From 1336af78d5dc2a6bc54d22ed45f4dd4793c2f964 Mon Sep 17 00:00:00 2001
From: Jamie Liu <jamieliu@google.com>
Date: Tue, 6 Oct 2020 13:53:26 -0700
Subject: Implement membarrier(2) commands other than *_SYNC_CORE.

Updates #267

PiperOrigin-RevId: 335713923
---
 pkg/sentry/platform/kvm/BUILD            |  1 +
 pkg/sentry/platform/kvm/filters_amd64.go | 13 +++++++++++--
 pkg/sentry/platform/kvm/filters_arm64.go | 11 ++++++++++-
 pkg/sentry/platform/kvm/kvm.go           |  3 +++
 4 files changed, 25 insertions(+), 3 deletions(-)

(limited to 'pkg/sentry/platform/kvm')

diff --git a/pkg/sentry/platform/kvm/BUILD b/pkg/sentry/platform/kvm/BUILD
index 323837fb1..9fe23c417 100644
--- a/pkg/sentry/platform/kvm/BUILD
+++ b/pkg/sentry/platform/kvm/BUILD
@@ -56,6 +56,7 @@ go_library(
         "//pkg/sentry/time",
         "//pkg/sync",
         "//pkg/usermem",
+        "@org_golang_x_sys//unix:go_default_library",
     ],
 )
 
diff --git a/pkg/sentry/platform/kvm/filters_amd64.go b/pkg/sentry/platform/kvm/filters_amd64.go
index 7d949f1dd..d3d216aa5 100644
--- a/pkg/sentry/platform/kvm/filters_amd64.go
+++ b/pkg/sentry/platform/kvm/filters_amd64.go
@@ -17,14 +17,23 @@ package kvm
 import (
 	"syscall"
 
+	"golang.org/x/sys/unix"
+
+	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/seccomp"
 )
 
 // SyscallFilters returns syscalls made exclusively by the KVM platform.
 func (*KVM) SyscallFilters() seccomp.SyscallRules {
 	return seccomp.SyscallRules{
-		syscall.SYS_ARCH_PRCTL:      {},
-		syscall.SYS_IOCTL:           {},
+		syscall.SYS_ARCH_PRCTL: {},
+		syscall.SYS_IOCTL:      {},
+		unix.SYS_MEMBARRIER: []seccomp.Rule{
+			{
+				seccomp.EqualTo(linux.MEMBARRIER_CMD_PRIVATE_EXPEDITED),
+				seccomp.EqualTo(0),
+			},
+		},
 		syscall.SYS_MMAP:            {},
 		syscall.SYS_RT_SIGSUSPEND:   {},
 		syscall.SYS_RT_SIGTIMEDWAIT: {},
diff --git a/pkg/sentry/platform/kvm/filters_arm64.go b/pkg/sentry/platform/kvm/filters_arm64.go
index 9245d07c2..21abc2a3d 100644
--- a/pkg/sentry/platform/kvm/filters_arm64.go
+++ b/pkg/sentry/platform/kvm/filters_arm64.go
@@ -17,13 +17,22 @@ package kvm
 import (
 	"syscall"
 
+	"golang.org/x/sys/unix"
+
+	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/seccomp"
 )
 
 // SyscallFilters returns syscalls made exclusively by the KVM platform.
 func (*KVM) SyscallFilters() seccomp.SyscallRules {
 	return seccomp.SyscallRules{
-		syscall.SYS_IOCTL:           {},
+		syscall.SYS_IOCTL: {},
+		unix.SYS_MEMBARRIER: []seccomp.Rule{
+			{
+				seccomp.EqualTo(linux.MEMBARRIER_CMD_PRIVATE_EXPEDITED),
+				seccomp.EqualTo(0),
+			},
+		},
 		syscall.SYS_MMAP:            {},
 		syscall.SYS_RT_SIGSUSPEND:   {},
 		syscall.SYS_RT_SIGTIMEDWAIT: {},
diff --git a/pkg/sentry/platform/kvm/kvm.go b/pkg/sentry/platform/kvm/kvm.go
index d46946402..dd45ad10b 100644
--- a/pkg/sentry/platform/kvm/kvm.go
+++ b/pkg/sentry/platform/kvm/kvm.go
@@ -63,6 +63,9 @@ type runData struct {
 type KVM struct {
 	platform.NoCPUPreemptionDetection
 
+	// KVM never changes mm_structs.
+	platform.UseHostProcessMemoryBarrier
+
 	// machine is the backing VM.
 	machine *machine
 }
-- 
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