From 93de2a6a4b91b72607136dd656edf03fb399d27f Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Wed, 23 Sep 2026 09:37:21 -0700 Subject: KVM: SEV: Do cache maintenance on the source VM during intra-host migration Manually perform cache maintenance on the source VM during intra-host migration to ensure no stale data is left in CPU caches after the VM is destroyed. Because the source VM is "converted" to a non-SEV VM, KVM's memory reclaim flows won't trigger cache maintenance, e.g. when all guest memory is reclaimed in response to detaching from the mmu_notifier. Note, relying on the destination VM to do cache maintenance isn't an option as KVM doesn't require identical guest memory configurations, i.e. the source VM may have access to memory that the destination VM does not. Enforcing equivalent memory configurations is infeasible, as it would require a *deep* comparison of memslots, e.g. to verify that not only are the memslot identical, but what the memslots point at is also identical. Fixes: b56639318bb2 ("KVM: SEV: Add support for SEV intra host migration") Cc: stable@vger.kernel.org Reported-by: Stefan Teodorescu Signed-off-by: Sean Christopherson Message-ID: <20260923163721.1584779-3-seanjc@google.com> Signed-off-by: Paolo Bonzini --- tools/testing/selftests/ipc/.gitignore | 3 + tools/testing/selftests/ipc/Makefile | 18 +++ tools/testing/selftests/ipc/config | 2 + tools/testing/selftests/ipc/msgque.c | 256 +++++++++++++++++++++++++++++++++ 4 files changed, 279 insertions(+) create mode 100644 tools/testing/selftests/ipc/.gitignore create mode 100644 tools/testing/selftests/ipc/Makefile create mode 100644 tools/testing/selftests/ipc/config create mode 100644 tools/testing/selftests/ipc/msgque.c (limited to 'tools/testing/selftests/ipc') diff --git a/tools/testing/selftests/ipc/.gitignore b/tools/testing/selftests/ipc/.gitignore new file mode 100644 index 000000000..9ed280e4c --- /dev/null +++ b/tools/testing/selftests/ipc/.gitignore @@ -0,0 +1,3 @@ +# SPDX-License-Identifier: GPL-2.0-only +msgque_test +msgque diff --git a/tools/testing/selftests/ipc/Makefile b/tools/testing/selftests/ipc/Makefile new file mode 100644 index 000000000..fad10f2bb --- /dev/null +++ b/tools/testing/selftests/ipc/Makefile @@ -0,0 +1,18 @@ +# SPDX-License-Identifier: GPL-2.0 +ARCH ?= $(shell uname -m 2>/dev/null || echo not) +override ARCH := $(shell echo $(ARCH) | sed -e s/i.86/i386/) +ifeq ($(ARCH),i386) + override ARCH := x86 + CFLAGS := -DCONFIG_X86_32 -D__i386__ +endif +ifeq ($(ARCH),x86_64) + override ARCH := x86 + CFLAGS := -DCONFIG_X86_64 -D__x86_64__ +endif + +CFLAGS += $(KHDR_INCLUDES) + +TEST_GEN_PROGS := msgque + +include ../lib.mk + diff --git a/tools/testing/selftests/ipc/config b/tools/testing/selftests/ipc/config new file mode 100644 index 000000000..070244710 --- /dev/null +++ b/tools/testing/selftests/ipc/config @@ -0,0 +1,2 @@ +CONFIG_EXPERT=y +CONFIG_CHECKPOINT_RESTORE=y diff --git a/tools/testing/selftests/ipc/msgque.c b/tools/testing/selftests/ipc/msgque.c new file mode 100644 index 000000000..4b4c1abfa --- /dev/null +++ b/tools/testing/selftests/ipc/msgque.c @@ -0,0 +1,256 @@ +// SPDX-License-Identifier: GPL-2.0 +#define _GNU_SOURCE +#include +#include +#include +#include +#include +#include + +#include "kselftest.h" + +#define MAX_MSG_SIZE 32 + +struct msg1 { + int msize; + long mtype; + char mtext[MAX_MSG_SIZE]; +}; + +#define TEST_STRING "Test sysv5 msg" +#define MSG_TYPE 1 + +#define ANOTHER_TEST_STRING "Yet another test sysv5 msg" +#define ANOTHER_MSG_TYPE 26538 + +struct msgque_data { + key_t key; + int msq_id; + int qbytes; + int qnum; + int mode; + struct msg1 *messages; +}; + +int restore_queue(struct msgque_data *msgque) +{ + int fd, ret, id, i; + char buf[32]; + + fd = open("/proc/sys/kernel/msg_next_id", O_WRONLY); + if (fd == -1) { + ksft_test_result_fail("Failed to open /proc/sys/kernel/msg_next_id\n"); + return -errno; + } + sprintf(buf, "%d", msgque->msq_id); + + ret = write(fd, buf, strlen(buf)); + if (ret != strlen(buf)) { + ksft_test_result_fail("Failed to write to /proc/sys/kernel/msg_next_id\n"); + return -errno; + } + + id = msgget(msgque->key, msgque->mode | IPC_CREAT | IPC_EXCL); + if (id == -1) { + ksft_test_result_fail("Failed to create queue\n"); + return -errno; + } + + if (id != msgque->msq_id) { + ksft_test_result_fail("Restored queue has wrong id (%d instead of %d)\n" + , id, msgque->msq_id); + ret = -EFAULT; + goto destroy; + } + + for (i = 0; i < msgque->qnum; i++) { + if (msgsnd(msgque->msq_id, &msgque->messages[i].mtype, + msgque->messages[i].msize, IPC_NOWAIT) != 0) { + ksft_test_result_fail("msgsnd failed (%m)\n"); + ret = -errno; + goto destroy; + } + } + return 0; + +destroy: + if (msgctl(id, IPC_RMID, NULL)) + printf("Failed to destroy queue: %d\n", -errno); + return ret; +} + +int check_and_destroy_queue(struct msgque_data *msgque) +{ + struct msg1 message; + int cnt = 0, ret; + + while (1) { + ret = msgrcv(msgque->msq_id, &message.mtype, MAX_MSG_SIZE, + 0, IPC_NOWAIT); + if (ret < 0) { + if (errno == ENOMSG) + break; + ksft_test_result_fail("Failed to read IPC message: %m\n"); + ret = -errno; + goto err; + } + if (ret != msgque->messages[cnt].msize) { + ksft_test_result_fail("Wrong message size: %d (expected %d)\n", ret, msgque->messages[cnt].msize); + ret = -EINVAL; + goto err; + } + if (message.mtype != msgque->messages[cnt].mtype) { + ksft_test_result_fail("Wrong message type\n"); + ret = -EINVAL; + goto err; + } + if (memcmp(message.mtext, msgque->messages[cnt].mtext, ret)) { + ksft_test_result_fail("Wrong message content\n"); + ret = -EINVAL; + goto err; + } + cnt++; + } + + if (cnt != msgque->qnum) { + ksft_test_result_fail("Wrong message number\n"); + ret = -EINVAL; + goto err; + } + + ret = 0; +err: + if (msgctl(msgque->msq_id, IPC_RMID, NULL)) { + printf("Failed to destroy queue: %d\n", -errno); + return -errno; + } + return ret; +} + +int dump_queue(struct msgque_data *msgque) +{ + struct msqid_ds ds; + int kern_id; + int i, ret; + + for (kern_id = 0; kern_id < 256; kern_id++) { + ret = msgctl(kern_id, MSG_STAT, &ds); + if (ret < 0) { + if (errno == EINVAL) + continue; + ksft_test_result_fail("Failed to get stats for IPC queue with id %d\n", + kern_id); + return -errno; + } + + if (ret == msgque->msq_id) + break; + } + + msgque->messages = malloc(sizeof(struct msg1) * ds.msg_qnum); + if (msgque->messages == NULL) { + ksft_test_result_fail("Failed to get stats for IPC queue\n"); + return -ENOMEM; + } + + msgque->qnum = ds.msg_qnum; + msgque->mode = ds.msg_perm.mode; + msgque->qbytes = ds.msg_qbytes; + + for (i = 0; i < msgque->qnum; i++) { + ret = msgrcv(msgque->msq_id, &msgque->messages[i].mtype, + MAX_MSG_SIZE, i, IPC_NOWAIT | MSG_COPY); + if (ret < 0) { + if (errno == EOPNOTSUPP) + ksft_exit_skip("MSG_COPY not supported\n"); + + ksft_test_result_fail("Failed to copy IPC message: %m (%d)\n", errno); + return -errno; + } + msgque->messages[i].msize = ret; + } + return 0; +} + +int fill_msgque(struct msgque_data *msgque) +{ + struct msg1 msgbuf; + + msgbuf.mtype = MSG_TYPE; + memcpy(msgbuf.mtext, TEST_STRING, sizeof(TEST_STRING)); + if (msgsnd(msgque->msq_id, &msgbuf.mtype, sizeof(TEST_STRING), + IPC_NOWAIT) != 0) { + ksft_test_result_fail("First message send failed (%m)\n"); + return -errno; + } + + msgbuf.mtype = ANOTHER_MSG_TYPE; + memcpy(msgbuf.mtext, ANOTHER_TEST_STRING, sizeof(ANOTHER_TEST_STRING)); + if (msgsnd(msgque->msq_id, &msgbuf.mtype, sizeof(ANOTHER_TEST_STRING), + IPC_NOWAIT) != 0) { + ksft_test_result_fail("Second message send failed (%m)\n"); + return -errno; + } + return 0; +} + +int main(int argc, char **argv) +{ + int err; + struct msgque_data msgque; + + if (getuid() != 0) + ksft_exit_skip("Please run the test as root - Exiting.\n"); + + msgque.key = ftok(argv[0], 822155650); + if (msgque.key == -1) { + ksft_test_result_fail("Can't make key: %d\n", -errno); + ksft_exit_fail(); + } + + msgque.msq_id = msgget(msgque.key, IPC_CREAT | IPC_EXCL | 0666); + if (msgque.msq_id == -1) { + err = -errno; + ksft_test_result_fail("Can't create queue: %d\n", err); + goto err_out; + } + + err = fill_msgque(&msgque); + if (err) { + ksft_test_result_fail("Failed to fill queue: %d\n", err); + goto err_destroy; + } + + err = dump_queue(&msgque); + if (err) { + ksft_test_result_fail("Failed to dump queue: %d\n", err); + goto err_destroy; + } + + err = check_and_destroy_queue(&msgque); + if (err) { + ksft_test_result_fail("Failed to check and destroy queue: %d\n", err); + goto err_out; + } + + err = restore_queue(&msgque); + if (err) { + ksft_test_result_fail("Failed to restore queue: %d\n", err); + goto err_destroy; + } + + err = check_and_destroy_queue(&msgque); + if (err) { + ksft_test_result_fail("Failed to test queue: %d\n", err); + goto err_out; + } + ksft_exit_pass(); + +err_destroy: + if (msgctl(msgque.msq_id, IPC_RMID, NULL)) { + printf("Failed to destroy queue: %d\n", -errno); + ksft_exit_fail(); + } +err_out: + ksft_exit_fail(); +} -- cgit v1.3.1