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[16/20] KVM: PPC: Book3S HV: radix: Refine IO region partition scope attributes

Message ID 20190311165051.1149-17-leonardo@linux.ibm.com
State New
Headers show
Series Avoid migration issues with aligned 2MB THB | expand

Commit Message

Leonardo Bras March 11, 2019, 4:50 p.m. UTC 
From: Nicholas Piggin <npiggin@gmail.com>

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 <npiggin@gmail.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Leonardo Bras <leonardo@linux.ibm.com>
---
 arch/powerpc/kvm/book3s_64_mmu_radix.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)
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Patch

diff --git a/arch/powerpc/kvm/book3s_64_mmu_radix.c b/arch/powerpc/kvm/book3s_64_mmu_radix.c
index e55db915af49..b0ba3628adc2 100644
--- a/arch/powerpc/kvm/book3s_64_mmu_radix.c
+++ b/arch/powerpc/kvm/book3s_64_mmu_radix.c
@@ -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 */