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/usb/gadget/functions.c | 117 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 117 insertions(+) create mode 100644 drivers/usb/gadget/functions.c (limited to 'drivers/usb/gadget/functions.c') diff --git a/drivers/usb/gadget/functions.c b/drivers/usb/gadget/functions.c new file mode 100644 index 000000000..70e31c40e --- /dev/null +++ b/drivers/usb/gadget/functions.c @@ -0,0 +1,117 @@ +// SPDX-License-Identifier: GPL-2.0 +#include +#include +#include +#include + +#include + +static LIST_HEAD(func_list); +static DEFINE_MUTEX(func_lock); + +static struct usb_function_instance *try_get_usb_function_instance(const char *name) +{ + struct usb_function_driver *fd; + struct usb_function_instance *fi; + + fi = ERR_PTR(-ENOENT); + mutex_lock(&func_lock); + list_for_each_entry(fd, &func_list, list) { + + if (strcmp(name, fd->name)) + continue; + + if (!try_module_get(fd->mod)) { + fi = ERR_PTR(-EBUSY); + break; + } + fi = fd->alloc_inst(); + if (IS_ERR(fi)) + module_put(fd->mod); + else + fi->fd = fd; + break; + } + mutex_unlock(&func_lock); + return fi; +} + +struct usb_function_instance *usb_get_function_instance(const char *name) +{ + struct usb_function_instance *fi; + int ret; + + fi = try_get_usb_function_instance(name); + if (!IS_ERR(fi)) + return fi; + ret = PTR_ERR(fi); + if (ret != -ENOENT) + return fi; + ret = request_module("usbfunc:%s", name); + if (ret < 0) + return ERR_PTR(ret); + return try_get_usb_function_instance(name); +} +EXPORT_SYMBOL_GPL(usb_get_function_instance); + +struct usb_function *usb_get_function(struct usb_function_instance *fi) +{ + struct usb_function *f; + + f = fi->fd->alloc_func(fi); + if (IS_ERR(f)) + return f; + f->fi = fi; + return f; +} +EXPORT_SYMBOL_GPL(usb_get_function); + +void usb_put_function_instance(struct usb_function_instance *fi) +{ + struct module *mod; + + if (!fi || !fi->fd) + return; + + mod = fi->fd->mod; + fi->free_func_inst(fi); + module_put(mod); +} +EXPORT_SYMBOL_GPL(usb_put_function_instance); + +void usb_put_function(struct usb_function *f) +{ + if (!f) + return; + + f->free_func(f); +} +EXPORT_SYMBOL_GPL(usb_put_function); + +int usb_function_register(struct usb_function_driver *newf) +{ + struct usb_function_driver *fd; + int ret; + + ret = -EEXIST; + + mutex_lock(&func_lock); + list_for_each_entry(fd, &func_list, list) { + if (!strcmp(fd->name, newf->name)) + goto out; + } + ret = 0; + list_add_tail(&newf->list, &func_list); +out: + mutex_unlock(&func_lock); + return ret; +} +EXPORT_SYMBOL_GPL(usb_function_register); + +void usb_function_unregister(struct usb_function_driver *fd) +{ + mutex_lock(&func_lock); + list_del(&fd->list); + mutex_unlock(&func_lock); +} +EXPORT_SYMBOL_GPL(usb_function_unregister); -- cgit v1.3.1