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kvm: x86/mmu: Support changed pte notifier in tdp MMU

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In order to interoperate correctly with the rest of KVM and other Linux
subsystems, the TDP MMU must correctly handle various MMU notifiers. Add
a hook and handle the change_pte MMU notifier.

Tested by running kvm-unit-tests and KVM selftests on an Intel Haswell
machine. This series introduced no new failures.

This series can be viewed in Gerrit at:
	https://linux-review.googlesource.com/c/virt/kvm/kvm/+/2538

Signed-off-by: Ben Gardon <bgardon@google.com>
Message-Id: <20201014182700.2888246-15-bgardon@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Ben Gardon 2020-10-14 11:26:54 -07:00 committed by Paolo Bonzini
parent f8e144971c
commit 1d8dd6b3f1
3 changed files with 67 additions and 1 deletions
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9
arch/x86/kvm/mmu/mmu.c
View File

@ -1509,7 +1509,14 @@ int kvm_unmap_hva_range(struct kvm *kvm, unsigned long start, unsigned long end,
int kvm_set_spte_hva(struct kvm *kvm, unsigned long hva, pte_t pte)
{
return kvm_handle_hva(kvm, hva, (unsigned long)&pte, kvm_set_pte_rmapp);
int r;
r = kvm_handle_hva(kvm, hva, (unsigned long)&pte, kvm_set_pte_rmapp);
if (kvm->arch.tdp_mmu_enabled)
r |= kvm_tdp_mmu_set_spte_hva(kvm, hva, &pte);
return r;
}
static int kvm_age_rmapp(struct kvm *kvm, struct kvm_rmap_head *rmap_head,

56
arch/x86/kvm/mmu/tdp_mmu.c
View File

@ -671,3 +671,59 @@ int kvm_tdp_mmu_test_age_hva(struct kvm *kvm, unsigned long hva)
return kvm_tdp_mmu_handle_hva_range(kvm, hva, hva + 1, 0,
test_age_gfn);
}
/*
* Handle the changed_pte MMU notifier for the TDP MMU.
* data is a pointer to the new pte_t mapping the HVA specified by the MMU
* notifier.
* Returns non-zero if a flush is needed before releasing the MMU lock.
*/
static int set_tdp_spte(struct kvm *kvm, struct kvm_memory_slot *slot,
struct kvm_mmu_page *root, gfn_t gfn, gfn_t unused,
unsigned long data)
{
struct tdp_iter iter;
pte_t *ptep = (pte_t *)data;
kvm_pfn_t new_pfn;
u64 new_spte;
int need_flush = 0;
WARN_ON(pte_huge(*ptep));
new_pfn = pte_pfn(*ptep);
tdp_root_for_each_pte(iter, root, gfn, gfn + 1) {
if (iter.level != PG_LEVEL_4K)
continue;
if (!is_shadow_present_pte(iter.old_spte))
break;
tdp_mmu_set_spte(kvm, &iter, 0);
kvm_flush_remote_tlbs_with_address(kvm, iter.gfn, 1);
if (!pte_write(*ptep)) {
new_spte = kvm_mmu_changed_pte_notifier_make_spte(
iter.old_spte, new_pfn);
tdp_mmu_set_spte(kvm, &iter, new_spte);
}
need_flush = 1;
}
if (need_flush)
kvm_flush_remote_tlbs_with_address(kvm, gfn, 1);
return 0;
}
int kvm_tdp_mmu_set_spte_hva(struct kvm *kvm, unsigned long address,
pte_t *host_ptep)
{
return kvm_tdp_mmu_handle_hva_range(kvm, address, address + 1,
(unsigned long)host_ptep,
set_tdp_spte);
}

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

@ -25,4 +25,7 @@ int kvm_tdp_mmu_zap_hva_range(struct kvm *kvm, unsigned long start,
int kvm_tdp_mmu_age_hva_range(struct kvm *kvm, unsigned long start,
unsigned long end);
int kvm_tdp_mmu_test_age_hva(struct kvm *kvm, unsigned long hva);
int kvm_tdp_mmu_set_spte_hva(struct kvm *kvm, unsigned long address,
pte_t *host_ptep);
#endif /* __KVM_X86_MMU_TDP_MMU_H */