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KVM: PPC: Book3S HV: radix refine IO region partition scope attributes

PATCH New Nicholas Piggin 1 participant 1 message May 17, 2018

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Nicholas Piggin

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PATCH v3 7/8 KVM: PPC: Book3S HV: radix refine IO region partition scope attributes

When the radix fault handler has no page from the process address space (e.g., for IO memory), it looks up the process pte and sets partition table pte using that to get attributes like CI and guarded. If the process table entry is to be writable, set _PAGE_DIRTY as well to avoid an RC update. If not, then ensure _PAGE_DIRTY does not come across. Set _PAGE_ACCESSED as well to avoid RC update.

Signed-off-by Nicholas Piggin <[email protected]>
---
 arch/powerpc/kvm/book3s_64_mmu_radix.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)
arch/powerpc/kvm/book3s_64_mmu_radix.c +7 -3
index e55db915af49..b0ba3628adc2 100644
@@ -674,9 +674,13 @@ int kvmppc_book3s_radix_page_fault(struct kvm_run *run, struct kvm_vcpu *vcpu,
 			unsigned long mask = (1ul << shift) - PAGE_SIZE;
 			pte = __pte(pte_val(pte) | (hva & mask));
 		}
-		if (!(writing || upgrade_write))
-			pte = __pte(pte_val(pte) & ~ _PAGE_WRITE);
-		pte = __pte(pte_val(pte) | _PAGE_EXEC);
+		pte = __pte(pte_val(pte) | _PAGE_EXEC | _PAGE_ACCESSED);
+		if (writing || upgrade_write) {
+			if (pte_val(pte) & _PAGE_WRITE)
+				pte = __pte(pte_val(pte) | _PAGE_DIRTY);
+		} else {
+			pte = __pte(pte_val(pte) & ~(_PAGE_WRITE | _PAGE_DIRTY));
+		}
 	}
 
 	/* Allocate space in the tree and write the PTE */
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