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| author | Sean Christopherson <sean.j.christopherson@intel.com> | 2021-07-02 15:04:51 -0700 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2021-08-02 09:36:37 -0400 |
| commit | 7fa2a347512ab06ea1558302564879c060d52b0c (patch) | |
| tree | 73fef19a673dc8c5b2e80f11f084163eca998f4a /arch/x86/kvm/mmu/mmu.c | |
| parent | 03fffc5493c8c8d850586df5740c985026c313bf (diff) | |
| download | lwn-7fa2a347512ab06ea1558302564879c060d52b0c.tar.gz lwn-7fa2a347512ab06ea1558302564879c060d52b0c.zip | |
KVM: x86/mmu: Return old SPTE from mmu_spte_clear_track_bits()
Return the old SPTE when clearing a SPTE and push the "old SPTE present"
check to the caller. Private shadow page support will use the old SPTE
in rmap_remove() to determine whether or not there is a linked private
shadow page.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <b16bac1fd1357aaf39e425aab2177d3f89ee8318.1625186503.git.isaku.yamahata@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/mmu/mmu.c')
| -rw-r--r-- | arch/x86/kvm/mmu/mmu.c | 12 |
1 files changed, 7 insertions, 5 deletions
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 85c70492f863..d9e3ac6dda05 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -592,9 +592,9 @@ static bool mmu_spte_update(u64 *sptep, u64 new_spte) * Rules for using mmu_spte_clear_track_bits: * It sets the sptep from present to nonpresent, and track the * state bits, it is used to clear the last level sptep. - * Returns non-zero if the PTE was previously valid. + * Returns the old PTE. */ -static int mmu_spte_clear_track_bits(u64 *sptep) +static u64 mmu_spte_clear_track_bits(u64 *sptep) { kvm_pfn_t pfn; u64 old_spte = *sptep; @@ -605,7 +605,7 @@ static int mmu_spte_clear_track_bits(u64 *sptep) old_spte = __update_clear_spte_slow(sptep, 0ull); if (!is_shadow_present_pte(old_spte)) - return 0; + return old_spte; pfn = spte_to_pfn(old_spte); @@ -622,7 +622,7 @@ static int mmu_spte_clear_track_bits(u64 *sptep) if (is_dirty_spte(old_spte)) kvm_set_pfn_dirty(pfn); - return 1; + return old_spte; } /* @@ -1119,7 +1119,9 @@ out: static void drop_spte(struct kvm *kvm, u64 *sptep) { - if (mmu_spte_clear_track_bits(sptep)) + u64 old_spte = mmu_spte_clear_track_bits(sptep); + + if (is_shadow_present_pte(old_spte)) rmap_remove(kvm, sptep); } |