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

Overview

In the Linux kernel, the following vulnerability has been resolved:

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.

Affected

• Linux >= db8b7e97d6137a28b2bfc07e591d54da268f0c36 < a29c5d2dd2ef9a8617a9a6d5585696d5f149cd98
• Linux >= db8b7e97d6137a28b2bfc07e591d54da268f0c36 < c525772c304c971b0d3a1f2898dedbae653efe90
• Linux >= db8b7e97d6137a28b2bfc07e591d54da268f0c36 < 71acbea44e78665ea90e3c310fca6bbdcc0252db
• Linux >= db8b7e97d6137a28b2bfc07e591d54da268f0c36 < 8ae12ccaec6ec74945d8c1ef39f2c1b8df779abc
• Linux 6.5

Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.