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]>
136 lines
2.8 KiB
ArmAsm
136 lines
2.8 KiB
ArmAsm
// 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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// +build amd64
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// test_util_amd64.s provides AMD64 test functions.
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#include "funcdata.h"
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#include "textflag.h"
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TEXT ·Getpid(SB),NOSPLIT|NOFRAME,$0
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NO_LOCAL_POINTERS
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MOVQ $39, AX // getpid
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SYSCALL
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RET
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// func AddrOfGetpid() uintptr
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TEXT ·AddrOfGetpid(SB), $0-8
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MOVQ $·Getpid(SB), AX
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MOVQ AX, ret+0(FP)
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RET
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TEXT ·touch(SB),NOSPLIT|NOFRAME,$0
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start:
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MOVQ 0(AX), BX // deref AX
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MOVQ $39, AX // getpid
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SYSCALL
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JMP start
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// func AddrOfTouch() uintptr
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TEXT ·AddrOfTouch(SB), $0-8
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MOVQ $·touch(SB), AX
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MOVQ AX, ret+0(FP)
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RET
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TEXT ·syscallLoop(SB),NOSPLIT|NOFRAME,$0
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start:
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SYSCALL
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JMP start
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// func AddrOfSyscallLoop() uintptr
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TEXT ·AddrOfSyscallLoop(SB), $0-8
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MOVQ $·syscallLoop(SB), AX
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MOVQ AX, ret+0(FP)
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RET
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TEXT ·spinLoop(SB),NOSPLIT|NOFRAME,$0
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start:
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JMP start
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// func AddrOfSpinLoop() uintptr
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TEXT ·AddrOfSpinLoop(SB), $0-8
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MOVQ $·spinLoop(SB), AX
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MOVQ AX, ret+0(FP)
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RET
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TEXT ·FloatingPointWorks(SB),NOSPLIT|NOFRAME,$0
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NO_LOCAL_POINTERS
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MOVQ $1, AX
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MOVQ AX, X0
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MOVQ $39, AX // getpid
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SYSCALL
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MOVQ X0, AX
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CMPQ AX, $1
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SETEQ ret+0(FP)
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RET
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#define TWIDDLE_REGS() \
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NOTQ R15; \
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NOTQ R14; \
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NOTQ R13; \
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NOTQ R12; \
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NOTQ BP; \
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NOTQ BX; \
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NOTQ R11; \
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NOTQ R10; \
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NOTQ R9; \
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NOTQ R8; \
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NOTQ AX; \
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NOTQ CX; \
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NOTQ DX; \
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NOTQ SI; \
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NOTQ DI; \
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NOTQ SP;
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TEXT ·twiddleRegsSyscall(SB),NOSPLIT|NOFRAME,$0
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TWIDDLE_REGS()
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SYSCALL
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RET // never reached
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// func AddrOfTwiddleRegsSyscall() uintptr
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TEXT ·AddrOfTwiddleRegsSyscall(SB), $0-8
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MOVQ $·twiddleRegsSyscall(SB), AX
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MOVQ AX, ret+0(FP)
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RET
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TEXT ·twiddleRegsFault(SB),NOSPLIT|NOFRAME,$0
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TWIDDLE_REGS()
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JMP AX // must fault
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RET // never reached
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// func AddrOfTwiddleRegsFault() uintptr
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TEXT ·AddrOfTwiddleRegsFault(SB), $0-8
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MOVQ $·twiddleRegsFault(SB), AX
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MOVQ AX, ret+0(FP)
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RET
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#define READ_FS() BYTE $0x64; BYTE $0x48; BYTE $0x8b; BYTE $0x00;
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#define READ_GS() BYTE $0x65; BYTE $0x48; BYTE $0x8b; BYTE $0x00;
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TEXT ·twiddleSegments(SB),NOSPLIT|NOFRAME,$0
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MOVQ $0x0, AX
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READ_GS()
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MOVQ AX, BX
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MOVQ $0x0, AX
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READ_FS()
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SYSCALL
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RET // never reached
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// func AddrOfTwiddleSegments() uintptr
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TEXT ·AddrOfTwiddleSegments(SB), $0-8
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MOVQ $·twiddleSegments(SB), AX
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MOVQ AX, ret+0(FP)
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RET
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