mirror of
https://github.com/hanzoai/visor.git
synced 2026-09-24 17:04:14 +00:00
Tianyu Zhou
fc1afc9de5
SlimVM is a lightweight VMX-based platform for gVisor that accelerates sentry system calls by eliminating unnecessary user/kernel context switches. In a traditional gVisor + KVM setup, every guest syscall triggers a full VM exit to userspace, then re-enters the kernel via a regular syscall: gr0 -> hr0 (vm_exit) -> hr3 (ioctl return) -> hr0 (re-invoke syscall) SlimVM eliminates this overhead. When the guest executes a VMCALL, the VM exits into VMX root mode where SlimVM directly invokes the host kernel's syscall handler, then immediately resumes the guest: gr0 -> hr0 (vmcall + direct function call) SlimVM requires a companion kernel module that provides the /dev/slimvm device interface. See https://github.com/antgroup/slimvm for the kernel module and full documentation. A sentry->host getpid microbenchmark (Xeon 6982P-C, host kernel 5.10.134) shows the effect: │ ns/op │ vs base │ base 82.5 1.0x slimvm 420.9 5.1x kvm 3566.1 43.2x slimvm is ~8.5x faster than the kvm platform on this path. See the issue for details. Updates: https://github.com/google/gvisor/issues/13330 Co-developed-by: Chenggang <[email protected]> Co-developed-by: Robin Luk <[email protected]> Co-developed-by: Tiwei Bie <[email protected]> Co-developed-by: Jianfeng Tan <[email protected]> Co-developed-by: liushi.ls <[email protected]> Co-developed-by: Yong He <[email protected]> Co-developed-by: Aaron Lu <[email protected]> Co-developed-by: chris.zn <[email protected]> Co-developed-by: Lai Jiangshan <[email protected]> Co-developed-by: Lingfu <[email protected]> Co-developed-by: Min Le <[email protected]> Co-developed-by: Quan Xu <[email protected]> Co-developed-by: Zhang Haoyu <[email protected]> Co-developed-by: Dawei Shen <[email protected]> Signed-off-by: Tianyu Zhou <[email protected]>
91 lines
2.7 KiB
Go
91 lines
2.7 KiB
Go
// Copyright 2026 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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// Package testutil provides common assembly stubs for testing.
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package testutil
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import (
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"fmt"
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"strings"
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)
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// Getpid executes a trivial system call.
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func Getpid()
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// AddrOfGetpid returns the address of Getpid.
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//
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// In Go 1.17+, Go references to assembly functions resolve to an ABIInternal
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// wrapper function rather than the function itself. We must reference from
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// assembly to get the ABI0 (i.e., primary) address.
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func AddrOfGetpid() uintptr
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// AddrOfTouch returns the address of a function that touches the value in the
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// first register.
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func AddrOfTouch() uintptr
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func touch()
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// AddrOfSyscallLoop returns the address of a function that executes a syscall
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// and loops.
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func AddrOfSyscallLoop() uintptr
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func syscallLoop()
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// AddrOfSpinLoop returns the address of a function that spins on the CPU.
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func AddrOfSpinLoop() uintptr
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func spinLoop()
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// AddrOfHaltLoop returns the address of a function that immediately halts and
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// loops.
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func AddrOfHaltLoop() uintptr
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func haltLoop()
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// AddrOfTwiddleRegsFault returns the address of a function that twiddles
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// registers then faults.
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func AddrOfTwiddleRegsFault() uintptr
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func twiddleRegsFault()
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// AddrOfTwiddleRegsSyscall returns the address of a function that twiddles
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// registers then executes a syscall.
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func AddrOfTwiddleRegsSyscall() uintptr
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func twiddleRegsSyscall()
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// FloatingPointWorks is a floating point test.
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//
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// It returns true or false.
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func FloatingPointWorks() bool
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// RegisterMismatchError is used for checking registers.
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type RegisterMismatchError []string
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// Error returns a human-readable error.
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func (r RegisterMismatchError) Error() string {
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return strings.Join([]string(r), ";")
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}
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// addRegisterMisatch allows simple chaining of register mismatches.
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func addRegisterMismatch(err error, reg string, got, expected any) error {
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errStr := fmt.Sprintf("%s got %08x, expected %08x", reg, got, expected)
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switch r := err.(type) {
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case nil:
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// Return a new register mismatch.
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return RegisterMismatchError{errStr}
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case RegisterMismatchError:
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// Append the error.
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r = append(r, errStr)
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return r
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default:
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// Leave as is.
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return err
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}
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}
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