The following commit has been merged into the x86/entry branch of tip: Commit-ID: f3020b8891b890b48d9e1a83241e3cce518427c1 Gitweb: https://git.kernel.org/tip/f3020b8891b890b48d9e1a83241e3cce518427c1 Author: Thomas Gleixner <tglx@xxxxxxxxxxxxx> AuthorDate: Thu, 30 Jul 2020 09:19:01 +02:00 Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx> CommitterDate: Thu, 30 Jul 2020 12:31:47 +02:00 x86/kvm: Use __xfer_to_guest_mode_work_pending() in kvm_run_vcpu() The comments explicitely explain that the work flags check and handling in kvm_run_vcpu() is done with preemption and interrupts enabled as KVM invokes the check again right before entering guest mode with interrupts disabled which guarantees that the work flags are observed and handled before VMENTER. Nevertheless the flag pending check in kvm_run_vcpu() uses the helper variant which requires interrupts to be disabled triggering an instant lockdep splat. This was caught in testing before and then not fixed up in the patch before applying. :( Use the relaxed and intentionally racy __xfer_to_guest_mode_work_pending() instead. Fixes: 72c3c0fe54a3 ("x86/kvm: Use generic xfer to guest work function") Reported-by: Qian Cai <cai@xxxxxx> writes: Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Link: https://lkml.kernel.org/r/87bljxa2sa.fsf@xxxxxxxxxxxxxxxxxxxxxxx --- arch/x86/kvm/x86.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 82d4a9e..5325972 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -8682,7 +8682,7 @@ static int vcpu_run(struct kvm_vcpu *vcpu) break; } - if (xfer_to_guest_mode_work_pending()) { + if (__xfer_to_guest_mode_work_pending()) { srcu_read_unlock(&kvm->srcu, vcpu->srcu_idx); r = xfer_to_guest_mode_handle_work(vcpu); if (r)
![]() |