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| author | Paolo Bonzini <pbonzini@redhat.com> | 2022-02-08 17:53:55 -0500 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2022-02-25 08:20:17 -0500 |
| commit | 594bef7931089cbdeaf7d8954d54535c8ddd4b30 (patch) | |
| tree | b872721a995491c9395860c153f0fbe5e59f1b37 /arch/x86/kvm/mmu | |
| parent | b9e5603c2a3accbadfec570ac501a54431a6bdba (diff) | |
| download | linux-594bef7931089cbdeaf7d8954d54535c8ddd4b30.tar.bz2 | |
KVM: x86/mmu: do not consult levels when freeing roots
Right now, PGD caching requires a complicated dance of first computing
the MMU role and passing it to __kvm_mmu_new_pgd(), and then separately calling
kvm_init_mmu().
Part of this is due to kvm_mmu_free_roots using mmu->root_level and
mmu->shadow_root_level to distinguish whether the page table uses a single
root or 4 PAE roots. Because kvm_init_mmu() can overwrite mmu->root_level,
kvm_mmu_free_roots() must be called before kvm_init_mmu().
However, even after kvm_init_mmu() there is a way to detect whether the
page table may hold PAE roots, as root.hpa isn't backed by a shadow when
it points at PAE roots. Using this method results in simpler code, and
is one less obstacle in moving all calls to __kvm_mmu_new_pgd() after the
MMU has been initialized.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/mmu')
| -rw-r--r-- | arch/x86/kvm/mmu/mmu.c | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 5b5933331491..b97ff7601d0a 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -3224,12 +3224,15 @@ void kvm_mmu_free_roots(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu, struct kvm *kvm = vcpu->kvm; int i; LIST_HEAD(invalid_list); - bool free_active_root = roots_to_free & KVM_MMU_ROOT_CURRENT; + bool free_active_root; BUILD_BUG_ON(KVM_MMU_NUM_PREV_ROOTS >= BITS_PER_LONG); /* Before acquiring the MMU lock, see if we need to do any real work. */ - if (!(free_active_root && VALID_PAGE(mmu->root.hpa))) { + free_active_root = (roots_to_free & KVM_MMU_ROOT_CURRENT) + && VALID_PAGE(mmu->root.hpa); + + if (!free_active_root) { for (i = 0; i < KVM_MMU_NUM_PREV_ROOTS; i++) if ((roots_to_free & KVM_MMU_ROOT_PREVIOUS(i)) && VALID_PAGE(mmu->prev_roots[i].hpa)) @@ -3247,8 +3250,7 @@ void kvm_mmu_free_roots(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu, &invalid_list); if (free_active_root) { - if (mmu->shadow_root_level >= PT64_ROOT_4LEVEL && - (mmu->root_level >= PT64_ROOT_4LEVEL || mmu->direct_map)) { + if (to_shadow_page(mmu->root.hpa)) { mmu_free_root_page(kvm, &mmu->root.hpa, &invalid_list); } else if (mmu->pae_root) { for (i = 0; i < 4; ++i) { |