Optimize kvm/physical_map.go on Arm platform

Signed-off-by: Bin Lu <bin.lu@arm.com>

4 files changed, 44 insertions, 11 deletions

diff --git a/pkg/sentry/platform/kvm/BUILD b/pkg/sentry/platform/kvm/BUILD
index fe979dccf..2046df525 100644
--- a/pkg/sentry/platform/kvm/BUILD
+++ b/pkg/sentry/platform/kvm/BUILD
@@ -24,6 +24,8 @@ go_library(
         "machine_amd64_unsafe.go",
         "machine_unsafe.go",
         "physical_map.go",
+        "physical_map_amd64.go",
+        "physical_map_arm64.go",
         "virtual_map.go",
     ],
     importpath = "gvisor.dev/gvisor/pkg/sentry/platform/kvm",
diff --git a/pkg/sentry/platform/kvm/physical_map.go b/pkg/sentry/platform/kvm/physical_map.go
index 586e91bb2..91de5dab1 100644
--- a/pkg/sentry/platform/kvm/physical_map.go
+++ b/pkg/sentry/platform/kvm/physical_map.go
@@ -24,15 +24,6 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/usermem"
 )
 
-const (
-	// reservedMemory is a chunk of physical memory reserved starting at
-	// physical address zero. There are some special pages in this region,
-	// so we just call the whole thing off.
-	//
-	// Other architectures may define this to be zero.
-	reservedMemory = 0x100000000
-)
-
 type region struct {
 	virtual uintptr
 	length  uintptr
@@ -59,8 +50,7 @@ func fillAddressSpace() (excludedRegions []region) {
 	// We can cut vSize in half, because the kernel will be using the top
 	// half and we ignore it while constructing mappings. It's as if we've
 	// already excluded half the possible addresses.
-	vSize := uintptr(1) << ring0.VirtualAddressBits()
-	vSize = vSize >> 1
+	vSize := ring0.UserspaceSize
 
 	// We exclude reservedMemory below from our physical memory size, so it
 	// needs to be dropped here as well. Otherwise, we could end up with
diff --git a/pkg/sentry/platform/kvm/physical_map_amd64.go b/pkg/sentry/platform/kvm/physical_map_amd64.go
new file mode 100644
index 000000000..c5adfb577
--- /dev/null
+++ b/pkg/sentry/platform/kvm/physical_map_amd64.go
@@ -0,0 +1,22 @@
+// 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
+
+const (
+	// reservedMemory is a chunk of physical memory reserved starting at
+	// physical address zero. There are some special pages in this region,
+	// so we just call the whole thing off.
+	reservedMemory = 0x100000000
+)
diff --git a/pkg/sentry/platform/kvm/physical_map_arm64.go b/pkg/sentry/platform/kvm/physical_map_arm64.go
new file mode 100644
index 000000000..4d8561453
--- /dev/null
+++ b/pkg/sentry/platform/kvm/physical_map_arm64.go
@@ -0,0 +1,19 @@
+// 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
+
+const (
+	reservedMemory = 0
+)