kvm: mmu: Used range based flushing in slot_handle_level_range

Ben Gardon · bonzini · commit f285c633cb6d · 2019-03-28T17:28:57.000+01:00
Replace kvm_flush_remote_tlbs with kvm_flush_remote_tlbs_with_address
in slot_handle_level_range. When range based flushes are not enabled
kvm_flush_remote_tlbs_with_address falls back to kvm_flush_remote_tlbs.

This changes the behavior of many functions that indirectly use
slot_handle_level_range, iff the range based flushes are enabled. The
only potential problem I see with this is that kvm-&gt;tlbs_dirty will be
cleared less often, however the only caller of slot_handle_level_range that
checks tlbs_dirty is kvm_mmu_notifier_invalidate_range_start which
checks it and does a kvm_flush_remote_tlbs after calling
kvm_unmap_hva_range anyway.

Tested: Ran all kvm-unit-tests on a Intel Haswell machine with and
	without this patch. The patch introduced no new failures.

Signed-off-by: Ben Gardon &lt;bgardon@google.com&gt;
Signed-off-by: Paolo Bonzini &lt;pbonzini@redhat.com&gt;
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
@@ -5526,15 +5526,18 @@ slot_handle_level_range(struct kvm *kvm, struct kvm_memory_slot *memslot,
 
 		if (need_resched() || spin_needbreak(&kvm->mmu_lock)) {
 			if (flush && lock_flush_tlb) {
-				kvm_flush_remote_tlbs(kvm);
+				kvm_flush_remote_tlbs_with_address(kvm,
+						start_gfn,
+						iterator.gfn - start_gfn + 1);
 				flush = false;
 			}
 			cond_resched_lock(&kvm->mmu_lock);
 		}
 	}
 
 	if (flush && lock_flush_tlb) {
-		kvm_flush_remote_tlbs(kvm);
+		kvm_flush_remote_tlbs_with_address(kvm, start_gfn,
+						   end_gfn - start_gfn + 1);
 		flush = false;
 	}
 

Original file line number	Diff line number	Diff line change
`@@ -5526,15 +5526,18 @@ slot_handle_level_range(struct kvm kvm, struct kvm_memory_slot memslot,`
`5526`	`5526`
`5527`	`5527`	`if (need_resched() \|\| spin_needbreak(&kvm->mmu_lock)) {`
`5528`	`5528`	`if (flush && lock_flush_tlb) {`
`5529`		`- kvm_flush_remote_tlbs(kvm);`
	`5529`	`+ kvm_flush_remote_tlbs_with_address(kvm,`
	`5530`	`+ start_gfn,`
	`5531`	`+ iterator.gfn - start_gfn + 1);`
`5530`	`5532`	`flush = false;`
`5531`	`5533`	`}`
`5532`	`5534`	`cond_resched_lock(&kvm->mmu_lock);`
`5533`	`5535`	`}`
`5534`	`5536`	`}`
`5535`	`5537`
`5536`	`5538`	`if (flush && lock_flush_tlb) {`
`5537`		`- kvm_flush_remote_tlbs(kvm);`
	`5539`	`+ kvm_flush_remote_tlbs_with_address(kvm, start_gfn,`
	`5540`	`+ end_gfn - start_gfn + 1);`
`5538`	`5541`	`flush = false;`
`5539`	`5542`	`}`
`5540`	`5543`