Avoid importing platforms from many source files

PiperOrigin-RevId: 256494243

3 files changed, 49 insertions, 0 deletions

diff --git a/pkg/sentry/platform/kvm/BUILD b/pkg/sentry/platform/kvm/BUILD
index 9ccf77fdf..ad8b95744 100644
--- a/pkg/sentry/platform/kvm/BUILD
+++ b/pkg/sentry/platform/kvm/BUILD
@@ -14,6 +14,7 @@ go_library(
         "bluepill_fault.go",
         "bluepill_unsafe.go",
         "context.go",
+        "filters.go",
         "kvm.go",
         "kvm_amd64.go",
         "kvm_amd64_unsafe.go",
@@ -33,6 +34,7 @@ go_library(
         "//pkg/cpuid",
         "//pkg/log",
         "//pkg/procid",
+        "//pkg/seccomp",
         "//pkg/sentry/arch",
         "//pkg/sentry/platform",
         "//pkg/sentry/platform/interrupt",
diff --git a/pkg/sentry/platform/kvm/filters.go b/pkg/sentry/platform/kvm/filters.go
new file mode 100644
index 000000000..7d949f1dd
--- /dev/null
+++ b/pkg/sentry/platform/kvm/filters.go
@@ -0,0 +1,33 @@
+// Copyright 2019 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.
+
+package kvm
+
+import (
+	"syscall"
+
+	"gvisor.dev/gvisor/pkg/seccomp"
+)
+
+// SyscallFilters returns syscalls made exclusively by the KVM platform.
+func (*KVM) SyscallFilters() seccomp.SyscallRules {
+	return seccomp.SyscallRules{
+		syscall.SYS_ARCH_PRCTL:      {},
+		syscall.SYS_IOCTL:           {},
+		syscall.SYS_MMAP:            {},
+		syscall.SYS_RT_SIGSUSPEND:   {},
+		syscall.SYS_RT_SIGTIMEDWAIT: {},
+		0xffffffffffffffff:          {}, // KVM uses syscall -1 to transition to host.
+	}
+}
diff --git a/pkg/sentry/platform/kvm/kvm.go b/pkg/sentry/platform/kvm/kvm.go
index b49d7f3c4..ee4cd2f4d 100644
--- a/pkg/sentry/platform/kvm/kvm.go
+++ b/pkg/sentry/platform/kvm/kvm.go
@@ -141,3 +141,17 @@ func (k *KVM) NewContext() platform.Context {
 		machine: k.machine,
 	}
 }
+
+type constructor struct{}
+
+func (*constructor) New(f *os.File) (platform.Platform, error) {
+	return New(f)
+}
+
+func (*constructor) OpenDevice() (*os.File, error) {
+	return OpenDevice()
+}
+
+func init() {
+	platform.Register("kvm", &constructor{})
+}