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]>
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