Sean Christopherson b29125ead0 KVM: Initialize a vCPU's index to '-1' while it's being created ...

Invalidate a vCPU's index immediately after allocating storage for the vCPU
so that KVM doesn't incorrectly treat a vCPU that is the process of being
created as being vCPU0.  This will also allow detecting that a vCPU is in
the process of being created and thus otherwise unreachable, which is
useful for avoiding false positives in lockdep assertions on vcpu->mutex.

Unwind the index back to -1 if inserting the vCPU into the array or adding
the vCPU to the fd table fails, so that kvm_arch_vcpu_destroy() sees the
vCPU as unreachable, i.e. so that teardown logic doesn't hit false positive
lockdep assertions.  Opportunistically add a comment to call out that the
"real" index needs to be set before making the vCPU visible to other tasks.

Note, kvm_wait_for_vcpu_online() naturally does the right thing thanks to
vcpu->vcpu_idx and kvm->online_vcpus being signed values.

Reviewed-by: Philippe Mathieu-Daudé <philmd@oss.qualcomm.com>
Link: https://patch.msgid.link/20260630225619.511632-8-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

2026-07-08 13:41:12 -07:00

..

kvm

KVM: Initialize a vCPU's index to '-1' while it's being created

2026-07-08 13:41:12 -07:00

lib

irqbypass: Require producers to pass in Linux IRQ number during registration

2025-06-20 13:52:41 -07:00

Makefile

treewide: Add SPDX license identifier - Makefile/Kconfig

2019-05-21 10:50:46 +02:00