On 11/20/21 00:57, David Matlack wrote:
Derive the page role from the parent shadow page, since the only thing
that changes is the level. This is in preparation for eagerly splitting
large pages during VM-ioctls which does not have access to the vCPU
MMU context.
No functional change intended.
Signed-off-by: David Matlack <dmatlack@xxxxxxxxxx>
---
arch/x86/kvm/mmu/tdp_mmu.c | 43 ++++++++++++++++++++------------------
1 file changed, 23 insertions(+), 20 deletions(-)
diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c
index b70707a7fe87..1a409992a57f 100644
--- a/arch/x86/kvm/mmu/tdp_mmu.c
+++ b/arch/x86/kvm/mmu/tdp_mmu.c
@@ -157,23 +157,8 @@ static struct kvm_mmu_page *tdp_mmu_next_root(struct kvm *kvm,
if (kvm_mmu_page_as_id(_root) != _as_id) { \
} else
-static union kvm_mmu_page_role page_role_for_level(struct kvm_vcpu *vcpu,
- int level)
-{
- union kvm_mmu_page_role role;
-
- role = vcpu->arch.mmu->mmu_role.base;
- role.level = level;
- role.direct = true;
- role.gpte_is_8_bytes = true;
- role.access = ACC_ALL;
- role.ad_disabled = !shadow_accessed_mask;
-
- return role;
-}
-
static struct kvm_mmu_page *alloc_tdp_mmu_page(struct kvm_vcpu *vcpu, gfn_t gfn,
- int level)
+ union kvm_mmu_page_role role)
{
struct kvm_mmu_memory_caches *mmu_caches;
struct kvm_mmu_page *sp;
@@ -184,7 +169,7 @@ static struct kvm_mmu_page *alloc_tdp_mmu_page(struct kvm_vcpu *vcpu, gfn_t gfn,
sp->spt = kvm_mmu_memory_cache_alloc(&mmu_caches->shadow_page_cache);
set_page_private(virt_to_page(sp->spt), (unsigned long)sp);
- sp->role.word = page_role_for_level(vcpu, level).word;
+ sp->role = role;
sp->gfn = gfn;
sp->tdp_mmu_page = true;
@@ -193,6 +178,19 @@ static struct kvm_mmu_page *alloc_tdp_mmu_page(struct kvm_vcpu *vcpu, gfn_t gfn,
return sp;
}
+static struct kvm_mmu_page *alloc_child_tdp_mmu_page(struct kvm_vcpu *vcpu, struct tdp_iter *iter)
+{
+ struct kvm_mmu_page *parent_sp;
+ union kvm_mmu_page_role role;
+
+ parent_sp = sptep_to_sp(rcu_dereference(iter->sptep));
+
+ role = parent_sp->role;
+ role.level--;
+
+ return alloc_tdp_mmu_page(vcpu, iter->gfn, role);
+}
+
hpa_t kvm_tdp_mmu_get_vcpu_root_hpa(struct kvm_vcpu *vcpu)
{
union kvm_mmu_page_role role;
@@ -201,7 +199,12 @@ hpa_t kvm_tdp_mmu_get_vcpu_root_hpa(struct kvm_vcpu *vcpu)
lockdep_assert_held_write(&kvm->mmu_lock);
- role = page_role_for_level(vcpu, vcpu->arch.mmu->shadow_root_level);
+ role = vcpu->arch.mmu->mmu_role.base;
+ role.level = vcpu->arch.mmu->shadow_root_level;
+ role.direct = true;
+ role.gpte_is_8_bytes = true;
+ role.access = ACC_ALL;
+ role.ad_disabled = !shadow_accessed_mask;
I have a similar patch for the old MMU, but it was also replacing
shadow_root_level with shadow_root_role. I'll see if I can adapt it to
the TDP MMU, since the shadow_root_role is obviously the same for both.
Paolo
/* Check for an existing root before allocating a new one. */
for_each_tdp_mmu_root(kvm, root, kvm_mmu_role_as_id(role)) {
@@ -210,7 +213,7 @@ hpa_t kvm_tdp_mmu_get_vcpu_root_hpa(struct kvm_vcpu *vcpu)
goto out;
}
- root = alloc_tdp_mmu_page(vcpu, 0, vcpu->arch.mmu->shadow_root_level);
+ root = alloc_tdp_mmu_page(vcpu, 0, role);
refcount_set(&root->tdp_mmu_root_count, 1);
spin_lock(&kvm->arch.tdp_mmu_pages_lock);
@@ -1028,7 +1031,7 @@ int kvm_tdp_mmu_map(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault)
if (is_removed_spte(iter.old_spte))
break;
- sp = alloc_tdp_mmu_page(vcpu, iter.gfn, iter.level - 1);
+ sp = alloc_child_tdp_mmu_page(vcpu, &iter);
if (!tdp_mmu_install_sp_atomic(vcpu->kvm, &iter, sp, account_nx))
break;
}
