user/sven/linux.git/include/xen, branch v5.16.19

xen/gnttab: fix gnttab_end_foreign_access() without page specified

2022-03-11T11:42:10Z

Commit 42baefac638f06314298087394b982ead9ec444b upstream. gnttab_end_foreign_access() is used to free a grant reference and optionally to free the associated page. In case the grant is still in use by the other side processing is being deferred. This leads to a problem in case no page to be freed is specified by the caller: the caller doesn't know that the page is still mapped by the other side and thus should not be used for other purposes. The correct way to handle this situation is to take an additional reference to the granted page in case handling is being deferred and to drop that reference when the grant reference could be freed finally. This requires that there are no users of gnttab_end_foreign_access() left directly repurposing the granted page after the call, as this might result in clobbered data or information leaks via the not yet freed grant reference. This is part of CVE-2022-23041 / XSA-396. Reported-by: Simon Gaiser Signed-off-by: Juergen Gross Reviewed-by: Jan Beulich Signed-off-by: Greg Kroah-Hartman

xen: remove gnttab_query_foreign_access()

2022-03-11T11:42:09Z

Commit 1dbd11ca75fe664d3e54607547771d021f531f59 upstream. Remove gnttab_query_foreign_access(), as it is unused and unsafe to use. All previous use cases assumed a grant would not be in use after gnttab_query_foreign_access() returned 0. This information is useless in best case, as it only refers to a situation in the past, which could have changed already. Signed-off-by: Juergen Gross Reviewed-by: Jan Beulich Signed-off-by: Greg Kroah-Hartman

xen/grant-table: add gnttab_try_end_foreign_access()

2022-03-11T11:42:09Z

Commit 6b1775f26a2da2b05a6dc8ec2b5d14e9a4701a1a upstream. Add a new grant table function gnttab_try_end_foreign_access(), which will remove and free a grant if it is not in use. Its main use case is to either free a grant if it is no longer in use, or to take some other action if it is still in use. This other action can be an error exit, or (e.g. in the case of blkfront persistent grant feature) some special handling. This is CVE-2022-23036, CVE-2022-23038 / part of XSA-396. Reported-by: Demi Marie Obenour Signed-off-by: Juergen Gross Reviewed-by: Jan Beulich Signed-off-by: Greg Kroah-Hartman

xen/console: harden hvc_xen against event channel storms

2021-12-16T07:24:08Z

The Xen console driver is still vulnerable for an attack via excessive number of events sent by the backend. Fix that by using a lateeoi event channel. For the normal domU initial console this requires the introduction of bind_evtchn_to_irq_lateeoi() as there is no xenbus device available at the time the event channel is bound to the irq. As the decision whether an interrupt was spurious or not requires to test for bytes having been read from the backend, move sending the event into the if statement, as sending an event without having found any bytes to be read is making no sense at all. This is part of XSA-391 Signed-off-by: Juergen Gross Reviewed-by: Jan Beulich --- V2: - slightly adapt spurious irq detection (Jan Beulich) V3: - fix spurious irq detection (Jan Beulich)

xen: add "not_essential" flag to struct xenbus_driver

2021-11-23T19:41:29Z

When booting the xenbus driver will wait for PV devices to have connected to their backends before continuing. The timeout is different between essential and non-essential devices. Non-essential devices are identified by their nodenames directly in the xenbus driver, which requires to update this list in case a new device type being non-essential is added (this was missed for several types in the past). In order to avoid this problem, add a "not_essential" flag to struct xenbus_driver which can be set to "true" by the respective frontend. Set this flag for the frontends currently regarded to be not essential (vkbs and vfb) and use it for testing in the xenbus driver. Signed-off-by: Juergen Gross Link: https://lore.kernel.org/r/20211022064800.14978-2-jgross@suse.com Reviewed-by: Boris Ostrovsky Signed-off-by: Boris Ostrovsky

xen/balloon: rename alloc/free_xenballooned_pages

2021-11-04T17:59:44Z

alloc_xenballooned_pages() and free_xenballooned_pages() are used as direct replacements of xen_alloc_unpopulated_pages() and xen_free_unpopulated_pages() in case CONFIG_XEN_UNPOPULATED_ALLOC isn't defined. Guard both functions with !CONFIG_XEN_UNPOPULATED_ALLOC and rename them to the xen_*() variants they are replacing. This allows to remove some ifdeffery from the xen.h header file. Adapt the prototype of the functions to match. Signed-off-by: Juergen Gross Link: https://lore.kernel.org/r/20211102092234.17852-1-jgross@suse.com Reviewed-by: Boris Ostrovsky Signed-off-by: Boris Ostrovsky

xen: allow pv-only hypercalls only with CONFIG_XEN_PV

2021-11-02T13:11:01Z

Put the definitions of the hypercalls usable only by pv guests inside CONFIG_XEN_PV sections. On Arm two dummy functions related to pv hypercalls can be removed. While at it remove the no longer supported tmem hypercall definition. Signed-off-by: Juergen Gross Link: https://lore.kernel.org/r/20211028081221.2475-3-jgross@suse.com Reviewed-by: Boris Ostrovsky Signed-off-by: Boris Ostrovsky

xen-pciback: allow compiling on other archs than x86

2021-11-02T13:03:43Z

Xen-pciback driver was designed to be built for x86 only. But it can also be used by other architectures, e.g. Arm. Currently PCI backend implements multiple functionalities at a time, such as: 1. It is used as a database for assignable PCI devices, e.g. xl pci-assignable-{add|remove|list} manipulates that list. So, whenever the toolstack needs to know which PCI devices can be passed through it reads that from the relevant sysfs entries of the pciback. 2. It is used to hold the unbound PCI devices list, e.g. when passing through a PCI device it needs to be unbound from the relevant device driver and bound to pciback (strictly speaking it is not required that the device is bound to pciback, but pciback is again used as a database of the passed through PCI devices, so we can re-bind the devices back to their original drivers when guest domain shuts down) 3. Device reset for the devices being passed through 4. Para-virtualised use-cases support The para-virtualised part of the driver is not always needed as some architectures, e.g. Arm or x86 PVH Dom0, are not using backend-frontend model for PCI device passthrough. For such use-cases make the very first step in splitting the xen-pciback driver into two parts: Xen PCI stub and PCI PV backend drivers. For that add new configuration options CONFIG_XEN_PCI_STUB and CONFIG_XEN_PCIDEV_STUB, so the driver can be limited in its functionality, e.g. no support for para-virtualised scenario. x86 platform will continue using CONFIG_XEN_PCIDEV_BACKEND for the fully featured backend driver. Signed-off-by: Oleksandr Andrushchenko Signed-off-by: Anastasiia Lukianenko Reviewed-by: Stefano Stabellini Reviewed-by: Juergen Gross Link: https://lore.kernel.org/r/20211028143620.144936-1-andr2000@gmail.com Signed-off-by: Boris Ostrovsky

xen: fix wrong SPDX headers of Xen related headers

2021-11-02T12:45:44Z

Commit b24413180f5600 ("License cleanup: add SPDX GPL-2.0 license identifier to files with no license") was meant to do a tree-wide cleanup for files without any license information by adding a SPDX GPL-2.0 line to them. Unfortunately this was applied even to several Xen-related headers which have been originally under the MIT license, but obviously have been copied to the Linux tree from the Xen project without keeping the license boiler plate as required. Correct that by changing the license of those files back to "MIT". Some files still contain the MIT license text. Replace that by the related SPDX line. Signed-off-by: Juergen Gross Reviewed-by: Boris Ostrovsky Link: https://lore.kernel.org/r/20211015143312.29900-1-jgross@suse.com Signed-off-by: Boris Ostrovsky

xen/privcmd: drop "pages" parameter from xen_remap_pfn()

2021-10-05T06:20:27Z

The function doesn't use it and all of its callers say in a comment that their respective arguments are to be non-NULL only in auto-translated mode. Since xen_remap_domain_mfn_array() isn't supposed to be used by non-PV, drop the parameter there as well. It was bogusly passed as non- NULL (PRIV_VMA_LOCKED) by its only caller anyway. For xen_remap_domain_gfn_range(), otoh, it's not clear at all why this wouldn't want / might not need to gain auto-translated support down the road, so the parameter is retained there despite now remaining unused (and the only caller passing NULL); correct a respective comment as well. Signed-off-by: Jan Beulich Reviewed-by: Boris Ostrovsky Link: https://lore.kernel.org/r/036ad8a2-46f9-ac3d-6219-bdc93ab9e10b@suse.com Signed-off-by: Juergen Gross