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// 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.
// +build arm64
package kvm
import (
"syscall"
"unsafe"
"gvisor.dev/gvisor/pkg/ring0"
"gvisor.dev/gvisor/pkg/sentry/arch"
)
// fpsimdPtr returns a fpsimd64 for the given address.
//
//go:nosplit
func fpsimdPtr(addr *byte) *arch.FpsimdContext {
return (*arch.FpsimdContext)(unsafe.Pointer(addr))
}
// dieArchSetup initialies the state for dieTrampoline.
//
// The arm64 dieTrampoline requires the vCPU to be set in R1, and the last PC
// to be in R0. The trampoline then simulates a call to dieHandler from the
// provided PC.
//
//go:nosplit
func dieArchSetup(c *vCPU, context *arch.SignalContext64, guestRegs *userRegs) {
// If the vCPU is in user mode, we set the stack to the stored stack
// value in the vCPU itself. We don't want to unwind the user stack.
if guestRegs.Regs.Pstate&ring0.PsrModeMask == ring0.UserFlagsSet {
regs := c.CPU.Registers()
context.Regs[0] = regs.Regs[0]
context.Sp = regs.Sp
context.Regs[29] = regs.Regs[29] // stack base address
} else {
context.Regs[0] = guestRegs.Regs.Pc
context.Sp = guestRegs.Regs.Sp
context.Regs[29] = guestRegs.Regs.Regs[29]
context.Pstate = guestRegs.Regs.Pstate
}
context.Regs[1] = uint64(uintptr(unsafe.Pointer(c)))
context.Pc = uint64(dieTrampolineAddr)
}
// bluepillArchFpContext returns the arch-specific fpsimd context.
//
//go:nosplit
func bluepillArchFpContext(context unsafe.Pointer) *arch.FpsimdContext {
return &((*arch.SignalContext64)(context).Fpsimd64)
}
// getHypercallID returns hypercall ID.
//
// On Arm64, the MMIO address should be 64-bit aligned.
//
//go:nosplit
func getHypercallID(addr uintptr) int {
if addr < arm64HypercallMMIOBase || addr >= (arm64HypercallMMIOBase+_AARCH64_HYPERCALL_MMIO_SIZE) {
return _KVM_HYPERCALL_MAX
} else {
return int(((addr) - arm64HypercallMMIOBase) >> 3)
}
}
// bluepillStopGuest is reponsible for injecting sError.
//
//go:nosplit
func bluepillStopGuest(c *vCPU) {
if _, _, errno := syscall.RawSyscall( // escapes: no.
syscall.SYS_IOCTL,
uintptr(c.fd),
_KVM_SET_VCPU_EVENTS,
uintptr(unsafe.Pointer(&vcpuSErrBounce))); errno != 0 {
throw("bounce sErr injection failed")
}
}
// bluepillSigBus is reponsible for injecting sError to trigger sigbus.
//
//go:nosplit
func bluepillSigBus(c *vCPU) {
// Host must support ARM64_HAS_RAS_EXTN.
if _, _, errno := syscall.RawSyscall( // escapes: no.
syscall.SYS_IOCTL,
uintptr(c.fd),
_KVM_SET_VCPU_EVENTS,
uintptr(unsafe.Pointer(&vcpuSErrNMI))); errno != 0 {
if errno == syscall.EINVAL {
throw("No ARM64_HAS_RAS_EXTN feature in host.")
}
throw("nmi sErr injection failed")
}
}
// bluepillExtDabt is reponsible for injecting external data abort.
//
//go:nosplit
func bluepillExtDabt(c *vCPU) {
if _, _, errno := syscall.RawSyscall( // escapes: no.
syscall.SYS_IOCTL,
uintptr(c.fd),
_KVM_SET_VCPU_EVENTS,
uintptr(unsafe.Pointer(&vcpuExtDabt))); errno != 0 {
throw("ext_dabt injection failed")
}
}
// bluepillHandleEnosys is reponsible for handling enosys error.
//
//go:nosplit
func bluepillHandleEnosys(c *vCPU) {
bluepillExtDabt(c)
}
// bluepillReadyStopGuest checks whether the current vCPU is ready for sError injection.
//
//go:nosplit
func bluepillReadyStopGuest(c *vCPU) bool {
return true
}
// bluepillArchHandleExit checks architecture specific exitcode.
//
//go:nosplit
func bluepillArchHandleExit(c *vCPU, context unsafe.Pointer) {
switch c.runData.exitReason {
case _KVM_EXIT_ARM_NISV:
bluepillExtDabt(c)
default:
c.die(bluepillArchContext(context), "unknown")
}
}
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