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KVM: x86/mmu: Store the address space ID in the TDP iterator

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Store the address space ID in the TDP iterator so that it can be
retrieved without having to bounce through the root shadow page.  This
streamlines the code and fixes a Sparse warning about not properly using
rcu_dereference() when grabbing the ID from the root on the fly.

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Ben Gardon <bgardon@google.com>
Message-Id: <20210315233803.2706477-5-bgardon@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Sean Christopherson 2021-03-15 16:38:03 -07:00 committed by Paolo Bonzini
parent b601c3bc9d
commit 08889894cc
4 changed files with 13 additions and 24 deletions
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5
arch/x86/kvm/mmu/mmu_internal.h
View File

@ -78,6 +78,11 @@ static inline struct kvm_mmu_page *sptep_to_sp(u64 *sptep)
return to_shadow_page(__pa(sptep));
}
static inline int kvm_mmu_page_as_id(struct kvm_mmu_page *sp)
{
return sp->role.smm ? 1 : 0;
}
static inline bool kvm_vcpu_ad_need_write_protect(struct kvm_vcpu *vcpu)
{
/*

6
arch/x86/kvm/mmu/tdp_iter.c
View File

@ -49,6 +49,7 @@ void tdp_iter_start(struct tdp_iter *iter, u64 *root_pt, int root_level,
iter->root_level = root_level;
iter->min_level = min_level;
iter->pt_path[iter->root_level - 1] = (tdp_ptep_t)root_pt;
iter->as_id = kvm_mmu_page_as_id(sptep_to_sp(root_pt));
tdp_iter_restart(iter);
}
@ -169,8 +170,3 @@ void tdp_iter_next(struct tdp_iter *iter)
iter->valid = false;
}
tdp_ptep_t tdp_iter_root_pt(struct tdp_iter *iter)
{
return iter->pt_path[iter->root_level - 1];
}

3
arch/x86/kvm/mmu/tdp_iter.h
View File

@ -36,6 +36,8 @@ struct tdp_iter {
int min_level;
/* The iterator's current level within the paging structure */
int level;
/* The address space ID, i.e. SMM vs. regular. */
int as_id;
/* A snapshot of the value at sptep */
u64 old_spte;
/*
@ -62,7 +64,6 @@ tdp_ptep_t spte_to_child_pt(u64 pte, int level);
void tdp_iter_start(struct tdp_iter *iter, u64 *root_pt, int root_level,
int min_level, gfn_t next_last_level_gfn);
void tdp_iter_next(struct tdp_iter *iter);
tdp_ptep_t tdp_iter_root_pt(struct tdp_iter *iter);
void tdp_iter_restart(struct tdp_iter *iter);
#endif /* __KVM_X86_MMU_TDP_ITER_H */

23
arch/x86/kvm/mmu/tdp_mmu.c
View File

@ -203,11 +203,6 @@ static void handle_changed_spte(struct kvm *kvm, int as_id, gfn_t gfn,
u64 old_spte, u64 new_spte, int level,
bool shared);
static int kvm_mmu_page_as_id(struct kvm_mmu_page *sp)
{
return sp->role.smm ? 1 : 0;
}
static void handle_changed_spte_acc_track(u64 old_spte, u64 new_spte, int level)
{
bool pfn_changed = spte_to_pfn(old_spte) != spte_to_pfn(new_spte);
@ -497,10 +492,6 @@ static inline bool tdp_mmu_set_spte_atomic(struct kvm *kvm,
struct tdp_iter *iter,
u64 new_spte)
{
u64 *root_pt = tdp_iter_root_pt(iter);
struct kvm_mmu_page *root = sptep_to_sp(root_pt);
int as_id = kvm_mmu_page_as_id(root);
lockdep_assert_held_read(&kvm->mmu_lock);
/*
@ -514,8 +505,8 @@ static inline bool tdp_mmu_set_spte_atomic(struct kvm *kvm,
new_spte) != iter->old_spte)
return false;
handle_changed_spte(kvm, as_id, iter->gfn, iter->old_spte, new_spte,
iter->level, true);
handle_changed_spte(kvm, iter->as_id, iter->gfn, iter->old_spte,
new_spte, iter->level, true);
return true;
}
@ -569,10 +560,6 @@ 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)
{
tdp_ptep_t root_pt = tdp_iter_root_pt(iter);
struct kvm_mmu_page *root = sptep_to_sp(root_pt);
int as_id = kvm_mmu_page_as_id(root);
lockdep_assert_held_write(&kvm->mmu_lock);
/*
@ -586,13 +573,13 @@ static inline void __tdp_mmu_set_spte(struct kvm *kvm, struct tdp_iter *iter,
WRITE_ONCE(*rcu_dereference(iter->sptep), new_spte);
__handle_changed_spte(kvm, as_id, iter->gfn, iter->old_spte, new_spte,
iter->level, false);
__handle_changed_spte(kvm, iter->as_id, iter->gfn, iter->old_spte,
new_spte, iter->level, false);
if (record_acc_track)
handle_changed_spte_acc_track(iter->old_spte, new_spte,
iter->level);
if (record_dirty_log)
handle_changed_spte_dirty_log(kvm, as_id, iter->gfn,
handle_changed_spte_dirty_log(kvm, iter->as_id, iter->gfn,
iter->old_spte, new_spte,
iter->level);
}