84 lines
2.3 KiB
Go
84 lines
2.3 KiB
Go
// Copyright 2018 Google LLC
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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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package kvm
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import (
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"fmt"
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"reflect"
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"syscall"
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"gvisor.googlesource.com/gvisor/pkg/sentry/arch"
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"gvisor.googlesource.com/gvisor/pkg/sentry/platform/safecopy"
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)
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// bluepill enters guest mode.
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func bluepill(*vCPU)
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// sighandler is the signal entry point.
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func sighandler()
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// dieTrampoline is the assembly trampoline. This calls dieHandler.
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//
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// This uses an architecture-specific calling convention, documented in
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// dieArchSetup and the assembly implementation for dieTrampoline.
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func dieTrampoline()
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var (
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// savedHandler is a pointer to the previous handler.
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//
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// This is called by bluepillHandler.
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savedHandler uintptr
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// dieTrampolineAddr is the address of dieTrampoline.
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dieTrampolineAddr uintptr
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)
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// dieHandler is called by dieTrampoline.
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//
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//go:nosplit
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func dieHandler(c *vCPU) {
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throw(c.dieMessage)
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}
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// die is called to set the vCPU up to panic.
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//
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// This loads vCPU state, and sets up a call for the trampoline.
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//
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//go:nosplit
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func (c *vCPU) die(context *arch.SignalContext64, msg string) {
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// Save the death message, which will be thrown.
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c.dieMessage = msg
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// Reload all registers to have an accurate stack trace when we return
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// to host mode. This means that the stack should be unwound correctly.
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var guestRegs userRegs
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if errno := c.getUserRegisters(&guestRegs); errno != 0 {
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throw(msg)
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}
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// Setup the trampoline.
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dieArchSetup(c, context, &guestRegs)
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}
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func init() {
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// Install the handler.
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if err := safecopy.ReplaceSignalHandler(syscall.SIGSEGV, reflect.ValueOf(sighandler).Pointer(), &savedHandler); err != nil {
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panic(fmt.Sprintf("Unable to set handler for signal %d: %v", syscall.SIGSEGV, err))
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}
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// Extract the address for the trampoline.
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dieTrampolineAddr = reflect.ValueOf(dieTrampoline).Pointer()
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}
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