/pkg/hvsock"
 	specs "github.com/opencontainers/runtime-spec/specs-go"
 	"github.com/sirupsen/logrus"
@@ -46,6 +47,7 @@ type UVMOptions struct {
 	// LCOW specific parameters
 	BootFilesPath         string  // Folder in which kernel and root file system reside. Defaults to \Program Files\Linux Containers
 	KernelFile            string  // Filename under BootFilesPath for the kernel. Defaults to `kernel`
+	KernelDirect          bool    // Skip UEFI and boot directly to `kernel`
 	RootFSFile            string  // Filename under BootFilesPath for the UVMs root file system. Defaults are `initrd.img` or `rootfs.vhd`.
 	KernelBootOptions     string  // Additional boot options for the kernel
 	EnableGraphicsConsole bool    // If true, enable a graphics console for the utility VM
@@ -179,6 +181,9 @@ func Create(opts *UVMOptions) (_ *UtilityVM, err error) {
 				uvm.vpmemMaxSizeBytes = *opts.VPMemSizeBytes
 			}
 		}
+		if opts.KernelDirect && osversion.Get().Build < 18286 {
+			return nil, fmt.Errorf("KernelDirectBoot is not support on builds older than 18286")
+		}
 
 		scsi["0"] = hcsschema.Scsi{Attachments: attachments}
 		uvm.scsiControllerCount = 1
@@ -333,19 +338,21 @@ func Create(opts *UVMOptions) (_ *UtilityVM, err error) {
 		vmDebugging := false
 		vm.GuestConnection.UseVsock = true
 		vm.GuestConnection.UseConnectedSuspend = true
-		vm.Devices.VirtualSmb = &hcsschema.VirtualSmb{
-			Shares: []hcsschema.VirtualSmbShare{
-				{
-					Name: "os",
-					Path: opts.BootFilesPath,
-					Options: &hcsschema.VirtualSmbShareOptions{
-						ReadOnly:            true,
-						TakeBackupPrivilege: true,
-						CacheIo:             true,
-						ShareRead:           true,
+		if !opts.KernelDirect {
+			vm.Devices.VirtualSmb = &hcsschema.VirtualSmb{
+				Shares: []hcsschema.VirtualSmbShare{
+					{
+						Name: "os",
+						Path: opts.BootFilesPath,
+						Options: &hcsschema.VirtualSmbShareOptions{
+							ReadOnly:            true,
+							TakeBackupPrivilege: true,
+							CacheIo:             true,
+							ShareRead:           true,
+						},
 					},
 				},
-			},
+			}
 		}
 
 		if uvm.vpmemMaxCount > 0 {
@@ -355,8 +362,13 @@ func Create(opts *UVMOptions) (_ *UtilityVM, err error) {
 			}
 		}
 
-		kernelArgs := "initrd=/" + opts.RootFSFile
-		if actualRootFSType == PreferredRootFSTypeVHD {
+		var kernelArgs string
+		switch actualRootFSType {
+		case PreferredRootFSTypeInitRd:
+			if !opts.KernelDirect {
+				kernelArgs = "initrd=/" + opts.RootFSFile
+			}
+		case PreferredRootFSTypeVHD:
 			kernelArgs = "root=/dev/pmem0 init=/init"
 		}
 
@@ -428,10 +440,22 @@ func Create(opts *UVMOptions) (_ *UtilityVM, err error) {
 		}
 
 		kernelArgs += ` pci=off -- ` + initArgs
-		vm.Chipset.Uefi.BootThis = &hcsschema.UefiBootEntry{
-			DevicePath:   `\` + opts.KernelFile,
-			DeviceType:   "VmbFs",
-			OptionalData: kernelArgs,
+
+		if !opts.KernelDirect {
+			vm.Chipset.Uefi.BootThis = &hcsschema.UefiBootEntry{
+				DevicePath:   `\` + opts.KernelFile,
+				DeviceType:   "VmbFs",
+				OptionalData: kernelArgs,
+			}
+		} else {
+			vm.Chipset.Uefi = nil
+			vm.Chipset.LinuxKernelDirect = &hcsschema.LinuxKernelDirect{
+				KernelFilePath: filepath.Join(opts.BootFilesPath, opts.KernelFile),
+				KernelCmdLine:  kernelArgs,
+			}
+			if actualRootFSType == PreferredRootFSTypeInitRd {
+				vm.Chipset.LinuxKernelDirect.InitRdPath = filepath.Join(opts.BootFilesPath, opts.RootFSFile)
+			}
 		}
 	}