RISC-V: KVM: Serialize IMSIC attributes with vCPU migration

KVM device ioctls are not serialized against KVM_RUN. As a result,
kvm_riscv_aia_imsic_rw_attr() can snapshot the physical CPU and HGEI of
an IMSIC VS-file before a concurrent vCPU migration releases it.

The HGEI can then be allocated to another vCPU before imsic_vsfile_rw()
uses the stale tuple. A GET or SET attribute may consequently access the
new owner's interrupt file.

Serialize the entire IMSIC attribute operation with the target vCPU
mutex. This prevents the VS-file from being migrated and recycled until
the attribute access completes. Acquire the mutex killably so that the
device ioctl remains interruptible while waiting for KVM_RUN to finish.

Fixes: db8b7e97d613 ("RISC-V: KVM: Add in-kernel virtualization of AIA IMSIC")
Cc: stable@vger.kernel.org
Signed-off-by: Xie Bo <xb@ultrarisc.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Link: https://lore.kernel.org/r/20260810-imsic-attr-race-v2-1-00ed95ad321e@ultrarisc.com
Signed-off-by: Anup Patel <anup@brainfault.org>

0 files changed, 0 insertions, 0 deletions