linux/virt/kvm
Sean Christopherson 087e15206d KVM: Set file_operations.owner appropriately for all such structures
Set .owner for all KVM-owned filed types so that the KVM module is pinned
until any files with callbacks back into KVM are completely freed.  Using
"struct kvm" as a proxy for the module, i.e. keeping KVM-the-module alive
while there are active VMs, doesn't provide full protection.

Userspace can invoke delete_module() the instant the last reference to KVM
is put.  If KVM itself puts the last reference, e.g. via kvm_destroy_vm(),
then it's possible for KVM to be preempted and deleted/unloaded before KVM
fully exits, e.g. when the task running kvm_destroy_vm() is scheduled back
in, it will jump to a code page that is no longer mapped.

Note, file types that can call into sub-module code, e.g. kvm-intel.ko or
kvm-amd.ko on x86, must use the module pointer passed to kvm_init(), not
THIS_MODULE (which points at kvm.ko).  KVM assumes that if /dev/kvm is
reachable, e.g. VMs are active, then the vendor module is loaded.

To reduce the probability of forgetting to set .owner entirely, use
THIS_MODULE for stats files where KVM does not call back into vendor code.

This reverts commit 70375c2d8f, and fixes
several other file types that have been buggy since their introduction.

Fixes: 70375c2d8f ("Revert "KVM: set owner of cpu and vm file operations"")
Fixes: 3bcd0662d6 ("KVM: X86: Introduce mmu_rmaps_stat per-vm debugfs file")
Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Link: https://lore.kernel.org/all/20231010003746.GN800259@ZenIV
Link: https://lore.kernel.org/r/20231018204624.1905300-2-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-12-01 08:12:17 -08:00
..
async_pf.c mm/gup: remove vmas parameter from get_user_pages_remote() 2023-06-09 16:25:26 -07:00
async_pf.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 504 2019-06-19 17:09:56 +02:00
binary_stats.c KVM: stats: remove dead stores 2021-08-13 03:35:15 -04:00
coalesced_mmio.c KVM: destruct kvm_io_device while unregistering it from kvm_io_bus 2023-06-13 14:18:09 -07:00
coalesced_mmio.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
dirty_ring.c KVM: Support dirty ring in conjunction with bitmap 2022-11-10 13:11:58 +00:00
eventfd.c kvm/eventfd: use list_for_each_entry when deassign ioeventfd 2023-06-13 14:25:39 -07:00
irqchip.c KVM: replace direct irq.h inclusion 2022-11-09 12:31:37 -05:00
Kconfig KVM: Remove CONFIG_HAVE_KVM_ARCH_TLB_FLUSH_ALL 2023-08-17 09:35:14 +01:00
kvm_main.c KVM: Set file_operations.owner appropriately for all such structures 2023-12-01 08:12:17 -08:00
kvm_mm.h kvm: Remove the unused macro KVM_MMU_READ_{,UN}LOCK() 2022-12-27 06:00:51 -05:00
Makefile.kvm KVM: Reinstate gfn_to_pfn_cache with invalidation support 2022-01-07 10:44:44 -05:00
pfncache.c KVM: Skip unnecessary "unmap" if gpc is already valid during refresh 2022-11-30 19:25:24 +00:00
vfio.c kvm/vfio: avoid bouncing the mutex when adding and deleting groups 2023-08-03 12:01:56 -06:00
vfio.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00