[PATCH V4 7/15] KVM/MMU: Flush tlb directly in the kvm_zap_gfn_range()

From: lantianyu1986
Date: Sat Oct 13 2018 - 10:55:10 EST


From: Lan Tianyu <Tianyu.Lan@xxxxxxxxxxxxx>

Originally, flush tlb is done by slot_handle_level_range(). This patch
is to flush tlb directly in the kvm_zap_gfn_range() when range
flush is available.

Signed-off-by: Lan Tianyu <Tianyu.Lan@xxxxxxxxxxxxx>
---
arch/x86/kvm/mmu.c | 16 +++++++++++++---
1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index f3742ff4ec18..c4f7679f12c3 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -5647,6 +5647,7 @@ void kvm_zap_gfn_range(struct kvm *kvm, gfn_t gfn_start, gfn_t gfn_end)
{
struct kvm_memslots *slots;
struct kvm_memory_slot *memslot;
+ bool flush = false;
int i;

spin_lock(&kvm->mmu_lock);
@@ -5654,18 +5655,27 @@ void kvm_zap_gfn_range(struct kvm *kvm, gfn_t gfn_start, gfn_t gfn_end)
slots = __kvm_memslots(kvm, i);
kvm_for_each_memslot(memslot, slots) {
gfn_t start, end;
+ bool flush_tlb = true;

start = max(gfn_start, memslot->base_gfn);
end = min(gfn_end, memslot->base_gfn + memslot->npages);
if (start >= end)
continue;

- slot_handle_level_range(kvm, memslot, kvm_zap_rmapp,
- PT_PAGE_TABLE_LEVEL, PT_MAX_HUGEPAGE_LEVEL,
- start, end - 1, true);
+ if (kvm_available_flush_tlb_with_range())
+ flush_tlb = false;
+
+ flush = slot_handle_level_range(kvm, memslot,
+ kvm_zap_rmapp, PT_PAGE_TABLE_LEVEL,
+ PT_MAX_HUGEPAGE_LEVEL, start,
+ end - 1, flush_tlb);
}
}

+ if (flush && kvm_available_flush_tlb_with_range())
+ kvm_flush_remote_tlbs_with_address(kvm, gfn_start,
+ gfn_end - gfn_start + 1);
+
spin_unlock(&kvm->mmu_lock);
}

--
2.14.4