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* xen: privcmd: Add support for ioeventfdViresh Kumar2023-10-161-0/+51
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Virtio guests send VIRTIO_MMIO_QUEUE_NOTIFY notification when they need to notify the backend of an update to the status of the virtqueue. The backend or another entity, polls the MMIO address for updates to know when the notification is sent. It works well if the backend does this polling by itself. But as we move towards generic backend implementations, we end up implementing this in a separate user-space program. Generally, the Virtio backends are implemented to work with the Eventfd based mechanism. In order to make such backends work with Xen, another software layer needs to do the polling and send an event via eventfd to the backend once the notification from guest is received. This results in an extra context switch. This is not a new problem in Linux though. It is present with other hypervisors like KVM, etc. as well. The generic solution implemented in the kernel for them is to provide an IOCTL call to pass the address to poll and eventfd, which lets the kernel take care of polling and raise an event on the eventfd, instead of handling this in user space (which involves an extra context switch). This patch adds similar support for xen. Inspired by existing implementations for KVM, etc.. This also copies ioreq.h header file (only struct ioreq and related macros) from Xen's source tree (Top commit 5d84f07fe6bf ("xen/pci: drop remaining uses of bool_t")). Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Reviewed-by: Juergen Gross <jgross@suse.com> Link: https://lore.kernel.org/r/b20d83efba6453037d0c099912813c79c81f7714.1697439990.git.viresh.kumar@linaro.org Signed-off-by: Juergen Gross <jgross@suse.com>
* arm/xen: remove lazy mode related definitionsJuergen Gross2023-09-191-12/+0
| | | | | | | | | | | | | include/xen/arm/hypervisor.h contains definitions related to paravirt lazy mode, which are used nowhere in the code. All paravirt lazy mode related users are in x86 code, so remove the definitions on Arm side. Signed-off-by: Juergen Gross <jgross@suse.com> Acked-by: Stefano Stabellini <sstabellini@kernel.org> Link: https://lore.kernel.org/r/20230913113828.18421-2-jgross@suse.com Signed-off-by: Juergen Gross <jgross@suse.com>
* xen: simplify evtchn_do_upcall() call mazeJuergen Gross2023-09-191-2/+1
| | | | | | | | | | | | | | | | | | | | | | | There are several functions involved for performing the functionality of evtchn_do_upcall(): - __xen_evtchn_do_upcall() doing the real work - xen_hvm_evtchn_do_upcall() just being a wrapper for __xen_evtchn_do_upcall(), exposed for external callers - xen_evtchn_do_upcall() calling __xen_evtchn_do_upcall(), too, but without any user Simplify this maze by: - removing the unused xen_evtchn_do_upcall() - removing xen_hvm_evtchn_do_upcall() as the only left caller of __xen_evtchn_do_upcall(), while renaming __xen_evtchn_do_upcall() to xen_evtchn_do_upcall() Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Juergen Gross <jgross@suse.com>
* Merge tag 'dma-mapping-6.6-2023-08-29' of ↵Linus Torvalds2023-08-291-0/+6
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.infradead.org/users/hch/dma-mapping Pull dma-maping updates from Christoph Hellwig: - allow dynamic sizing of the swiotlb buffer, to cater for secure virtualization workloads that require all I/O to be bounce buffered (Petr Tesarik) - move a declaration to a header (Arnd Bergmann) - check for memory region overlap in dma-contiguous (Binglei Wang) - remove the somewhat dangerous runtime swiotlb-xen enablement and unexport is_swiotlb_active (Christoph Hellwig, Juergen Gross) - per-node CMA improvements (Yajun Deng) * tag 'dma-mapping-6.6-2023-08-29' of git://git.infradead.org/users/hch/dma-mapping: swiotlb: optimize get_max_slots() swiotlb: move slot allocation explanation comment where it belongs swiotlb: search the software IO TLB only if the device makes use of it swiotlb: allocate a new memory pool when existing pools are full swiotlb: determine potential physical address limit swiotlb: if swiotlb is full, fall back to a transient memory pool swiotlb: add a flag whether SWIOTLB is allowed to grow swiotlb: separate memory pool data from other allocator data swiotlb: add documentation and rename swiotlb_do_find_slots() swiotlb: make io_tlb_default_mem local to swiotlb.c swiotlb: bail out of swiotlb_init_late() if swiotlb is already allocated dma-contiguous: check for memory region overlap dma-contiguous: support numa CMA for specified node dma-contiguous: support per-numa CMA for all architectures dma-mapping: move arch_dma_set_mask() declaration to header swiotlb: unexport is_swiotlb_active x86: always initialize xen-swiotlb when xen-pcifront is enabling xen/pci: add flag for PCI passthrough being possible
| * xen/pci: add flag for PCI passthrough being possibleJuergen Gross2023-07-311-0/+6
| | | | | | | | | | | | | | | | | | | | | | | | When running as a Xen PV guests passed through PCI devices only have a chance to work if the Xen supplied memory map has some PCI space reserved. Add a flag xen_pv_pci_possible which will be set in early boot in case the memory map has at least one area with the type E820_TYPE_RESERVED. Signed-off-by: Juergen Gross <jgross@suse.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
* | xen/evtchn: Remove unused function declaration xen_set_affinity_evtchn()Yue Haibing2023-08-211-1/+0
|/ | | | | | | | | | | Commit 67473b8194bc ("xen/events: Remove disfunct affinity spreading") leave this unused declaration. Signed-off-by: Yue Haibing <yuehaibing@huawei.com> Reviewed-by: Juergen Gross <jgross@suse.com> Reviewed-by: Rahul Singh <rahul.singh@arm.com> Link: https://lore.kernel.org/r/20230801145413.40684-1-yuehaibing@huawei.com Signed-off-by: Juergen Gross <jgross@suse.com>
* xen/evtchn: Introduce new IOCTL to bind static evtchnRahul Singh2023-07-261-1/+10
| | | | | | | | | | | | | | | | | | | | | | | | | Xen 4.17 supports the creation of static evtchns. To allow user space application to bind static evtchns introduce new ioctl "IOCTL_EVTCHN_BIND_STATIC". Existing IOCTL doing more than binding that’s why we need to introduce the new IOCTL to only bind the static event channels. Static evtchns to be available for use during the lifetime of the guest. When the application exits, __unbind_from_irq() ends up being called from release() file operations because of that static evtchns are getting closed. To avoid closing the static event channel, add the new bool variable "is_static" in "struct irq_info" to mark the event channel static when creating the event channel to avoid closing the static evtchn. Also, take this opportunity to remove the open-coded version of the evtchn close in drivers/xen/evtchn.c file and use xen_evtchn_close(). Signed-off-by: Rahul Singh <rahul.singh@arm.com> Reviewed-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com> Acked-by: Stefano Stabellini <sstabellini@kernel.org> Link: https://lore.kernel.org/r/ae7329bf1713f83e4aad4f3fa0f316258c40a3e9.1689677042.git.rahul.singh@arm.com Signed-off-by: Juergen Gross <jgross@suse.com>
* x86: xen: add missing prototypesArnd Bergmann2023-06-261-0/+3
| | | | | | | | | | | | | | | | | | | | | | These function are all called from assembler files, or from inline assembler, so there is no immediate need for a prototype in a header, but if -Wmissing-prototypes is enabled, the compiler warns about them: arch/x86/xen/efi.c:130:13: error: no previous prototype for 'xen_efi_init' [-Werror=missing-prototypes] arch/x86/platform/pvh/enlighten.c:120:13: error: no previous prototype for 'xen_prepare_pvh' [-Werror=missing-prototypes] arch/x86/xen/enlighten_pv.c:1233:34: error: no previous prototype for 'xen_start_kernel' [-Werror=missing-prototypes] arch/x86/xen/irq.c:22:14: error: no previous prototype for 'xen_force_evtchn_callback' [-Werror=missing-prototypes] arch/x86/entry/common.c:302:24: error: no previous prototype for 'xen_pv_evtchn_do_upcall' [-Werror=missing-prototypes] Declare all of them in an appropriate header file to avoid the warnings. For consistency, also move the asm_cpu_bringup_and_idle() declaration out of smp_pv.c. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Link: https://lore.kernel.org/r/20230614073501.10101-3-jgross@suse.com Signed-off-by: Juergen Gross <jgross@suse.com>
* xen: xen_debug_interrupt prototype to global headerArnd Bergmann2023-06-261-0/+3
| | | | | | | | | | | | | | | The xen_debug_interrupt() function is only called on x86, which has a prototype in an architecture specific header, but the definition also exists on others, where the lack of a prototype causes a W=1 warning: drivers/xen/events/events_2l.c:264:13: error: no previous prototype for 'xen_debug_interrupt' [-Werror=missing-prototypes] Move the prototype into a global header instead to avoid this warning. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Stefano Stabellini <sstabellini@kernel.org> Link: https://lore.kernel.org/r/20230517124525.929201-1-arnd@kernel.org Signed-off-by: Juergen Gross <jgross@suse.com>
* ACPI: processor: Fix evaluating _PDC method when running as Xen dom0Roger Pau Monne2023-03-221-0/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In ACPI systems, the OS can direct power management, as opposed to the firmware. This OS-directed Power Management is called OSPM. Part of telling the firmware that the OS going to direct power management is making ACPI "_PDC" (Processor Driver Capabilities) calls. These _PDC methods must be evaluated for every processor object. If these _PDC calls are not completed for every processor it can lead to inconsistency and later failures in things like the CPU frequency driver. In a Xen system, the dom0 kernel is responsible for system-wide power management. The dom0 kernel is in charge of OSPM. However, the number of CPUs available to dom0 can be different than the number of CPUs physically present on the system. This leads to a problem: the dom0 kernel needs to evaluate _PDC for all the processors, but it can't always see them. In dom0 kernels, ignore the existing ACPI method for determining if a processor is physically present because it might not be accurate. Instead, ask the hypervisor for this information. Fix this by introducing a custom function to use when running as Xen dom0 in order to check whether a processor object matches a CPU that's online. Such checking is done using the existing information fetched by the Xen pCPU subsystem, extending it to also store the ACPI ID. This ensures that _PDC method gets evaluated for all physically online CPUs, regardless of the number of CPUs made available to dom0. Fixes: 5d554a7bb064 ("ACPI: processor: add internal processor_physically_present()") Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> Reviewed-by: Juergen Gross <jgross@suse.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* Merge tag 'for-linus-6.3-rc3-tag' of ↵Linus Torvalds2023-03-171-0/+3
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip Pull xen fixes from Juergen Gross: - cleanup for xen time handling - enable the VGA console in a Xen PVH dom0 - cleanup in the xenfs driver * tag 'for-linus-6.3-rc3-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: xen: remove unnecessary (void*) conversions x86/PVH: obtain VGA console info in Dom0 x86/xen/time: cleanup xen_tsc_safe_clocksource xen: update arch/x86/include/asm/xen/cpuid.h
| * x86/PVH: obtain VGA console info in Dom0Jan Beulich2023-03-141-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | A new platform-op was added to Xen to allow obtaining the same VGA console information PV Dom0 is handed. Invoke the new function and have the output data processed by xen_init_vga(). Signed-off-by: Jan Beulich <jbeulich@suse.com> Reviewed-by: Juergen Gross <jgross@suse.com> Link: https://lore.kernel.org/r/8f315e92-7bda-c124-71cc-478ab9c5e610@suse.com Signed-off-by: Juergen Gross <jgross@suse.com>
* | Merge tag 'driver-core-6.3-rc1' of ↵Linus Torvalds2023-02-241-5/+2
|\ \ | |/ |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core Pull driver core updates from Greg KH: "Here is the large set of driver core changes for 6.3-rc1. There's a lot of changes this development cycle, most of the work falls into two different categories: - fw_devlink fixes and updates. This has gone through numerous review cycles and lots of review and testing by lots of different devices. Hopefully all should be good now, and Saravana will be keeping a watch for any potential regression on odd embedded systems. - driver core changes to work to make struct bus_type able to be moved into read-only memory (i.e. const) The recent work with Rust has pointed out a number of areas in the driver core where we are passing around and working with structures that really do not have to be dynamic at all, and they should be able to be read-only making things safer overall. This is the contuation of that work (started last release with kobject changes) in moving struct bus_type to be constant. We didn't quite make it for this release, but the remaining patches will be finished up for the release after this one, but the groundwork has been laid for this effort. Other than that we have in here: - debugfs memory leak fixes in some subsystems - error path cleanups and fixes for some never-able-to-be-hit codepaths. - cacheinfo rework and fixes - Other tiny fixes, full details are in the shortlog All of these have been in linux-next for a while with no reported problems" [ Geert Uytterhoeven points out that that last sentence isn't true, and that there's a pending report that has a fix that is queued up - Linus ] * tag 'driver-core-6.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (124 commits) debugfs: drop inline constant formatting for ERR_PTR(-ERROR) OPP: fix error checking in opp_migrate_dentry() debugfs: update comment of debugfs_rename() i3c: fix device.h kernel-doc warnings dma-mapping: no need to pass a bus_type into get_arch_dma_ops() driver core: class: move EXPORT_SYMBOL_GPL() lines to the correct place Revert "driver core: add error handling for devtmpfs_create_node()" Revert "devtmpfs: add debug info to handle()" Revert "devtmpfs: remove return value of devtmpfs_delete_node()" driver core: cpu: don't hand-override the uevent bus_type callback. devtmpfs: remove return value of devtmpfs_delete_node() devtmpfs: add debug info to handle() driver core: add error handling for devtmpfs_create_node() driver core: bus: update my copyright notice driver core: bus: add bus_get_dev_root() function driver core: bus: constify bus_unregister() driver core: bus: constify some internal functions driver core: bus: constify bus_get_kset() driver core: bus: constify bus_register/unregister_notifier() driver core: remove private pointer from struct bus_type ...
| * driver core: make struct bus_type.uevent() take a const *Greg Kroah-Hartman2023-01-271-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | The uevent() callback in struct bus_type should not be modifying the device that is passed into it, so mark it as a const * and propagate the function signature changes out into all relevant subsystems that use this callback. Acked-by: Rafael J. Wysocki <rafael@kernel.org> Acked-by: Hans de Goede <hdegoede@redhat.com> Link: https://lore.kernel.org/r/20230111113018.459199-16-gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * xen/xenbus: move to_xenbus_device() to use container_of_const()Greg Kroah-Hartman2023-01-271-4/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The driver core is changing to pass some pointers as const, so move to_xenbus_device() to use container_of_const() to handle this change. to_xenbus_device() now properly keeps the const-ness of the pointer passed into it, while as before it could be lost. Cc: Stefano Stabellini <sstabellini@kernel.org> Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com> Cc: xen-devel@lists.xenproject.org Acked-by: Juergen Gross <jgross@suse.com> Acked-by: Hans de Goede <hdegoede@redhat.com> Link: https://lore.kernel.org/r/20230111113018.459199-15-gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | xen: Allow platform PCI interrupt to be sharedDavid Woodhouse2023-02-131-1/+1
|/ | | | | | | | | | | | | | | | | | | | | | | | When we don't use the per-CPU vector callback, we ask Xen to deliver event channel interrupts as INTx on the PCI platform device. As such, it can be shared with INTx on other PCI devices. Set IRQF_SHARED, and make it return IRQ_HANDLED or IRQ_NONE according to whether the evtchn_upcall_pending flag was actually set. Now I can share the interrupt: 11: 82 0 IO-APIC 11-fasteoi xen-platform-pci, ens4 Drop the IRQF_TRIGGER_RISING. It has no effect when the IRQ is shared, and besides, the only effect it was having even beforehand was to trigger a debug message in both I/OAPIC and legacy PIC cases: [ 0.915441] genirq: No set_type function for IRQ 11 (IO-APIC) [ 0.951939] genirq: No set_type function for IRQ 11 (XT-PIC) Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Reviewed-by: Juergen Gross <jgross@suse.com> Link: https://lore.kernel.org/r/f9a29a68d05668a3636dd09acd94d970269eaec6.camel@infradead.org Signed-off-by: Juergen Gross <jgross@suse.com>
* xen: make remove callback of xen driver void returnedDawei Li2022-12-151-1/+1
| | | | | | | | | | | | | | Since commit fc7a6209d571 ("bus: Make remove callback return void") forces bus_type::remove be void-returned, it doesn't make much sense for any bus based driver implementing remove callbalk to return non-void to its caller. This change is for xen bus based drivers. Acked-by: Juergen Gross <jgross@suse.com> Signed-off-by: Dawei Li <set_pte_at@outlook.com> Link: https://lore.kernel.org/r/TYCP286MB23238119AB4DF190997075C9CAE39@TYCP286MB2323.JPNP286.PROD.OUTLOOK.COM Signed-off-by: Juergen Gross <jgross@suse.com>
* xen: fix xen.h build for CONFIG_XEN_PVH=yJani Nikula2022-12-051-2/+2
| | | | | | | | | | For CONFIG_XEN_PVH=y, xen.h uses bool before the type is known. Include <linux/types.h> earlier. Signed-off-by: Jani Nikula <jani.nikula@intel.com> Reviewed-by: Juergen Gross <jgross@suse.com> Link: https://lore.kernel.org/r/20221123131057.3864183-1-jani.nikula@intel.com Signed-off-by: Juergen Gross <jgross@suse.com>
* xen/virtio: Optimize the setup of "xen-grant-dma" devicesOleksandr Tyshchenko2022-12-052-19/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | This is needed to avoid having to parse the same device-tree several times for a given device. For this to work we need to install the xen_virtio_restricted_mem_acc callback in Arm's xen_guest_init() which is same callback as x86's PV and HVM modes already use and remove the manual assignment in xen_setup_dma_ops(). Also we need to split the code to initialize backend_domid into a separate function. Prior to current patch we parsed the device-tree three times: 1. xen_setup_dma_ops()->...->xen_is_dt_grant_dma_device() 2. xen_setup_dma_ops()->...->xen_dt_grant_init_backend_domid() 3. xen_virtio_mem_acc()->...->xen_is_dt_grant_dma_device() With current patch we parse the device-tree only once in xen_virtio_restricted_mem_acc()->...->xen_dt_grant_init_backend_domid() Other benefits are: - Not diverge from x86 when setting up Xen grant DMA ops - Drop several global functions Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com> Reviewed-by: Xenia Ragiadakou <burzalodowa@gmail.com> Reviewed-by: Stefano Stabellini <sstabellini@kernel.org> Link: https://lore.kernel.org/r/20221025162004.8501-2-olekstysh@gmail.com Signed-off-by: Juergen Gross <jgross@suse.com>
* xen/virtio: enable grant based virtio on x86Juergen Gross2022-10-101-0/+6
| | | | | | | | | | Use an x86-specific virtio_check_mem_acc_cb() for Xen in order to setup the correct DMA ops. Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com> # common code Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by: Juergen Gross <jgross@suse.com>
* x86/xen: Add support for HVMOP_set_evtchn_upcall_vectorJane Malalane2022-08-122-0/+21
| | | | | | | | | | | | | | | | | | Implement support for the HVMOP_set_evtchn_upcall_vector hypercall in order to set the per-vCPU event channel vector callback on Linux and use it in preference of HVM_PARAM_CALLBACK_IRQ. If the per-VCPU vector setup is successful on BSP, use this method for the APs. If not, fallback to the global vector-type callback. Also register callback_irq at per-vCPU event channel setup to trick toolstack to think the domain is enlightened. Suggested-by: "Roger Pau Monné" <roger.pau@citrix.com> Signed-off-by: Jane Malalane <jane.malalane@citrix.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Link: https://lore.kernel.org/r/20220729070416.23306-1-jane.malalane@citrix.com Signed-off-by: Juergen Gross <jgross@suse.com>
* xen: don't require virtio with grants for non-PV guestsJuergen Gross2022-08-012-8/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit fa1f57421e0b ("xen/virtio: Enable restricted memory access using Xen grant mappings") introduced a new requirement for using virtio devices: the backend now needs to support the VIRTIO_F_ACCESS_PLATFORM feature. This is an undue requirement for non-PV guests, as those can be operated with existing backends without any problem, as long as those backends are running in dom0. Per default allow virtio devices without grant support for non-PV guests. On Arm require VIRTIO_F_ACCESS_PLATFORM for devices having been listed in the device tree to use grants. Add a new config item to always force use of grants for virtio. Fixes: fa1f57421e0b ("xen/virtio: Enable restricted memory access using Xen grant mappings") Reported-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com> Tested-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com> # Arm64 guest using Xen Reviewed-by: Stefano Stabellini <sstabellini@kernel.org> Link: https://lore.kernel.org/r/20220622063838.8854-4-jgross@suse.com Signed-off-by: Juergen Gross <jgross@suse.com>
* virtio: replace restricted mem access flag with callbackJuergen Gross2022-08-011-2/+2
| | | | | | | | | | | | | | | | | | | | Instead of having a global flag to require restricted memory access for all virtio devices, introduce a callback which can select that requirement on a per-device basis. For convenience add a common function returning always true, which can be used for use cases like SEV. Per default use a callback always returning false. As the callback needs to be set in early init code already, add a virtio anchor which is builtin in case virtio is enabled. Signed-off-by: Juergen Gross <jgross@suse.com> Tested-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com> # Arm64 guest using Xen Reviewed-by: Stefano Stabellini <sstabellini@kernel.org> Link: https://lore.kernel.org/r/20220622063838.8854-2-jgross@suse.com Signed-off-by: Juergen Gross <jgross@suse.com>
* arm/xen: Assign xen-grant DMA ops for xen-grant DMA devicesOleksandr Tyshchenko2022-06-061-1/+4
| | | | | | | | | | | | | | By assigning xen-grant DMA ops we will restrict memory access for passed device using Xen grant mappings. This is needed for using any virtualized device (e.g. virtio) in Xen guests in a safe manner. Please note, for the virtio devices the XEN_VIRTIO config should be enabled (it forces ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS). Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com> Reviewed-by: Stefano Stabellini <sstabellini@kernel.org> Link: https://lore.kernel.org/r/1654197833-25362-9-git-send-email-olekstysh@gmail.com Signed-off-by: Juergen Gross <jgross@suse.com>
* xen/grant-dma-ops: Retrieve the ID of backend's domain for DT devicesOleksandr Tyshchenko2022-06-061-0/+5
| | | | | | | | | | | | | | | | | | | | | | | Use the presence of "iommus" property pointed to the IOMMU node with recently introduced "xen,grant-dma" compatible as a clear indicator of enabling Xen grant mappings scheme for that device and read the ID of Xen domain where the corresponding backend is running. The domid (domain ID) is used as an argument to the Xen grant mapping APIs. To avoid the deferred probe timeout which takes place after reusing generic IOMMU device tree bindings (because the IOMMU device never becomes available) enable recently introduced stub IOMMU driver by selecting XEN_GRANT_DMA_IOMMU. Also introduce xen_is_grant_dma_device() to check whether xen-grant DMA ops need to be set for a passed device. Remove the hardcoded domid 0 in xen_grant_setup_dma_ops(). Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com> Reviewed-by: Stefano Stabellini <sstabellini@kernel.org> Link: https://lore.kernel.org/r/1654197833-25362-8-git-send-email-olekstysh@gmail.com Signed-off-by: Juergen Gross <jgross@suse.com>
* xen/virtio: Enable restricted memory access using Xen grant mappingsJuergen Gross2022-06-061-0/+8
| | | | | | | | | | | | | | | | In order to support virtio in Xen guests add a config option XEN_VIRTIO enabling the user to specify whether in all Xen guests virtio should be able to access memory via Xen grant mappings only on the host side. Also set PLATFORM_VIRTIO_RESTRICTED_MEM_ACCESS feature from the guest initialization code on Arm and x86 if CONFIG_XEN_VIRTIO is enabled. Signed-off-by: Juergen Gross <jgross@suse.com> Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com> Reviewed-by: Stefano Stabellini <sstabellini@kernel.org> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Link: https://lore.kernel.org/r/1654197833-25362-5-git-send-email-olekstysh@gmail.com Signed-off-by: Juergen Gross <jgross@suse.com>
* xen/grant-dma-ops: Add option to restrict memory access under XenJuergen Gross2022-06-061-0/+8
| | | | | | | | | | | | | | | | | | Introduce Xen grant DMA-mapping layer which contains special DMA-mapping routines for providing grant references as DMA addresses to be used by frontends (e.g. virtio) in Xen guests. Add the needed functionality by providing a special set of DMA ops handling the needed grant operations for the I/O pages. The subsequent commit will introduce the use case for xen-grant DMA ops layer to enable using virtio devices in Xen guests in a safe manner. Signed-off-by: Juergen Gross <jgross@suse.com> Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com> Reviewed-by: Stefano Stabellini <sstabellini@kernel.org> Link: https://lore.kernel.org/r/1654197833-25362-4-git-send-email-olekstysh@gmail.com Signed-off-by: Juergen Gross <jgross@suse.com>
* xen/grants: support allocating consecutive grantsJuergen Gross2022-06-061-0/+4
| | | | | | | | | | | | | | | For support of virtio via grant mappings in rare cases larger mappings using consecutive grants are needed. Support those by adding a bitmap of free grants. As consecutive grants will be needed only in very rare cases (e.g. when configuring a virtio device with a multi-page ring), optimize for the normal case of non-consecutive allocations. Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Link: https://lore.kernel.org/r/1654197833-25362-3-git-send-email-olekstysh@gmail.com Signed-off-by: Juergen Gross <jgross@suse.com>
* arm/xen: Introduce xen_setup_dma_ops()Oleksandr Tyshchenko2022-06-061-0/+15
| | | | | | | | | | | | | | | | | This patch introduces new helper and places it in new header. The helper's purpose is to assign any Xen specific DMA ops in a single place. For now, we deal with xen-swiotlb DMA ops only. The one of the subsequent commits in current series will add xen-grant DMA ops case. Also re-use the xen_swiotlb_detect() check on Arm32. Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com> Reviewed-by: Stefano Stabellini <sstabellini@kernel.org> [For arm64] Acked-by: Catalin Marinas <catalin.marinas@arm.com> Link: https://lore.kernel.org/r/1654197833-25362-2-git-send-email-olekstysh@gmail.com Signed-off-by: Juergen Gross <jgross@suse.com>
* Merge tag 'for-linus-5.19-rc1b-tag' of ↵Linus Torvalds2022-06-042-6/+3
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip Pull more xen updates from Juergen Gross: "Two cleanup patches for Xen related code and (more important) an update of MAINTAINERS for Xen, as Boris Ostrovsky decided to step down" * tag 'for-linus-5.19-rc1b-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: xen: replace xen_remap() with memremap() MAINTAINERS: Update Xen maintainership xen: switch gnttab_end_foreign_access() to take a struct page pointer
| * xen: replace xen_remap() with memremap()Juergen Gross2022-06-011-3/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | xen_remap() is used to establish mappings for frames not under direct control of the kernel: for Xenstore and console ring pages, and for grant pages of non-PV guests. Today xen_remap() is defined to use ioremap() on x86 (doing uncached mappings), and ioremap_cache() on Arm (doing cached mappings). Uncached mappings for those use cases are bad for performance, so they should be avoided if possible. As all use cases of xen_remap() don't require uncached mappings (the mapped area is always physical RAM), a mapping using the standard WB cache mode is fine. As sparse is flagging some of the xen_remap() use cases to be not appropriate for iomem(), as the result is not annotated with the __iomem modifier, eliminate xen_remap() completely and replace all use cases with memremap() specifying the MEMREMAP_WB caching mode. xen_unmap() can be replaced with memunmap(). Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Acked-by: Stefano Stabellini <sstabellini@kernel.org> Link: https://lore.kernel.org/r/20220530082634.6339-1-jgross@suse.com Signed-off-by: Juergen Gross <jgross@suse.com>
| * xen: switch gnttab_end_foreign_access() to take a struct page pointerJuergen Gross2022-05-271-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Instead of a virtual kernel address use a pointer of the associated struct page as second parameter of gnttab_end_foreign_access(). Most users have that pointer available already and are creating the virtual address from it, risking problems in case the memory is located in highmem. gnttab_end_foreign_access() itself won't need to get the struct page from the address again. Suggested-by: Jan Beulich <jbeulich@suse.com> Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: Jan Beulich <jbeulich@suse.com> Signed-off-by: Juergen Gross <jgross@suse.com>
* | Merge tag 'dma-mapping-5.19-2022-05-25' of ↵Linus Torvalds2022-05-254-30/+0
|\ \ | |/ |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.infradead.org/users/hch/dma-mapping Pull dma-mapping updates from Christoph Hellwig: - don't over-decrypt memory (Robin Murphy) - takes min align mask into account for the swiotlb max mapping size (Tianyu Lan) - use GFP_ATOMIC in dma-debug (Mikulas Patocka) - fix DMA_ATTR_NO_KERNEL_MAPPING on xen/arm (me) - don't fail on highmem CMA pages in dma_direct_alloc_pages (me) - cleanup swiotlb initialization and share more code with swiotlb-xen (me, Stefano Stabellini) * tag 'dma-mapping-5.19-2022-05-25' of git://git.infradead.org/users/hch/dma-mapping: (23 commits) dma-direct: don't over-decrypt memory swiotlb: max mapping size takes min align mask into account swiotlb: use the right nslabs-derived sizes in swiotlb_init_late swiotlb: use the right nslabs value in swiotlb_init_remap swiotlb: don't panic when the swiotlb buffer can't be allocated dma-debug: change allocation mode from GFP_NOWAIT to GFP_ATIOMIC dma-direct: don't fail on highmem CMA pages in dma_direct_alloc_pages swiotlb-xen: fix DMA_ATTR_NO_KERNEL_MAPPING on arm x86: remove cruft from <asm/dma-mapping.h> swiotlb: remove swiotlb_init_with_tbl and swiotlb_init_late_with_tbl swiotlb: merge swiotlb-xen initialization into swiotlb swiotlb: provide swiotlb_init variants that remap the buffer swiotlb: pass a gfp_mask argument to swiotlb_init_late swiotlb: add a SWIOTLB_ANY flag to lift the low memory restriction swiotlb: make the swiotlb_init interface more useful x86: centralize setting SWIOTLB_FORCE when guest memory encryption is enabled x86: remove the IOMMU table infrastructure MIPS/octeon: use swiotlb_init instead of open coding it arm/xen: don't check for xen_initial_domain() in xen_create_contiguous_region swiotlb: rename swiotlb_late_init_with_default_size ...
| * swiotlb-xen: fix DMA_ATTR_NO_KERNEL_MAPPING on armChristoph Hellwig2022-05-113-33/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | swiotlb-xen uses very different ways to allocate coherent memory on x86 vs arm. On the former it allocates memory from the page allocator, while on the later it reuses the dma-direct allocator the handles the complexities of non-coherent DMA on arm platforms. Unfortunately the complexities of trying to deal with the two cases in the swiotlb-xen.c code lead to a bug in the handling of DMA_ATTR_NO_KERNEL_MAPPING on arm. With the DMA_ATTR_NO_KERNEL_MAPPING flag the coherent memory allocator does not actually allocate coherent memory, but just a DMA handle for some memory that is DMA addressable by the device, but which does not have to have a kernel mapping. Thus dereferencing the return value will lead to kernel crashed and memory corruption. Fix this by using the dma-direct allocator directly for arm, which works perfectly fine because on arm swiotlb-xen is only used when the domain is 1:1 mapped, and then simplifying the remaining code to only cater for the x86 case with DMA coherent device. Reported-by: Rahul Singh <Rahul.Singh@arm.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Rahul Singh <rahul.singh@arm.com> Reviewed-by: Stefano Stabellini <sstabellini@kernel.org> Tested-by: Rahul Singh <rahul.singh@arm.com>
| * swiotlb: merge swiotlb-xen initialization into swiotlbChristoph Hellwig2022-04-182-3/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Reuse the generic swiotlb initialization for xen-swiotlb. For ARM/ARM64 this works trivially, while for x86 xen_swiotlb_fixup needs to be passed as the remap argument to swiotlb_init_remap/swiotlb_init_late. Note that the lower bound of the swiotlb size is changed to the smaller IO_TLB_MIN_SLABS based value with this patch, but that is fine as the 2MB value used in Xen before was just an optimization and is not the hard lower bound. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Stefano Stabellini <sstabellini@kernel.org> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Tested-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
* | xen: sync xs_wire.h header with upstream xenStefano Stabellini2022-05-191-4/+33
| | | | | | | | | | | | | | | | | | Sync the xs_wire.h header file in Linux with the one in Xen. Signed-off-by: Stefano Stabellini <stefano.stabellini@xilinx.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Link: https://lore.kernel.org/r/20220513211938.719341-1-sstabellini@kernel.org Signed-off-by: Juergen Gross <jgross@suse.com>
* | xen/xenbus: eliminate xenbus_grant_ring()Juergen Gross2022-05-191-2/+0
| | | | | | | | | | | | | | | | | | | | There is no external user of xenbus_grant_ring() left, so merge it into the only caller xenbus_setup_ring(). Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by: Juergen Gross <jgross@suse.com>
* | xen/xenbus: add xenbus_setup_ring() service functionJuergen Gross2022-05-191-0/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Most PV device frontends share very similar code for setting up shared ring buffers: - allocate page(s) - init the ring admin data - give the backend access to the ring via grants Tearing down the ring requires similar actions in all frontends again: - remove grants - free the page(s) Provide service functions xenbus_setup_ring() and xenbus_teardown_ring() for that purpose. Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by: Juergen Gross <jgross@suse.com>
* | xen: update ring.hJuergen Gross2022-05-191-5/+14
| | | | | | | | | | | | | | | | | | | | | | | | Update include/xen/interface/io/ring.h to its newest version. Switch the two improper use cases of RING_HAS_UNCONSUMED_RESPONSES() to XEN_RING_NR_UNCONSUMED_RESPONSES() in order to avoid the nasty XEN_RING_HAS_UNCONSUMED_IS_BOOL #define. Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by: Juergen Gross <jgross@suse.com>
* | xen: update grant_table.hJuergen Gross2022-05-192-63/+100
| | | | | | | | | | | | | | | | | | | | | | Update include/xen/interface/grant_table.h to its newest version. This allows to drop some private definitions in grant-table.c and include/xen/grant_table.h. Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by: Juergen Gross <jgross@suse.com>
* | xen: update vscsiif.hJuergen Gross2022-05-191-4/+129
|/ | | | | | | | | Update include/xen/interface/io/vscsiif.h to its newest version. Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Link: https://lore.kernel.org/r/20220428075323.12853-2-jgross@suse.com Signed-off-by: Juergen Gross <jgross@suse.com>
* xen/grant-table: remove readonly parameter from functionsJuergen Gross2022-03-151-3/+2
| | | | | | | | | | | | The gnttab_end_foreign_access() family of functions is taking a "readonly" parameter, which isn't used. Remove it from the function parameters. Signed-off-by: Juergen Gross <jgross@suse.com> Link: https://lore.kernel.org/r/20220311103429.12845-3-jgross@suse.com Reviewed-by: Jan Beulich <jbeulich@suse.com> Acked-by: Christian Schoenebeck <qemu_oss@crudebyte.com> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
* xen/grant-table: remove gnttab_*transfer*() functionsJuergen Gross2022-03-151-8/+0
| | | | | | | | | | | | | All grant table operations related to the "transfer" functionality are unused currently. There have been users in the old days of the "Xen-o-Linux" kernel, but those didn't make it upstream. So remove the "transfer" related functions. Signed-off-by: Juergen Gross <jgross@suse.com> Link: https://lore.kernel.org/r/20220311103429.12845-2-jgross@suse.com Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
* xen/gnttab: fix gnttab_end_foreign_access() without page specifiedJuergen Gross2022-03-071-1/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 <simon@invisiblethingslab.com> Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: Jan Beulich <jbeulich@suse.com> --- V4: - expand comment in header V5: - get page ref in case of kmalloc() failure, too
* xen: remove gnttab_query_foreign_access()Juergen Gross2022-03-071-2/+0
| | | | | | | | | | | | | 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 <jgross@suse.com> Reviewed-by: Jan Beulich <jbeulich@suse.com>
* xen/grant-table: add gnttab_try_end_foreign_access()Juergen Gross2022-03-071-0/+12
| | | | | | | | | | | | | | | | | | | | | 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 <demi@invisiblethingslab.com> Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: Jan Beulich <jbeulich@suse.com> --- V2: - new patch V4: - add comments to header (Jan Beulich)
* xen: xenbus_dev.h: delete incorrect file nameRandy Dunlap2022-02-031-2/+0
| | | | | | | | | | | | | | | It is better/preferred not to include file names in source files because (a) they are not needed and (b) they can be incorrect, so just delete this incorrect file name. Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Reviewed-by: Juergen Gross <jgross@suse.com> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Juergen Gross <jgross@suse.com> Cc: Stefano Stabellini <sstabellini@kernel.org> Cc: xen-devel@lists.xenproject.org Link: https://lore.kernel.org/r/20220130191705.24971-1-rdunlap@infradead.org Signed-off-by: Juergen Gross <jgross@suse.com>
* Merge tag 'for-linus-5.17-rc1-tag' of ↵Linus Torvalds2022-01-123-0/+22
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip Pull xen updates from Juergen Gross: - a fix for the Xen gntdev driver - a fix for running as Xen dom0 booted via EFI and the EFI framebuffer being located above 4GB - a series for support of mapping other guest's memory by using zone device when running as Xen guest on Arm * tag 'for-linus-5.17-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: dt-bindings: xen: Clarify "reg" purpose arm/xen: Read extended regions from DT and init Xen resource xen/unpopulated-alloc: Add mechanism to use Xen resource xen/balloon: Bring alloc(free)_xenballooned_pages helpers back arm/xen: Switch to use gnttab_setup_auto_xlat_frames() for DT xen/unpopulated-alloc: Drop check for virt_addr_valid() in fill_list() xen/x86: obtain upper 32 bits of video frame buffer address for Dom0 xen/gntdev: fix unmap notification order
| * xen/unpopulated-alloc: Add mechanism to use Xen resourceOleksandr Tyshchenko2022-01-061-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The main reason of this change is that unpopulated-alloc code cannot be used in its current form on Arm, but there is a desire to reuse it to avoid wasting real RAM pages for the grant/foreign mappings. The problem is that system "iomem_resource" is used for the address space allocation, but the really unallocated space can't be figured out precisely by the domain on Arm without hypervisor involvement. For example, not all device I/O regions are known by the time domain starts creating grant/foreign mappings. And following the advise from "iomem_resource" we might end up reusing these regions by a mistake. So, the hypervisor which maintains the P2M for the domain is in the best position to provide unused regions of guest physical address space which could be safely used to create grant/foreign mappings. Introduce new helper arch_xen_unpopulated_init() which purpose is to create specific Xen resource based on the memory regions provided by the hypervisor to be used as unused space for Xen scratch pages. If arch doesn't define arch_xen_unpopulated_init() the default "iomem_resource" will be used. Update the arguments list of allocate_resource() in fill_list() to always allocate a region from the hotpluggable range (maximum possible addressable physical memory range for which the linear mapping could be created). If arch doesn't define arch_get_mappable_range() the default range (0,-1) will be used. The behaviour on x86 won't be changed by current patch as both arch_xen_unpopulated_init() and arch_get_mappable_range() are not implemented for it. Also fallback to allocate xenballooned pages (balloon out RAM pages) if we do not have any suitable resource to work with (target_resource is invalid) and as the result we won't be able to provide unpopulated pages on a request. Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com> Reviewed-by: Stefano Stabellini <sstabellini@kernel.org> Link: https://lore.kernel.org/r/1639080336-26573-5-git-send-email-olekstysh@gmail.com Signed-off-by: Juergen Gross <jgross@suse.com>
| * xen/balloon: Bring alloc(free)_xenballooned_pages helpers backOleksandr Tyshchenko2022-01-062-0/+17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch rolls back some of the changes introduced by commit 121f2faca2c0a "xen/balloon: rename alloc/free_xenballooned_pages" in order to make possible to still allocate xenballooned pages if CONFIG_XEN_UNPOPULATED_ALLOC is enabled. On Arm the unpopulated pages will be allocated on top of extended regions provided by Xen via device-tree (the subsequent patches will add required bits to support unpopulated-alloc feature on Arm). The problem is that extended regions feature has been introduced into Xen quite recently (during 4.16 release cycle). So this effectively means that Linux must only use unpopulated-alloc on Arm if it is running on "new Xen" which advertises these regions. But, it will only be known after parsing the "hypervisor" node at boot time, so before doing that we cannot assume anything. In order to keep working if CONFIG_XEN_UNPOPULATED_ALLOC is enabled and the extended regions are not advertised (Linux is running on "old Xen", etc) we need the fallback to alloc_xenballooned_pages(). This way we wouldn't reduce the amount of memory usable (wasting RAM pages) for any of the external mappings anymore (and eliminate XSA-300) with "new Xen", but would be still functional ballooning out RAM pages with "old Xen". Also rename alloc(free)_xenballooned_pages to xen_alloc(free)_ballooned_pages and make xen_alloc(free)_unpopulated_pages static inline in xen.h if CONFIG_XEN_UNPOPULATED_ALLOC is disabled. Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com> Reviewed-by: Stefano Stabellini <sstabellini@kernel.org> Link: https://lore.kernel.org/r/1639080336-26573-4-git-send-email-olekstysh@gmail.com Signed-off-by: Juergen Gross <jgross@suse.com>
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-06 02:00:33 +0000