[PATCH 11/16] KVM: x86/tdp_mmu: Extract root invalid check from tdx_mmu_next_root()

Rick Edgecombe
2024-05-15T01:00:10Z

From: Isaku Yamahata <isaku.yamahata@intel.com>

Extract tdp_mmu_root_match() to check if the root has given types and use
it for the root page table iterator. It checks only_invalid now.

TDX KVM operates on a shared page table only (Shared-EPT), a mirrored page
table only (Secure-EPT), or both based on the operation. KVM MMU notifier
operations only on shared page table. KVM guest_memfd invalidation
operations only on mirrored page table, and so on. Introduce a centralized
matching function instead of open coding matching logic in the iterator.
The next step is to extend the function to check whether the page is shared
or private

Link: https://lore.kernel.org/kvm/ZivazWQw1oCU8VBC@google.com/
Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
---
TDX MMU Part 1:
- New patch
---
arch/x86/kvm/mmu/tdp_mmu.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c
index 810d552e9bf6..a0b7c43e843d 100644
--- a/arch/x86/kvm/mmu/tdp_mmu.c
+++ b/arch/x86/kvm/mmu/tdp_mmu.c
@@ -92,6 +92,14 @@ void kvm_tdp_mmu_put_root(struct kvm *kvm, struct kvm_mmu_page *root)
call_rcu(&root->rcu_head, tdp_mmu_free_sp_rcu_callback);
}

+static bool tdp_mmu_root_match(struct kvm_mmu_page *root, bool only_valid)
+{
+ if (only_valid && root->role.invalid)
+ return false;
+
+ return true;
+}
+
/*
* Returns the next root after @prev_root (or the first root if @prev_root is
* NULL). A reference to the returned root is acquired, and the reference to
@@ -125,7 +133,7 @@ static struct kvm_mmu_page *tdp_mmu_next_root(struct kvm *kvm,
typeof(*next_root), link);

while (next_root) {
- if ((!only_valid || !next_root->role.invalid) &&
+ if (tdp_mmu_root_match(next_root, only_valid) &&
kvm_tdp_mmu_get_root(next_root))
break;

@@ -176,7 +184,7 @@ static struct kvm_mmu_page *tdp_mmu_next_root(struct kvm *kvm,
list_for_each_entry(_root, &_kvm->arch.tdp_mmu_roots, link) \
if (kvm_lockdep_assert_mmu_lock_held(_kvm, false) && \
((_as_id >= 0 && kvm_mmu_page_as_id(_root) != _as_id) || \
- ((_only_valid) && (_root)->role.invalid))) { \
+ !tdp_mmu_root_match((_root), (_only_valid)))) { \
} else

#define for_each_tdp_mmu_root(_kvm, _root, _as_id) \
--
2.34.1