[PATCH 5.10 092/126] KVM: x86/mmu: Add comment on __tdp_mmu_set_spte

Greg Kroah-Hartman
2021-04-05T09:13:31Z

From: Ben Gardon <bgardon@google.com>

[ Upstream commit fe43fa2f407b9d513f7bcf18142e14e1bf1508d6 ]

__tdp_mmu_set_spte is a very important function in the TDP MMU which
already accepts several arguments and will take more in future commits.
To offset this complexity, add a comment to the function describing each
of the arguemnts.

No functional change intended.

Reviewed-by: Peter Feiner <pfeiner@google.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Ben Gardon <bgardon@google.com>
Message-Id: <20210202185734.1680553-3-bgardon@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/x86/kvm/mmu/tdp_mmu.c | 16 ++++++++++++++++
1 file changed, 16 insertions(+)

diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c
index 34ef3e1a0f84..f88404033e0c 100644
--- a/arch/x86/kvm/mmu/tdp_mmu.c
+++ b/arch/x86/kvm/mmu/tdp_mmu.c
@@ -395,6 +395,22 @@ static void handle_changed_spte(struct kvm *kvm, int as_id, gfn_t gfn,
new_spte, level);
}

+/*
+ * __tdp_mmu_set_spte - Set a TDP MMU SPTE and handle the associated bookkeeping
+ * @kvm: kvm instance
+ * @iter: a tdp_iter instance currently on the SPTE that should be set
+ * @new_spte: The value the SPTE should be set to
+ * @record_acc_track: Notify the MM subsystem of changes to the accessed state
+ * of the page. Should be set unless handling an MMU
+ * notifier for access tracking. Leaving record_acc_track
+ * unset in that case prevents page accesses from being
+ * double counted.
+ * @record_dirty_log: Record the page as dirty in the dirty bitmap if
+ * appropriate for the change being made. Should be set
+ * unless performing certain dirty logging operations.
+ * Leaving record_dirty_log unset in that case prevents page
+ * writes from being double counted.
+ */
static inline void __tdp_mmu_set_spte(struct kvm *kvm, struct tdp_iter *iter,
u64 new_spte, bool record_acc_track,
bool record_dirty_log)
--
2.30.1