[RFC PATCH 3/7] kvm: arm64: Add level_apply parameter for stage2_attr_walker

Keqian Zhu
2021-01-26T12:47:47Z

In order to change PTEs of some specific levels, the level_apply
parameter can be used as a level mask.

This has no fuctional change for current code.

Signed-off-by: Keqian Zhu <zhukeqian1@huawei.com>
---
arch/arm64/kvm/hyp/pgtable.c | 19 ++++++++++++-------
1 file changed, 12 insertions(+), 7 deletions(-)

diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c
index 4915ba35f93b..0f8a319f16fe 100644
--- a/arch/arm64/kvm/hyp/pgtable.c
+++ b/arch/arm64/kvm/hyp/pgtable.c
@@ -734,6 +734,7 @@ struct stage2_attr_data {
kvm_pte_t attr_clr;
kvm_pte_t pte;
u32 level;
+ u32 level_apply;
};

static int stage2_attr_walker(u64 addr, u64 end, u32 level, kvm_pte_t *ptep,
@@ -743,6 +744,9 @@ static int stage2_attr_walker(u64 addr, u64 end, u32 level, kvm_pte_t *ptep,
kvm_pte_t pte = *ptep;
struct stage2_attr_data *data = arg;

+ if (!(data->level_apply & BIT(level)))
+ return 0;
+
if (!kvm_pte_valid(pte))
return 0;

@@ -753,14 +757,15 @@ static int stage2_attr_walker(u64 addr, u64 end, u32 level, kvm_pte_t *ptep,

static int stage2_update_leaf_attrs(struct kvm_pgtable *pgt, u64 addr,
u64 size, kvm_pte_t attr_set,
- kvm_pte_t attr_clr, kvm_pte_t *orig_pte,
- u32 *level)
+ kvm_pte_t attr_clr, u32 level_apply,
+ kvm_pte_t *orig_pte, u32 *level)
{
int ret;
kvm_pte_t attr_mask = KVM_PTE_LEAF_ATTR_LO | KVM_PTE_LEAF_ATTR_HI;
struct stage2_attr_data data = {
.attr_set = attr_set & attr_mask,
.attr_clr = attr_clr & attr_mask,
+ .level_apply = level_apply,
};
struct kvm_pgtable_walker walker = {
.cb = stage2_attr_walker,
@@ -783,7 +788,7 @@ static int stage2_update_leaf_attrs(struct kvm_pgtable *pgt, u64 addr,
int kvm_pgtable_stage2_wrprotect(struct kvm_pgtable *pgt, u64 addr, u64 size)
{
return stage2_update_leaf_attrs(pgt, addr, size, 0,
- KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W,
+ KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W, -1,
NULL, NULL);
}

@@ -791,7 +796,7 @@ kvm_pte_t kvm_pgtable_stage2_mkyoung(struct kvm_pgtable *pgt, u64 addr)
{
kvm_pte_t pte = 0;
stage2_update_leaf_attrs(pgt, addr, 1, KVM_PTE_LEAF_ATTR_LO_S2_AF, 0,
- &pte, NULL);
+ -1, &pte, NULL);
dsb(ishst);
return pte;
}
@@ -800,7 +805,7 @@ kvm_pte_t kvm_pgtable_stage2_mkold(struct kvm_pgtable *pgt, u64 addr)
{
kvm_pte_t pte = 0;
stage2_update_leaf_attrs(pgt, addr, 1, 0, KVM_PTE_LEAF_ATTR_LO_S2_AF,
- &pte, NULL);
+ -1, &pte, NULL);
/*
* "But where's the TLBI?!", you scream.
* "Over in the core code", I sigh.
@@ -813,7 +818,7 @@ kvm_pte_t kvm_pgtable_stage2_mkold(struct kvm_pgtable *pgt, u64 addr)
bool kvm_pgtable_stage2_is_young(struct kvm_pgtable *pgt, u64 addr)
{
kvm_pte_t pte = 0;
- stage2_update_leaf_attrs(pgt, addr, 1, 0, 0, &pte, NULL);
+ stage2_update_leaf_attrs(pgt, addr, 1, 0, 0, -1, &pte, NULL);
return pte & KVM_PTE_LEAF_ATTR_LO_S2_AF;
}

@@ -833,7 +838,7 @@ int kvm_pgtable_stage2_relax_perms(struct kvm_pgtable *pgt, u64 addr,
if (prot & KVM_PGTABLE_PROT_X)
clr |= KVM_PTE_LEAF_ATTR_HI_S2_XN;

- ret = stage2_update_leaf_attrs(pgt, addr, 1, set, clr, NULL, &level);
+ ret = stage2_update_leaf_attrs(pgt, addr, 1, set, clr, -1, NULL, &level);
if (!ret)
kvm_call_hyp(__kvm_tlb_flush_vmid_ipa, pgt->mmu, addr, level);
return ret;