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 --- drivers/firmware/imx/sm-cpu.c | 85 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 85 insertions(+) create mode 100644 drivers/firmware/imx/sm-cpu.c (limited to 'drivers/firmware/imx/sm-cpu.c') diff --git a/drivers/firmware/imx/sm-cpu.c b/drivers/firmware/imx/sm-cpu.c new file mode 100644 index 000000000..091b014f7 --- /dev/null +++ b/drivers/firmware/imx/sm-cpu.c @@ -0,0 +1,85 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright 2025 NXP + */ + +#include +#include +#include +#include +#include +#include + +static const struct scmi_imx_cpu_proto_ops *imx_cpu_ops; +static struct scmi_protocol_handle *ph; + +int scmi_imx_cpu_reset_vector_set(u32 cpuid, u64 vector, bool start, bool boot, + bool resume) +{ + if (!ph) + return -EPROBE_DEFER; + + return imx_cpu_ops->cpu_reset_vector_set(ph, cpuid, vector, start, + boot, resume); +} +EXPORT_SYMBOL(scmi_imx_cpu_reset_vector_set); + +int scmi_imx_cpu_start(u32 cpuid, bool start) +{ + if (!ph) + return -EPROBE_DEFER; + + if (start) + return imx_cpu_ops->cpu_start(ph, cpuid, true); + + return imx_cpu_ops->cpu_start(ph, cpuid, false); +}; +EXPORT_SYMBOL(scmi_imx_cpu_start); + +int scmi_imx_cpu_started(u32 cpuid, bool *started) +{ + if (!ph) + return -EPROBE_DEFER; + + if (!started) + return -EINVAL; + + return imx_cpu_ops->cpu_started(ph, cpuid, started); +}; +EXPORT_SYMBOL(scmi_imx_cpu_started); + +static int scmi_imx_cpu_probe(struct scmi_device *sdev) +{ + const struct scmi_handle *handle = sdev->handle; + + if (!handle) + return -ENODEV; + + if (imx_cpu_ops) { + dev_err(&sdev->dev, "sm cpu already initialized\n"); + return -EEXIST; + } + + imx_cpu_ops = handle->devm_protocol_get(sdev, SCMI_PROTOCOL_IMX_CPU, &ph); + if (IS_ERR(imx_cpu_ops)) + return PTR_ERR(imx_cpu_ops); + + return 0; +} + +static const struct scmi_device_id scmi_id_table[] = { + { SCMI_PROTOCOL_IMX_CPU, "imx-cpu" }, + { }, +}; +MODULE_DEVICE_TABLE(scmi, scmi_id_table); + +static struct scmi_driver scmi_imx_cpu_driver = { + .name = "scmi-imx-cpu", + .probe = scmi_imx_cpu_probe, + .id_table = scmi_id_table, +}; +module_scmi_driver(scmi_imx_cpu_driver); + +MODULE_AUTHOR("Peng Fan "); +MODULE_DESCRIPTION("IMX SM CPU driver"); +MODULE_LICENSE("GPL"); -- cgit v1.3.1