[PATCH 1/2] KVM: x86/mmu: Skip tlb flush if it has been done in zap_gfn_range()

From: Hou Wenlong
Date: Wed Nov 17 2021 - 04:20:52 EST


If the parameter flush is set, zap_gfn_range() would flush remote tlb
when yield, then tlb flush is not needed outside. So use the return
value of zap_gfn_range() directly instead of OR on it in
kvm_unmap_gfn_range() and kvm_tdp_mmu_unmap_gfn_range().

Fixes: 3039bcc744980 ("KVM: Move x86's MMU notifier memslot walkers to generic code")
Signed-off-by: Hou Wenlong <houwenlong93@xxxxxxxxxxxxxxxxx>
---
arch/x86/kvm/mmu/mmu.c | 2 +-
arch/x86/kvm/mmu/tdp_mmu.c | 4 ++--
2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 354d2ca92df4..d57319e596a9 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -1582,7 +1582,7 @@ bool kvm_unmap_gfn_range(struct kvm *kvm, struct kvm_gfn_range *range)
flush = kvm_handle_gfn_range(kvm, range, kvm_unmap_rmapp);

if (is_tdp_mmu_enabled(kvm))
- flush |= kvm_tdp_mmu_unmap_gfn_range(kvm, range, flush);
+ flush = kvm_tdp_mmu_unmap_gfn_range(kvm, range, flush);

return flush;
}
diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c
index 7c5dd83e52de..9d03f5b127dc 100644
--- a/arch/x86/kvm/mmu/tdp_mmu.c
+++ b/arch/x86/kvm/mmu/tdp_mmu.c
@@ -1034,8 +1034,8 @@ bool kvm_tdp_mmu_unmap_gfn_range(struct kvm *kvm, struct kvm_gfn_range *range,
struct kvm_mmu_page *root;

for_each_tdp_mmu_root(kvm, root, range->slot->as_id)
- flush |= zap_gfn_range(kvm, root, range->start, range->end,
- range->may_block, flush, false);
+ flush = zap_gfn_range(kvm, root, range->start, range->end,
+ range->may_block, flush, false);

return flush;
}
--
2.31.1