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https://github.com/hanzoai/visor.git
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Andrei VaginandgVisor bot
e1cc03b1f8
The core of this change is to add a sanity check in archExitSanityCheck that triggers a panic if rip, rsp, or rbp point to kernel addresses upon a KVM exit on amd64. This is intended to help debug faults on kernel addresses. PiperOrigin-RevId: 815937504
148 lines
3.5 KiB
Go
148 lines
3.5 KiB
Go
// Copyright 2019 The gVisor Authors.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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//go:build arm64
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// +build arm64
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package kvm
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import (
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"fmt"
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"golang.org/x/sys/unix"
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"gvisor.dev/gvisor/pkg/ring0"
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"gvisor.dev/gvisor/pkg/sentry/arch"
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"gvisor.dev/gvisor/pkg/sighandling"
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)
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var (
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// The action for bluepillSignal is changed by sigaction().
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bluepillSignal = unix.SIGILL
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)
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// bluepill enters guest mode.
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//
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//go:nosplit
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func bluepill(c *vCPU)
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// getTLS returns the value of TPIDR_EL0 register.
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//
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//go:nosplit
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func getTLS() (value uint64)
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// setTLS writes the TPIDR_EL0 value.
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//
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//go:nosplit
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func setTLS(value uint64)
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// bluepillArchEnter is called during bluepillEnter.
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//
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//go:nosplit
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func bluepillArchEnter(context *arch.SignalContext64) (c *vCPU) {
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c = vCPUPtr(uintptr(context.Regs[8]))
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regs := c.CPU.Registers()
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regs.Regs = context.Regs
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regs.Sp = context.Sp
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regs.Pc = context.Pc
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regs.Pstate = context.Pstate
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regs.Pstate &^= uint64(ring0.PsrFlagsClear)
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regs.Pstate |= ring0.KernelFlagsSet
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regs.TPIDR_EL0 = getTLS()
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return
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}
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// bluepillArchExit is called during bluepillEnter.
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//
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//go:nosplit
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func bluepillArchExit(c *vCPU, context *arch.SignalContext64) {
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regs := c.CPU.Registers()
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context.Regs = regs.Regs
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context.Sp = regs.Sp
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context.Pc = regs.Pc
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context.Pstate = regs.Pstate
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context.Pstate &^= uint64(ring0.PsrFlagsClear)
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context.Pstate |= ring0.UserFlagsSet
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setTLS(regs.TPIDR_EL0)
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lazyVfp := c.GetLazyVFP()
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if lazyVfp != 0 {
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fpsimd := fpsimdPtr(c.FloatingPointState().BytePointer()) // escapes: no
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context.Fpsimd64.Fpsr = fpsimd.Fpsr
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context.Fpsimd64.Fpcr = fpsimd.Fpcr
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context.Fpsimd64.Vregs = fpsimd.Vregs
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}
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}
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// KernelSyscall handles kernel syscalls.
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//
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// +checkescape:all
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//
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//go:nosplit
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func (c *vCPU) KernelSyscall() {
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regs := c.Registers()
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if regs.Regs[8] != ^uint64(0) {
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regs.Pc -= 4 // Rewind.
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}
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fpDisableTrap := ring0.CPACREL1()
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if fpDisableTrap != 0 {
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fpsimd := fpsimdPtr(c.FloatingPointState().BytePointer()) // escapes: no
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fpcr := ring0.GetFPCR()
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fpsr := ring0.GetFPSR()
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fpsimd.Fpcr = uint32(fpcr)
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fpsimd.Fpsr = uint32(fpsr)
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ring0.SaveVRegs(c.FloatingPointState().BytePointer()) // escapes: no
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}
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ring0.Halt()
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}
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// KernelException handles kernel exceptions.
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//
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// +checkescape:all
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//
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//go:nosplit
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func (c *vCPU) KernelException(vector ring0.Vector) {
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regs := c.Registers()
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if vector == ring0.Vector(bounce) {
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regs.Pc = 0
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}
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fpDisableTrap := ring0.CPACREL1()
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if fpDisableTrap != 0 {
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fpsimd := fpsimdPtr(c.FloatingPointState().BytePointer()) // escapes: no
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fpcr := ring0.GetFPCR()
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fpsr := ring0.GetFPSR()
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fpsimd.Fpcr = uint32(fpcr)
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fpsimd.Fpsr = uint32(fpsr)
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ring0.SaveVRegs(c.FloatingPointState().BytePointer()) // escapes: no
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}
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ring0.Halt()
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}
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func currentEL() uint64
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func inKernelMode() bool {
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return currentEL() == 1
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}
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func init() {
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// Install the handler.
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if err := sighandling.ReplaceSignalHandler(bluepillSignal, addrOfSighandler(), &savedHandler); err != nil {
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panic(fmt.Sprintf("Unable to set handler for signal %d: %v", bluepillSignal, err))
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}
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}
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