KVM need to lookup linux pte for getting TLB attributes (WIMGE).
This is similar to how book3s does.
This will be used in follow-up patches.
Signed-off-by: Bharat Bhushan <bharat.bhushan@xxxxxxxxxxxxx>
---
v1->v2
- This is a new change in this version
arch/powerpc/include/asm/kvm_booke.h | 73 ++++++++++++++++++++++++++++++++++
1 files changed, 73 insertions(+), 0 deletions(-)
diff --git a/arch/powerpc/include/asm/kvm_booke.h b/arch/powerpc/include/asm/kvm_booke.h
index d3c1eb3..903624d 100644
--- a/arch/powerpc/include/asm/kvm_booke.h
+++ b/arch/powerpc/include/asm/kvm_booke.h
@@ -102,4 +102,77 @@ static inline ulong kvmppc_get_msr(struct kvm_vcpu *vcpu)
{
return vcpu->arch.shared->msr;
}
+
+/*
+ * Lock and read a linux PTE. If it's present and writable, atomically
+ * set dirty and referenced bits and return the PTE, otherwise return 0.
+ */
+static inline pte_t kvmppc_read_update_linux_pte(pte_t *p, int writing)
+{
+ pte_t pte;
+
+#ifdef PTE_ATOMIC_UPDATES
+ pte_t tmp;
+ /* wait until _PAGE_BUSY is clear then set it atomically */
+#ifdef CONFIG_PPC64
+ __asm__ __volatile__ (
+ "1: ldarx %0,0,%3\n"
+ " andi. %1,%0,%4\n"
+ " bne- 1b\n"
+ " ori %1,%0,%4\n"
+ " stdcx. %1,0,%3\n"
+ " bne- 1b"
+ : "=&r" (pte), "=&r" (tmp), "=m" (*p)
+ : "r" (p), "i" (_PAGE_BUSY)
+ : "cc");
+#else
+ __asm__ __volatile__ (
+ "1: lwarx %0,0,%3\n"
+ " andi. %1,%0,%4\n"
+ " bne- 1b\n"
+ " ori %1,%0,%4\n"
+ " stwcx. %1,0,%3\n"
+ " bne- 1b"
+ : "=&r" (pte), "=&r" (tmp), "=m" (*p)
+ : "r" (p), "i" (_PAGE_BUSY)
+ : "cc");
+#endif
+#else
+ pte = pte_val(*p);
+#endif
+
+ if (pte_present(pte)) {
+ pte = pte_mkyoung(pte);
+ if (writing && pte_write(pte))
+ pte = pte_mkdirty(pte);
+ }
+
+ *p = pte; /* clears _PAGE_BUSY */
+
+ return pte;
+}
+
+static inline pte_t lookup_linux_pte(pgd_t *pgdir, unsigned long hva,
+ int writing, unsigned long *pte_sizep)
+{
+ pte_t *ptep;
+ unsigned long ps = *pte_sizep;
+ unsigned int shift;
+
+ ptep = find_linux_pte_or_hugepte(pgdir, hva, &shift);
+ if (!ptep)
+ return __pte(0);
+ if (shift)
+ *pte_sizep = 1ul << shift;
+ else
+ *pte_sizep = PAGE_SIZE;
+
+ if (ps > *pte_sizep)
+ return __pte(0);
+ if (!pte_present(*ptep))
+ return __pte(0);
+
+ return kvmppc_read_update_linux_pte(ptep, writing);
+}
+
#endif /* __ASM_KVM_BOOKE_H__ */
--
1.7.0.4
--
To unsubscribe from this list: send the line "unsubscribe kvm" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
