Subject: [PATCH v2 07/11] powerpc/kvm/e500: Applies counting method to monitor lockless pgtbl walks

From: Leonardo Bras <[email-masked]>
Date: Fri, 20 Sep 2019 16:50:43 -0300

Applies the counting-based method for monitoring lockless pgtable walks on
kvmppc_e500_shadow_map().

Signed-off-by: Leonardo Bras <[email-masked]>
---
 arch/powerpc/kvm/e500_mmu_host.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/powerpc/kvm/e500_mmu_host.c b/arch/powerpc/kvm/e500_mmu_host.c
index 321db0fdb9db..a1b8bfe20bc8 100644
--- a/arch/powerpc/kvm/e500_mmu_host.c
+++ b/arch/powerpc/kvm/e500_mmu_host.c
@@ -473,6 +473,7 @@ static inline int kvmppc_e500_shadow_map(struct kvmppc_vcpu_e500 *vcpu_e500,
 	 * We are holding kvm->mmu_lock so a notifier invalidate
 	 * can't run hence pfn won't change.
 	 */
+	start_lockless_pgtbl_walk(kvm->mm);
 	local_irq_save(flags);
 	ptep = find_linux_pte(pgdir, hva, NULL, NULL);
 	if (ptep) {
@@ -484,12 +485,15 @@ static inline int kvmppc_e500_shadow_map(struct kvmppc_vcpu_e500 *vcpu_e500,
 			local_irq_restore(flags);
 		} else {
 			local_irq_restore(flags);
+			end_lockless_pgtbl_walk(kvm->mm);
 			pr_err_ratelimited("%s: pte not present: gfn %lx,pfn %lx\n",
 					   __func__, (long)gfn, pfn);
 			ret = -EINVAL;
 			goto out;
 		}
 	}
+	end_lockless_pgtbl_walk(kvm->mm);
+
 	kvmppc_e500_ref_setup(ref, gtlbe, pfn, wimg);
 
 	kvmppc_e500_setup_stlbe(&vcpu_e500->vcpu, gtlbe, tsize,
-- 
2.20.1