Internal change

PiperOrigin-RevId: 727079732

pkg/sentry/platform/kvm/BUILD

@@ -41,6 +41,7 @@ go_library(
         "bluepill_arm64_unsafe.go",
         "bluepill_fault.go",
         "bluepill_unsafe.go",
+        "config.go",
         "context.go",
         "filters.go",
         "filters_amd64.go",

pkg/sentry/platform/kvm/config.go

@@ -0,0 +1,23 @@
+// Copyright 2025 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//go:build !false
+// +build !false
+
+package kvm
+
+// Config sets configuration options for each platform instance.
+type Config struct{}
+
+func (*machine) applyConfig(config *Config) error { return nil }

pkg/sentry/platform/kvm/kvm.go

@@ -92,7 +92,7 @@ func OpenDevice(devicePath string) (*fd.FD, error) {
 }
 
 // New returns a new KVM-based implementation of the platform interface.
-func New(deviceFile *fd.FD) (*KVM, error) {
+func New(deviceFile *fd.FD, config Config) (*KVM, error) {
 	fd := deviceFile.FD()
 
 	// Ensure global initialization is done.
@@ -122,7 +122,7 @@ func New(deviceFile *fd.FD) (*KVM, error) {
 	deviceFile.Close()
 
 	// Create a VM context.
-	machine, err := newMachine(int(vm))
+	machine, err := newMachine(int(vm), &config)
 	if err != nil {
 		return nil, err
 	}
@@ -185,7 +185,7 @@ func (k *KVM) NewContext(pkgcontext.Context) platform.Context {
 type constructor struct{}
 
 func (*constructor) New(f *fd.FD) (platform.Platform, error) {
-	return New(f)
+	return New(f, Config{})
 }
 
 func (*constructor) OpenDevice(devicePath string) (*fd.FD, error) {

pkg/sentry/platform/kvm/kvm_const.go

@@ -42,6 +42,7 @@ const (
 	KVM_GET_VCPU_EVENTS        = 0x8040ae9f
 	KVM_SET_VCPU_EVENTS        = 0x4040aea0
 	KVM_SET_DEVICE_ATTR        = 0x4018aee1
+	KVM_ENABLE_CAP             = 0x4068aea3
 )
 
 // KVM exit reasons.

pkg/sentry/platform/kvm/kvm_test.go

@@ -48,7 +48,7 @@ func kvmTest(t testHarness, setup func(*KVM), fn func(*vCPU) bool) {
 	if err != nil {
 		t.Fatalf("error opening device file: %v", err)
 	}
-	k, err := New(deviceFile)
+	k, err := New(deviceFile, Config{})
 	if err != nil {
 		t.Fatalf("error creating KVM instance: %v", err)
 	}

pkg/sentry/platform/kvm/machine.go

@@ -267,11 +267,15 @@ func (m *machine) createVCPU(id int) *vCPU {
 var forceMappingEntireAddressSpace = false
 
 // newMachine returns a new VM context.
-func newMachine(vm int) (*machine, error) {
+func newMachine(vm int, config *Config) (*machine, error) {
 	// Create the machine.
 	m := &machine{fd: vm}
 	m.available.L = &m.mu
 
+	if err := m.applyConfig(config); err != nil {
+		panic(fmt.Sprintf("error setting config parameters: %s", err))
+	}
+
 	// Pull the maximum vCPUs.
 	m.getMaxVCPU()
 	log.Debugf("The maximum number of vCPUs is %d.", m.maxVCPUs)
@@ -876,3 +880,10 @@ func seccompMmapRules(m *machine) {
 	m.machinePoolIndex = i
 	machinePoolMu.Unlock()
 }
+
+type kvmEnableCap struct {
+	capability uint32
+	flags      uint32
+	args       [4]uint64
+	pad        [64]uint8
+}