On Thu, Mar 03, 2022, Paolo Bonzini wrote:
> From: Sean Christopherson <seanjc@xxxxxxxxxx>
>
> When yielding in the TDP MMU iterator, service any pending TLB flush
> before dropping RCU protections in anticipation of using the caller's RCU
> "lock" as a proxy for vCPUs in the guest.
>
> Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
> Reviewed-by: Ben Gardon <bgardon@xxxxxxxxxx>
> Message-Id: <20220226001546.360188-19-seanjc@xxxxxxxxxx>
> Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Reviewed-by: Mingwei Zhang <mizhang@xxxxxxxxxx>
> ---
> arch/x86/kvm/mmu/tdp_mmu.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c
> index c71debdbc732..3a866fcb5ea9 100644
> --- a/arch/x86/kvm/mmu/tdp_mmu.c
> +++ b/arch/x86/kvm/mmu/tdp_mmu.c
> @@ -716,11 +716,11 @@ static inline bool __must_check tdp_mmu_iter_cond_resched(struct kvm *kvm,
> return false;
>
> if (need_resched() || rwlock_needbreak(&kvm->mmu_lock)) {
> - rcu_read_unlock();
> -
> if (flush)
> kvm_flush_remote_tlbs(kvm);
>
> + rcu_read_unlock();
> +
> if (shared)
> cond_resched_rwlock_read(&kvm->mmu_lock);
> else
> --
> 2.31.1
>
>
