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]>
77 lines
1.9 KiB
Go
77 lines
1.9 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 slimvm
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import (
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"fmt"
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"gvisor.dev/gvisor/pkg/ring0/pagetables"
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)
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type allocator struct {
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base *pagetables.RuntimeAllocator
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}
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// newAllocator is used to define the allocator.
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func newAllocator() allocator {
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return allocator{
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base: pagetables.NewRuntimeAllocator(),
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}
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}
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// NewPTEs implements pagetables.Allocator.NewPTEs.
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//
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//go:nosplit
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func (a allocator) NewPTEs() *pagetables.PTEs {
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return a.base.NewPTEs()
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}
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// PhysicalFor returns the physical address for a set of PTEs.
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//
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//go:nosplit
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func (a allocator) PhysicalFor(ptes *pagetables.PTEs) uintptr {
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virtual := a.base.PhysicalFor(ptes)
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physical, _, ok := translateToPhysical(virtual)
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if !ok {
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panic(fmt.Sprintf("PhysicalFor failed for %p", ptes))
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}
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return physical
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}
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// LookupPTEs implements pagetables.Allocator.LookupPTEs.
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//
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//go:nosplit
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func (a allocator) LookupPTEs(physical uintptr) *pagetables.PTEs {
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virtualStart, physicalStart, _, ok := calculateBluepillFault(physical)
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if !ok {
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panic(fmt.Sprintf("LookupPTEs failed for 0x%x", physical))
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}
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return a.base.LookupPTEs(virtualStart + (physical - physicalStart))
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}
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// FreePTEs implements pagetables.Allocator.FreePTEs.
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//
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//go:nosplit
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func (a allocator) FreePTEs(ptes *pagetables.PTEs) {
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a.base.FreePTEs(ptes)
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}
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// Recycle implements pagetables.Allocator.Recycle.
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//
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//go:nosplit
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func (a allocator) Recycle() {
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a.base.Recycle()
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}
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