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/acpi/proc.c | 143 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 143 insertions(+) create mode 100644 drivers/acpi/proc.c (limited to 'drivers/acpi/proc.c') diff --git a/drivers/acpi/proc.c b/drivers/acpi/proc.c new file mode 100644 index 000000000..c08ead072 --- /dev/null +++ b/drivers/acpi/proc.c @@ -0,0 +1,143 @@ +// SPDX-License-Identifier: GPL-2.0 +#include +#include +#include +#include +#include +#include +#include + +#include "sleep.h" +#include "internal.h" + +/* + * this file provides support for: + * /proc/acpi/wakeup + */ + +static int +acpi_system_wakeup_device_seq_show(struct seq_file *seq, void *offset) +{ + struct acpi_device *dev, *tmp; + + seq_printf(seq, "Device\tS-state\t Status Sysfs node\n"); + + mutex_lock(&acpi_device_lock); + list_for_each_entry_safe(dev, tmp, &acpi_wakeup_device_list, + wakeup_list) { + struct acpi_device_physical_node *entry; + + if (!dev->wakeup.flags.valid) + continue; + + seq_printf(seq, "%s\t S%llu\t", + dev->pnp.bus_id, + dev->wakeup.sleep_state); + + mutex_lock(&dev->physical_node_lock); + + if (!dev->physical_node_count) { + seq_printf(seq, "%c%-8s\n", + dev->wakeup.flags.valid ? '*' : ' ', + str_enabled_disabled(device_may_wakeup(&dev->dev))); + } else { + struct device *ldev; + list_for_each_entry(entry, &dev->physical_node_list, + node) { + ldev = get_device(entry->dev); + if (!ldev) + continue; + + if (&entry->node != + dev->physical_node_list.next) + seq_printf(seq, "\t\t"); + + seq_printf(seq, "%c%-8s %s:%s\n", + dev->wakeup.flags.valid ? '*' : ' ', + str_enabled_disabled(device_may_wakeup(ldev) || + device_may_wakeup(&dev->dev)), + ldev->bus ? ldev->bus->name : + "no-bus", dev_name(ldev)); + put_device(ldev); + } + } + + mutex_unlock(&dev->physical_node_lock); + } + mutex_unlock(&acpi_device_lock); + return 0; +} + +static void physical_device_enable_wakeup(struct acpi_device *adev) +{ + struct acpi_device_physical_node *entry; + + mutex_lock(&adev->physical_node_lock); + + list_for_each_entry(entry, + &adev->physical_node_list, node) + if (entry->dev && device_can_wakeup(entry->dev)) { + bool enable = !device_may_wakeup(entry->dev); + device_set_wakeup_enable(entry->dev, enable); + } + + mutex_unlock(&adev->physical_node_lock); +} + +static ssize_t +acpi_system_write_wakeup_device(struct file *file, + const char __user * buffer, + size_t count, loff_t * ppos) +{ + struct acpi_device *dev, *tmp; + char strbuf[5]; + char str[5] = ""; + + if (count > 4) + count = 4; + + if (copy_from_user(strbuf, buffer, count)) + return -EFAULT; + strbuf[count] = '\0'; + sscanf(strbuf, "%s", str); + + mutex_lock(&acpi_device_lock); + list_for_each_entry_safe(dev, tmp, &acpi_wakeup_device_list, + wakeup_list) { + if (!dev->wakeup.flags.valid) + continue; + + if (!strncmp(dev->pnp.bus_id, str, 4)) { + if (device_can_wakeup(&dev->dev)) { + bool enable = !device_may_wakeup(&dev->dev); + device_set_wakeup_enable(&dev->dev, enable); + } else { + physical_device_enable_wakeup(dev); + } + break; + } + } + mutex_unlock(&acpi_device_lock); + return count; +} + +static int +acpi_system_wakeup_device_open_fs(struct inode *inode, struct file *file) +{ + return single_open(file, acpi_system_wakeup_device_seq_show, + pde_data(inode)); +} + +static const struct proc_ops acpi_system_wakeup_device_proc_ops = { + .proc_open = acpi_system_wakeup_device_open_fs, + .proc_read = seq_read, + .proc_write = acpi_system_write_wakeup_device, + .proc_lseek = seq_lseek, + .proc_release = single_release, +}; + +void __init acpi_sleep_proc_init(void) +{ + /* 'wakeup device' [R/W] */ + proc_create("wakeup", 0644, acpi_root_dir, &acpi_system_wakeup_device_proc_ops); +} -- cgit v1.3.1