Merge 216da0b7 (automated)

1 files changed, 77 insertions, 0 deletions

diff --git a/pkg/sentry/platform/kvm/kvm_amd64_unsafe.go b/pkg/sentry/platform/kvm/kvm_amd64_unsafe.go
new file mode 100644
index 000000000..46c4b9113
--- /dev/null
+++ b/pkg/sentry/platform/kvm/kvm_amd64_unsafe.go
@@ -0,0 +1,77 @@
+// Copyright 2018 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.
+
+// +build amd64
+
+package kvm
+
+import (
+	"fmt"
+	"syscall"
+	"unsafe"
+)
+
+var (
+	runDataSize    int
+	hasGuestPCID   bool
+	cpuidSupported = cpuidEntries{nr: _KVM_NR_CPUID_ENTRIES}
+)
+
+func updateSystemValues(fd int) error {
+	// Extract the mmap size.
+	sz, _, errno := syscall.RawSyscall(syscall.SYS_IOCTL, uintptr(fd), _KVM_GET_VCPU_MMAP_SIZE, 0)
+	if errno != 0 {
+		return fmt.Errorf("getting VCPU mmap size: %v", errno)
+	}
+
+	// Save the data.
+	runDataSize = int(sz)
+
+	// Must do the dance to figure out the number of entries.
+	_, _, errno = syscall.RawSyscall(
+		syscall.SYS_IOCTL,
+		uintptr(fd),
+		_KVM_GET_SUPPORTED_CPUID,
+		uintptr(unsafe.Pointer(&cpuidSupported)))
+	if errno != 0 && errno != syscall.ENOMEM {
+		// Some other error occurred.
+		return fmt.Errorf("getting supported CPUID: %v", errno)
+	}
+
+	// The number should now be correct.
+	_, _, errno = syscall.RawSyscall(
+		syscall.SYS_IOCTL,
+		uintptr(fd),
+		_KVM_GET_SUPPORTED_CPUID,
+		uintptr(unsafe.Pointer(&cpuidSupported)))
+	if errno != 0 {
+		// Didn't work with the right number.
+		return fmt.Errorf("getting supported CPUID (2nd attempt): %v", errno)
+	}
+
+	// Calculate whether guestPCID is supported.
+	//
+	// FIXME(ascannell): These should go through the much more pleasant
+	// cpuid package interfaces, once a way to accept raw kvm CPUID entries
+	// is plumbed (or some rough equivalent).
+	for i := 0; i < int(cpuidSupported.nr); i++ {
+		entry := cpuidSupported.entries[i]
+		if entry.function == 1 && entry.index == 0 && entry.ecx&(1<<17) != 0 {
+			hasGuestPCID = true // Found matching PCID in guest feature set.
+		}
+	}
+
+	// Success.
+	return nil
+}