57 lines
1.8 KiB
Go
57 lines
1.8 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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// +build amd64
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package kvm
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import (
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"unsafe"
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"gvisor.googlesource.com/gvisor/pkg/sentry/arch"
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"gvisor.googlesource.com/gvisor/pkg/sentry/platform/ring0"
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)
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// bluepillArchContext returns the arch-specific context.
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//
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//go:nosplit
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func bluepillArchContext(context unsafe.Pointer) *arch.SignalContext64 {
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return &((*arch.UContext64)(context).MContext)
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}
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// dieArchSetup initialies the state for dieTrampoline.
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//
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// The amd64 dieTrampoline requires the vCPU to be set in BX, and the last RIP
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// to be in AX. The trampoline then simulates a call to dieHandler from the
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// provided RIP.
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//
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//go:nosplit
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func dieArchSetup(c *vCPU, context *arch.SignalContext64, guestRegs *userRegs) {
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// If the vCPU is in user mode, we set the stack to the stored stack
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// value in the vCPU itself. We don't want to unwind the user stack.
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if guestRegs.RFLAGS&ring0.UserFlagsSet == ring0.UserFlagsSet {
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regs := c.CPU.Registers()
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context.Rax = regs.Rax
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context.Rsp = regs.Rsp
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context.Rbp = regs.Rbp
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} else {
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context.Rax = guestRegs.RIP
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context.Rsp = guestRegs.RSP
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context.Rbp = guestRegs.RBP
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context.Eflags = guestRegs.RFLAGS
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}
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context.Rbx = uint64(uintptr(unsafe.Pointer(c)))
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context.Rip = uint64(dieTrampolineAddr)
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}
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