android_kernel_motorola_sm6375/virt/kvm
Repository files (latest commit first)
Filename Latest commit message Latest commit date
David Matlack a1c03f11cc KVM: Prevent module exit until all VMs are freed
commit 5f6de5cbebee925a612856fce6f9182bb3eee0db upstream.

Tie the lifetime the KVM module to the lifetime of each VM via
kvm.users_count. This way anything that grabs a reference to the VM via
kvm_get_kvm() cannot accidentally outlive the KVM module.

Prior to this commit, the lifetime of the KVM module was tied to the
lifetime of /dev/kvm file descriptors, VM file descriptors, and vCPU
file descriptors by their respective file_operations "owner" field.
This approach is insufficient because references grabbed via
kvm_get_kvm() do not prevent closing any of the aforementioned file
descriptors.

This fixes a long standing theoretical bug in KVM that at least affects
async page faults. kvm_setup_async_pf() grabs a reference via
kvm_get_kvm(), and drops it in an asynchronous work callback. Nothing
prevents the VM file descriptor from being closed and the KVM module
from being unloaded before this callback runs.

Fixes: af585b921e ("KVM: Halt vcpu if page it tries to access is swapped out")
Fixes: 3d3aab1b97 ("KVM: set owner of cpu and vm file operations")
Cc: stable@vger.kernel.org
Suggested-by: Ben Gardon <bgardon@google.com>
[ Based on a patch from Ben implemented for Google's kernel. ]
Signed-off-by: David Matlack <dmatlack@google.com>
Message-Id: <20220303183328.1499189-2-dmatlack@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-04-15 14:18:27 +02:00
..
arm KVM: arm64: Allow SMCCC_ARCH_WORKAROUND_3 to be discovered and migrated 2022-03-19 13:40:15 +01:00
async_pf.c KVM: x86: Use gpa_t for cr2/gpa to fix TDP support on 32-bit KVM 2020-02-11 04:35:53 -08:00
async_pf.h
coalesced_mmio.c KVM: mmio: Fix use-after-free Read in kvm_vm_ioctl_unregister_coalesced_mmio 2021-07-20 16:10:40 +02:00
coalesced_mmio.h
eventfd.c
irqchip.c
Kconfig
kvm_main.c KVM: Prevent module exit until all VMs are freed 2022-04-15 14:18:27 +02:00
vfio.c
vfio.h