kernel.git/drivers/xen/privcmd.c, branch linux-4.19.y

xen/privcmd: Fix a possible warning in privcmd_ioctl_mmap_resource()

2023-01-18T10:30:07Z

[ Upstream commit 8b997b2bb2c53b76a6db6c195930e9ab8e4b0c79 ] As 'kdata.num' is user-controlled data, if user tries to allocate memory larger than(>=) MAX_ORDER, then kcalloc() will fail, it creates a stack trace and messes up dmesg with a warning. Call trace: -> privcmd_ioctl --> privcmd_ioctl_mmap_resource Add __GFP_NOWARN in order to avoid too large allocation warning. This is detected by static analysis using smatch. Fixes: 3ad0876554ca ("xen/privcmd: add IOCTL_PRIVCMD_MMAP_RESOURCE") Signed-off-by: Harshit Mogalapalli Reviewed-by: Juergen Gross Link: https://lore.kernel.org/r/20221126050745.778967-1-harshit.m.mogalapalli@oracle.com Signed-off-by: Juergen Gross Signed-off-by: Sasha Levin

xen/privcmd: fix error handling in mmap-resource processing

2021-10-13T08:10:50Z

commit e11423d6721dd63b23fb41ade5e8d0b448b17780 upstream. xen_pfn_t is the same size as int only on 32-bit builds (and not even on Arm32). Hence pfns[] can't be used directly to read individual error values returned from xen_remap_domain_mfn_array(); every other error indicator would be skipped/ignored on 64-bit. Fixes: 3ad0876554ca ("xen/privcmd: add IOCTL_PRIVCMD_MMAP_RESOURCE") Cc: stable@vger.kernel.org Signed-off-by: Jan Beulich Reviewed-by: Boris Ostrovsky Signed-off-by: Greg Kroah-Hartman Link: https://lore.kernel.org/r/aa6d6a67-6889-338a-a910-51e889f792d5@suse.com Signed-off-by: Juergen Gross

xen/privcmd: allow fetching resource sizes

2021-02-03T22:23:24Z

commit ef3a575baf53571dc405ee4028e26f50856898e7 upstream. Allow issuing an IOCTL_PRIVCMD_MMAP_RESOURCE ioctl with num = 0 and addr = 0 in order to fetch the size of a specific resource. Add a shortcut to the default map resource path, since fetching the size requires no address to be passed in, and thus no VMA to setup. This is missing from the initial implementation, and causes issues when mapping resources that don't have fixed or known sizes. Signed-off-by: Roger Pau Monné Reviewed-by: Juergen Gross Tested-by: Andrew Cooper Cc: stable@vger.kernel.org # >= 4.18 Link: https://lore.kernel.org/r/20210112115358.23346-1-roger.pau@citrix.com Signed-off-by: Juergen Gross Signed-off-by: Greg Kroah-Hartman

xen: add new hypercall buffer mapping device

2018-06-22T06:26:42Z

For passing arbitrary data from user land to the Xen hypervisor the Xen tools today are using mlock()ed buffers. Unfortunately the kernel might change access rights of such buffers for brief periods of time e.g. for page migration or compaction, leading to access faults in the hypervisor, as the hypervisor can't use the locks of the kernel. In order to solve this problem add a new device node to the Xen privcmd driver to easily allocate hypercall buffers via mmap(). The memory is allocated in the kernel and just mapped into user space. Marked as VM_IO the user mapping will not be subject to page migration et al. Signed-off-by: Juergen Gross Reviewed-by: Boris Ostrovsky Signed-off-by: Juergen Gross

xen/privcmd: add IOCTL_PRIVCMD_MMAP_RESOURCE

2018-05-14T13:25:37Z

My recent Xen patch series introduces a new HYPERVISOR_memory_op to support direct priv-mapping of certain guest resources (such as ioreq pages, used by emulators) by a tools domain, rather than having to access such resources via the guest P2M. This patch adds the necessary infrastructure to the privcmd driver and Xen MMU code to support direct resource mapping. NOTE: The adjustment in the MMU code is partially cosmetic. Xen will now allow a PV tools domain to map guest pages either by GFN or MFN, thus the term 'mfn' has been swapped for 'pfn' in the lower layers of the remap code. Signed-off-by: Paul Durrant Reviewed-by: Boris Ostrovsky Signed-off-by: Juergen Gross

xen: Change return type to vm_fault_t

2018-05-14T12:41:34Z

Use new return type vm_fault_t for fault handler in struct vm_operations_struct. Signed-off-by: Souptick Joarder Reviewed-by: Matthew Wilcox Reviewed-by: Juergen Gross Signed-off-by: Juergen Gross

xen/privcmd: remove unused variable pageidx

2017-11-08T14:15:28Z

Variable pageidx is assigned a value but it is never read, hence it is redundant and can be removed. Cleans up clang warning: drivers/xen/privcmd.c:199:2: warning: Value stored to 'pageidx' is never read Signed-off-by: Colin Ian King Reviewed-by: Juergen Gross Signed-off-by: Boris Ostrovsky

xen/privcmd: Support correctly 64KB page granularity when mapping memory

2017-06-07T09:23:14Z

Commit 5995a68 "xen/privcmd: Add support for Linux 64KB page granularity" did not go far enough to support 64KB in mmap_batch_fn. The variable 'nr' is the number of 4KB chunk to map. However, when Linux is using 64KB page granularity the array of pages (vma->vm_private_data) contain one page per 64KB. Fix it by incrementing st->index correctly. Furthermore, st->va is not correctly incremented as PAGE_SIZE != XEN_PAGE_SIZE. Fixes: 5995a68 ("xen/privcmd: Add support for Linux 64KB page granularity") CC: stable@vger.kernel.org Reported-by: Feng Kan Signed-off-by: Julien Grall Reviewed-by: Boris Ostrovsky Signed-off-by: Juergen Gross

mm, fs: reduce fault, page_mkwrite, and pfn_mkwrite to take only vmf

2017-02-25T01:46:54Z

->fault(), ->page_mkwrite(), and ->pfn_mkwrite() calls do not need to take a vma and vmf parameter when the vma already resides in vmf. Remove the vma parameter to simplify things. [arnd@arndb.de: fix ARM build] Link: http://lkml.kernel.org/r/20170125223558.1451224-1-arnd@arndb.de Link: http://lkml.kernel.org/r/148521301778.19116.10840599906674778980.stgit@djiang5-desk3.ch.intel.com Signed-off-by: Dave Jiang Signed-off-by: Arnd Bergmann Reviewed-by: Ross Zwisler Cc: Theodore Ts'o Cc: Darrick J. Wong Cc: Matthew Wilcox Cc: Dave Hansen Cc: Christoph Hellwig Cc: Jan Kara Cc: Dan Williams Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

xen/privcmd: add IOCTL_PRIVCMD_RESTRICT

2017-02-14T20:14:59Z

The purpose if this ioctl is to allow a user of privcmd to restrict its operation such that it will no longer service arbitrary hypercalls via IOCTL_PRIVCMD_HYPERCALL, and will check for a matching domid when servicing IOCTL_PRIVCMD_DM_OP or IOCTL_PRIVCMD_MMAP*. The aim of this is to limit the attack surface for a compromised device model. Signed-off-by: Paul Durrant Signed-off-by: Boris Ostrovsky