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/usbstring.c | 91 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 91 insertions(+) create mode 100644 drivers/usb/gadget/usbstring.c (limited to 'drivers/usb/gadget/usbstring.c') diff --git a/drivers/usb/gadget/usbstring.c b/drivers/usb/gadget/usbstring.c new file mode 100644 index 000000000..37a2f1b61 --- /dev/null +++ b/drivers/usb/gadget/usbstring.c @@ -0,0 +1,91 @@ +// SPDX-License-Identifier: LGPL-2.1+ +/* + * Copyright (C) 2003 David Brownell + */ + +#include +#include +#include +#include +#include +#include +#include + +#include +#include + + +/** + * usb_gadget_get_string - fill out a string descriptor + * @table: of c strings encoded using UTF-8 + * @id: string id, from low byte of wValue in get string descriptor + * @buf: at least 256 bytes, must be 16-bit aligned + * + * Finds the UTF-8 string matching the ID, and converts it into a + * string descriptor in utf16-le. + * Returns length of descriptor (always even) or negative errno + * + * If your driver needs stings in multiple languages, you'll probably + * "switch (wIndex) { ... }" in your ep0 string descriptor logic, + * using this routine after choosing which set of UTF-8 strings to use. + * Note that US-ASCII is a strict subset of UTF-8; any string bytes with + * the eighth bit set will be multibyte UTF-8 characters, not ISO-8859/1 + * characters (which are also widely used in C strings). + */ +int +usb_gadget_get_string (const struct usb_gadget_strings *table, int id, u8 *buf) +{ + struct usb_string *s; + int len; + + /* descriptor 0 has the language id */ + if (id == 0) { + buf [0] = 4; + buf [1] = USB_DT_STRING; + buf [2] = (u8) table->language; + buf [3] = (u8) (table->language >> 8); + return 4; + } + for (s = table->strings; s && s->s; s++) + if (s->id == id) + break; + + /* unrecognized: stall. */ + if (!s || !s->s) + return -EINVAL; + + /* string descriptors have length, tag, then UTF16-LE text */ + len = min_t(size_t, USB_MAX_STRING_LEN, strlen(s->s)); + len = utf8s_to_utf16s(s->s, len, UTF16_LITTLE_ENDIAN, + (wchar_t *) &buf[2], USB_MAX_STRING_LEN); + if (len < 0) + return -EINVAL; + buf [0] = (len + 1) * 2; + buf [1] = USB_DT_STRING; + return buf [0]; +} +EXPORT_SYMBOL_GPL(usb_gadget_get_string); + +/** + * usb_validate_langid - validate usb language identifiers + * @langid: usb language identifier + * + * Returns true for valid language identifier, otherwise false. + */ +bool usb_validate_langid(u16 langid) +{ + u16 primary_lang = langid & 0x3ff; /* bit [9:0] */ + u16 sub_lang = langid >> 10; /* bit [15:10] */ + + switch (primary_lang) { + case 0: + case 0x62 ... 0xfe: + case 0x100 ... 0x3ff: + return false; + } + if (!sub_lang) + return false; + + return true; +} +EXPORT_SYMBOL_GPL(usb_validate_langid); -- cgit v1.3.1