On Thu, Nov 22, 2012 at 7:59 PM, Christoffer Dall <c.dall@xxxxxxxxxxxxxxxxxxxxxx> wrote:
From: Christoffer Dall <cdall@xxxxxxxxxxxxxxx>
The set_pte_ext function orr'ed the RDONLY bit onto the PTEs, which is
bit[7], which is HAP[1] and causes writable access to the pages.
This was unfortunate.
Cc: Nicolas Viennot <nviennot@xxxxxxxxxxxxxxx>
Cc: Jeremy C. Andrus <jeremya@xxxxxxxxxxxxxxx>
Signed-off-by: Christoffer Dall <c.dall@xxxxxxxxxxxxxxxxxxxxxx>
---
arch/arm/kvm/mmu.c | 27 +++++++++++++++------------
1 file changed, 15 insertions(+), 12 deletions(-)
diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c
index 7b0e6e5..720bbd5 100644
--- a/arch/arm/kvm/mmu.c
+++ b/arch/arm/kvm/mmu.c
@@ -41,6 +41,16 @@ static void kvm_tlb_flush_vmid(struct kvm *kvm)
kvm_call_hyp(__kvm_tlb_flush_vmid, kvm);
}
+static void set_pte(pte_t *pte, pte_t new_pte)
+{
+ *pte = new_pte;
+ /*
+ * flush_pmd_entry just takes a void pointer and cleans the necessary
+ * cache entries, so we can reuse the function for ptes.
+ */
+ flush_pmd_entry(pte);
+}
+
static int mmu_topup_memory_cache(struct kvm_mmu_memory_cache *cache,
int min, int max)
{
@@ -140,13 +150,13 @@ static void create_hyp_pte_mappings(pmd_t *pmd, unsigned long start,
pte = pte_offset_kernel(pmd, addr);
if (pfn_base) {
BUG_ON(pfn_valid(*pfn_base));
- set_pte_ext(pte, pfn_pte(*pfn_base, prot), 0);
+ set_pte(pte, pfn_pte(*pfn_base, prot));
(*pfn_base)++;
} else {
struct page *page;
BUG_ON(!virt_addr_valid(addr));
page = virt_to_page(addr);
- set_pte_ext(pte, mk_pte(page, prot), 0);
+ set_pte(pte, mk_pte(page, prot));
}
}
@@ -393,7 +403,7 @@ static void stage2_clear_pte(struct kvm *kvm, phys_addr_t addr)
return;
pte = pte_offset_kernel(pmd, addr);
- set_pte_ext(pte, __pte(0), 0);
+ set_pte(pte, __pte(0));
page = virt_to_page(pte);
put_page(page);
@@ -459,7 +469,7 @@ static int stage2_set_pte(struct kvm *kvm, struct kvm_mmu_memory_cache *cache,
/* Create 2nd stage page table mapping - Level 3 */
old_pte = *pte;
- set_pte_ext(pte, *new_pte, 0);
+ set_pte(pte, *new_pte);
if (pte_present(old_pte))
kvm_tlb_flush_vmid(kvm);
else
@@ -576,14 +586,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
out_unlock:
spin_unlock(&vcpu->kvm->mmu_lock);
- /*
- * XXX TODO FIXME:
-- * This is _really_ *weird* !!!
-- * We should be calling the _clean version, because we set the pfn dirty
- * if we map the page writable, but this causes memory failures in
- * guests under heavy memory pressure on the host and heavy swapping.
- */
- kvm_release_pfn_dirty(pfn);
+ kvm_release_pfn_clean(pfn);
return 0;
}
--
1.7.9.5
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