diff options
author | Michael Ellerman <mpe@ellerman.id.au> | 2020-06-03 06:44:51 +0300 |
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committer | Michael Ellerman <mpe@ellerman.id.au> | 2020-06-03 06:44:51 +0300 |
commit | 1395375c592770fe5158a592944aaeed67fa94ff (patch) | |
tree | 82cd6ab7956f36733269a6f2a3041683b2db04f4 /arch/powerpc/kvm/book3s_64_mmu_radix.c | |
parent | 4336b9337824a60a0b10013c622caeee99460db5 (diff) | |
parent | bf8036a4098d1548cdccf9ed5c523ef4e83e3c68 (diff) | |
download | linux-1395375c592770fe5158a592944aaeed67fa94ff.tar.xz |
Merge branch 'topic/ppc-kvm' into next
Merge one more commit from the topic branch we shared with the kvm-ppc
tree.
This brings in a fix to the code that scans for dirty pages during
migration of a VM, which was incorrectly triggering a warning.
Diffstat (limited to 'arch/powerpc/kvm/book3s_64_mmu_radix.c')
-rw-r--r-- | arch/powerpc/kvm/book3s_64_mmu_radix.c | 35 |
1 files changed, 29 insertions, 6 deletions
diff --git a/arch/powerpc/kvm/book3s_64_mmu_radix.c b/arch/powerpc/kvm/book3s_64_mmu_radix.c index 271f1c3d8443..954fd7a12149 100644 --- a/arch/powerpc/kvm/book3s_64_mmu_radix.c +++ b/arch/powerpc/kvm/book3s_64_mmu_radix.c @@ -1040,7 +1040,7 @@ static int kvm_radix_test_clear_dirty(struct kvm *kvm, { unsigned long gfn = memslot->base_gfn + pagenum; unsigned long gpa = gfn << PAGE_SHIFT; - pte_t *ptep; + pte_t *ptep, pte; unsigned int shift; int ret = 0; unsigned long old, *rmapp; @@ -1048,12 +1048,35 @@ static int kvm_radix_test_clear_dirty(struct kvm *kvm, if (kvm->arch.secure_guest & KVMPPC_SECURE_INIT_DONE) return ret; - ptep = find_kvm_secondary_pte(kvm, gpa, &shift); - if (ptep && pte_present(*ptep) && pte_dirty(*ptep)) { - ret = 1; - if (shift) - ret = 1 << (shift - PAGE_SHIFT); + /* + * For performance reasons we don't hold kvm->mmu_lock while walking the + * partition scoped table. + */ + ptep = find_kvm_secondary_pte_unlocked(kvm, gpa, &shift); + if (!ptep) + return 0; + + pte = READ_ONCE(*ptep); + if (pte_present(pte) && pte_dirty(pte)) { spin_lock(&kvm->mmu_lock); + /* + * Recheck the pte again + */ + if (pte_val(pte) != pte_val(*ptep)) { + /* + * We have KVM_MEM_LOG_DIRTY_PAGES enabled. Hence we can + * only find PAGE_SIZE pte entries here. We can continue + * to use the pte addr returned by above page table + * walk. + */ + if (!pte_present(*ptep) || !pte_dirty(*ptep)) { + spin_unlock(&kvm->mmu_lock); + return 0; + } + } + + ret = 1; + VM_BUG_ON(shift); old = kvmppc_radix_update_pte(kvm, ptep, _PAGE_DIRTY, 0, gpa, shift); kvmppc_radix_tlbie_page(kvm, gpa, shift, kvm->arch.lpid); |