KVM: x86/mmu: Conditionally resched when retrying gPTE walk on A/D update failure

Conditionally reschedule when retrying a guest PTE walk because the CMPXCHG
to update A/D bits failed, e.g. because a different task/vCPU modified the
relevant gPTEs.  On kernels without involuntary preemption of some kind, a
misbehaving guest can "capture" a pCPU effectively indefinitely and trigger
soft lockups by continuously modifying its gPTEs such that the result of
the walk is remains valid.

Fixes: b3e4e63fd9ee ("KVM: MMU: Use cmpxchg for pte updates on walk_addr()")
Cc: stable@vger.kernel.org
Reported-by: Stefan Teodorescu <fane@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-ID: <20261022015903.282261-1-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

0 files changed, 0 insertions, 0 deletions