Combine the back-to-back if-statements for synchronizing children when
linking a new indirect shadow page in order to decrease the indentation,
and to make it easier to "see" the logic in its entirety.
No functional change intended.
Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
arch/x86/kvm/mmu/paging_tmpl.h | 40 ++++++++++++++++------------------
1 file changed, 19 insertions(+), 21 deletions(-)
diff --git a/arch/x86/kvm/mmu/paging_tmpl.h b/arch/x86/kvm/mmu/paging_tmpl.h
index 69941cebb3a8..0e97e080a997 100644
--- a/arch/x86/kvm/mmu/paging_tmpl.h
+++ b/arch/x86/kvm/mmu/paging_tmpl.h
@@ -674,27 +674,25 @@ static int FNAME(fetch)(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault,
sp = kvm_mmu_get_child_sp(vcpu, it.sptep, table_gfn,
false, access);
- if (sp != ERR_PTR(-EEXIST)) {
- /*
- * We must synchronize the pagetable before linking it
- * because the guest doesn't need to flush tlb when
- * the gpte is changed from non-present to present.
- * Otherwise, the guest may use the wrong mapping.
- *
- * For PG_LEVEL_4K, kvm_mmu_get_page() has already
- * synchronized it transiently via kvm_sync_page().
- *
- * For higher level pagetable, we synchronize it via
- * the slower mmu_sync_children(). If it needs to
- * break, some progress has been made; return
- * RET_PF_RETRY and retry on the next #PF.
- * KVM_REQ_MMU_SYNC is not necessary but it
- * expedites the process.
- */
- if (sp->unsync_children &&
- mmu_sync_children(vcpu, sp, false))
- return RET_PF_RETRY;
- }
+ /*
+ * Synchronize the new page before linking it, as the CPU (KVM)
+ * is architecturally disallowed from inserting non-present
+ * entries into the TLB, i.e. the guest isn't required to flush
+ * the TLB when changing the gPTE from non-present to present.
+ *
+ * For PG_LEVEL_4K, kvm_mmu_find_shadow_page() has already
+ * synchronized the page via kvm_sync_page().
+ *
+ * For higher level pages, which cannot be unsync themselves
+ * but can have unsync children, synchronize via the slower
+ * mmu_sync_children(). If KVM needs to drop mmu_lock due to
+ * contention or to reschedule, instruct the caller to retry
+ * the #PF (mmu_sync_children() ensures forward progress will
+ * be made).
+ */
+ if (sp != ERR_PTR(-EEXIST) && sp->unsync_children &&
+ mmu_sync_children(vcpu, sp, false))
+ return RET_PF_RETRY;
/*
* Verify that the gpte in the page we've just write
--
2.46.0.rc2.264.g509ed76dc8-goog
