6.15-stable review patch. If anyone has any objections, please let me know.
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From: Yosry Ahmed yosry.ahmed@linux.dev
commit 1bee4838eb3a2c689f23c7170ea66ae87ea7d93a upstream.
When freeing a vCPU and thus its VMCB, clear current_vmcb for all possible CPUs, not just online CPUs, as it's theoretically possible a CPU could go offline and come back online in conjunction with KVM reusing the page for a new VMCB.
Link: https://lore.kernel.org/all/20250320013759.3965869-1-yosry.ahmed@linux.dev Fixes: fd65d3142f73 ("kvm: svm: Ensure an IBPB on all affected CPUs when freeing a vmcb") Cc: stable@vger.kernel.org Cc: Jim Mattson jmattson@google.com Signed-off-by: Yosry Ahmed yosry.ahmed@linux.dev [sean: split to separate patch, write changelog] Signed-off-by: Sean Christopherson seanjc@google.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/x86/kvm/svm/svm.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -1488,7 +1488,7 @@ static void svm_clear_current_vmcb(struc { int i;
- for_each_online_cpu(i) + for_each_possible_cpu(i) cmpxchg(per_cpu_ptr(&svm_data.current_vmcb, i), vmcb, NULL); }