[PATCH 17/18] KVM: x86/mmu: Allow yielding during MMU notifier unmap/zap, if possible
From: Sean Christopherson <seanjc@google.com>
Date: 2021-03-26 02:21:51
Also in:
kvm, kvmarm, linux-mips, lkml
Subsystem:
kernel virtual machine for x86 (kvm/x86), the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Sean Christopherson, Paolo Bonzini, Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
Let the TDP MMU yield when unmapping a range in response to a MMU notification, if yielding is allowed by said notification. There is no reason to disallow yielding in this case, and in theory the range being invalidated could be quite large. Cc: Ben Gardon <redacted> Signed-off-by: Sean Christopherson <seanjc@google.com> --- arch/x86/kvm/mmu/tdp_mmu.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c
index f6a82230baa5..21bb8b68a553 100644
--- a/arch/x86/kvm/mmu/tdp_mmu.c
+++ b/arch/x86/kvm/mmu/tdp_mmu.c@@ -885,7 +885,7 @@ bool kvm_tdp_mmu_unmap_gfn_range(struct kvm *kvm, struct kvm_gfn_range *range, for_each_tdp_mmu_root(kvm, root, range->slot->as_id) flush |= zap_gfn_range(kvm, root, range->start, range->end, - false, flush); + range->may_block, flush); return flush; }
@@ -903,6 +903,10 @@ static __always_inline bool kvm_tdp_mmu_handle_gfn(struct kvm *kvm, rcu_read_lock(); + /* + * Don't support rescheduling, none of the MMU notifiers that funnel + * into this helper allow blocking; it'd be dead, wasteful code. + */ for_each_tdp_mmu_root(kvm, root, range->slot->as_id) { tdp_root_for_each_leaf_pte(iter, root, range->start, range->end) ret |= handler(kvm, &iter, range);
--
2.31.0.291.g576ba9dcdaf-goog
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