[PATCH 21/28] KVM: x86/mmu: Add TDP MMU helper to zap a root

Sean Christopherson
2021-11-20T04:52:05Z

Add a small wrapper to handle zapping a specific root. For now, it's
little more than syntactic sugar, but in the future it will become a
unique flow with rules specific to zapping an unreachable root.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@google.com>
---
arch/x86/kvm/mmu/tdp_mmu.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c
index 9449cb5baf0b..31fb622249e5 100644
--- a/arch/x86/kvm/mmu/tdp_mmu.c
+++ b/arch/x86/kvm/mmu/tdp_mmu.c
@@ -79,11 +79,18 @@ static void tdp_mmu_free_sp_rcu_callback(struct rcu_head *head)
tdp_mmu_free_sp(sp);
}

+static bool tdp_mmu_zap_root(struct kvm *kvm, struct kvm_mmu_page *root,
+ bool shared)
+{
+ return zap_gfn_range(kvm, root, 0, -1ull, true, false, shared);
+}
+
/*
* Note, putting a root might sleep, i.e. the caller must have IRQs enabled and
* must not explicitly disable preemption (it will be disabled by virtue of
* holding mmu_lock, hence the lack of a might_sleep()).
*/
+
void kvm_tdp_mmu_put_root(struct kvm *kvm, struct kvm_mmu_page *root,
bool shared)
{
@@ -118,7 +125,7 @@ void kvm_tdp_mmu_put_root(struct kvm *kvm, struct kvm_mmu_page *root,
* should have been zapped by kvm_tdp_mmu_zap_invalidated_roots(), and
* inserting new SPTEs under an invalid root is a KVM bug.
*/
- if (zap_gfn_range(kvm, root, 0, -1ull, true, false, shared))
+ if (tdp_mmu_zap_root(kvm, root, shared))
WARN_ON_ONCE(root->role.invalid);

call_rcu(&root->rcu_head, tdp_mmu_free_sp_rcu_callback);
@@ -923,7 +930,7 @@ void kvm_tdp_mmu_zap_invalidated_roots(struct kvm *kvm,
* will still flush on yield, but that's a minor performance
* blip and not a functional issue.
*/
- (void)zap_gfn_range(kvm, root, 0, -1ull, true, false, true);
+ (void)tdp_mmu_zap_root(kvm, root, true);
kvm_tdp_mmu_put_root(kvm, root, true);
}
}
--
2.34.0.rc2.393.gf8c9666880-goog