KVM: arm64: Support PUD hugepage in stage2_is_exec()

In preparation for creating PUD hugepages at stage 2, add support for
detecting execute permissions on PUD page table entries. Faults due to
lack of execute permissions on page table entries is used to perform
i-cache invalidation on first execute.

Provide trivial implementations of arm32 helpers to allow sharing of
code.

Signed-off-by: Punit Agrawal <punit.agrawal@arm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@arm.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
[ Replaced BUG() => WARN_ON(1) in arm32 PUD helpers ]
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

diff --git a/arch/arm/include/asm/kvm_mmu.h b/arch/arm/include/asm/kvm_mmu.h
index 9fe6c30eb2fccd255e1ceddf3a1d432bb011421e..a49655fe7cd90f46a85d7599f75e36bd3a1c40b6 100644 (file)
--- a/arch/arm/include/asm/kvm_mmu.h
+++ b/arch/arm/include/asm/kvm_mmu.h
@@ -102,6 +102,12 @@ static inline bool kvm_s2pud_readonly(pud_t *pud)
        return false;
 }
 
+static inline bool kvm_s2pud_exec(pud_t *pud)
+{
+       WARN_ON(1);
+       return false;
+}
+
 static inline pte_t kvm_s2pte_mkwrite(pte_t pte)
 {
        pte_val(pte) |= L_PTE_S2_RDWR;

diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h
index 8da6d1b2a196bd02229a6921f56c63b6239700e3..c755b37b3f927e6727d900bb869da477240fffeb 100644 (file)
--- a/arch/arm64/include/asm/kvm_mmu.h
+++ b/arch/arm64/include/asm/kvm_mmu.h
@@ -261,6 +261,11 @@ static inline bool kvm_s2pud_readonly(pud_t *pudp)
        return kvm_s2pte_readonly((pte_t *)pudp);
 }
 
+static inline bool kvm_s2pud_exec(pud_t *pudp)
+{
+       return !(READ_ONCE(pud_val(*pudp)) & PUD_S2_XN);
+}
+
 #define hyp_pte_table_empty(ptep) kvm_page_empty(ptep)
 
 #ifdef __PAGETABLE_PMD_FOLDED

diff --git a/arch/arm64/include/asm/pgtable-hwdef.h b/arch/arm64/include/asm/pgtable-hwdef.h
index 1d7d8da2ef9b301dec85e80fe1825b95f71aa54b..336e24cddc87df1bc64aa476a5d38b4544e7b7be 100644 (file)
--- a/arch/arm64/include/asm/pgtable-hwdef.h
+++ b/arch/arm64/include/asm/pgtable-hwdef.h
@@ -193,6 +193,8 @@
 #define PMD_S2_RDWR            (_AT(pmdval_t, 3) << 6)   /* HAP[2:1] */
 #define PMD_S2_XN              (_AT(pmdval_t, 2) << 53)  /* XN[1:0] */
 
+#define PUD_S2_XN              (_AT(pudval_t, 2) << 53)  /* XN[1:0] */
+
 /*
  * Memory Attribute override for Stage-2 (MemAttr[3:0])
  */

diff --git a/virt/kvm/arm/mmu.c b/virt/kvm/arm/mmu.c
index 1c669c3c12081f74c35b0cd6c59bd61a4bd12293..8e44dccd1b476ddeb50adbe89577d48ab498870c 100644 (file)
--- a/virt/kvm/arm/mmu.c
+++ b/virt/kvm/arm/mmu.c
@@ -1083,23 +1083,66 @@ static int stage2_set_pmd_huge(struct kvm *kvm, struct kvm_mmu_memory_cache
        return 0;
 }
 
-static bool stage2_is_exec(struct kvm *kvm, phys_addr_t addr)
+/*
+ * stage2_get_leaf_entry - walk the stage2 VM page tables and return
+ * true if a valid and present leaf-entry is found. A pointer to the
+ * leaf-entry is returned in the appropriate level variable - pudpp,
+ * pmdpp, ptepp.
+ */
+static bool stage2_get_leaf_entry(struct kvm *kvm, phys_addr_t addr,
+                                 pud_t **pudpp, pmd_t **pmdpp, pte_t **ptepp)
 {
+       pud_t *pudp;
        pmd_t *pmdp;
        pte_t *ptep;
 
-       pmdp = stage2_get_pmd(kvm, NULL, addr);
+       *pudpp = NULL;
+       *pmdpp = NULL;
+       *ptepp = NULL;
+
+       pudp = stage2_get_pud(kvm, NULL, addr);
+       if (!pudp || stage2_pud_none(kvm, *pudp) || !stage2_pud_present(kvm, *pudp))
+               return false;
+
+       if (stage2_pud_huge(kvm, *pudp)) {
+               *pudpp = pudp;
+               return true;
+       }
+
+       pmdp = stage2_pmd_offset(kvm, pudp, addr);
        if (!pmdp || pmd_none(*pmdp) || !pmd_present(*pmdp))
                return false;
 
-       if (pmd_thp_or_huge(*pmdp))
-               return kvm_s2pmd_exec(pmdp);
+       if (pmd_thp_or_huge(*pmdp)) {
+               *pmdpp = pmdp;
+               return true;
+       }
 
        ptep = pte_offset_kernel(pmdp, addr);
        if (!ptep || pte_none(*ptep) || !pte_present(*ptep))
                return false;
 
-       return kvm_s2pte_exec(ptep);
+       *ptepp = ptep;
+       return true;
+}
+
+static bool stage2_is_exec(struct kvm *kvm, phys_addr_t addr)
+{
+       pud_t *pudp;
+       pmd_t *pmdp;
+       pte_t *ptep;
+       bool found;
+
+       found = stage2_get_leaf_entry(kvm, addr, &pudp, &pmdp, &ptep);
+       if (!found)
+               return false;
+
+       if (pudp)
+               return kvm_s2pud_exec(pudp);
+       else if (pmdp)
+               return kvm_s2pmd_exec(pmdp);
+       else
+               return kvm_s2pte_exec(ptep);
 }
 
 static int stage2_set_pte(struct kvm *kvm, struct kvm_mmu_memory_cache *cache,