Add pkvm_pgtable_lookup API for pgtable. It can be used to walk page
table for a translation lookup, such as looking up if a page mapping is
present in a specific page table.
Signed-off-by: Jason Chen CJ <jason.cj.chen@xxxxxxxxx>
---
arch/x86/kvm/vmx/pkvm/hyp/ept.c | 6 +++
arch/x86/kvm/vmx/pkvm/hyp/memory.h | 2 +
arch/x86/kvm/vmx/pkvm/hyp/mmu.c | 6 +++
arch/x86/kvm/vmx/pkvm/hyp/pgtable.c | 74 ++++++++++++++++++++++++++++-
arch/x86/kvm/vmx/pkvm/hyp/pgtable.h | 5 ++
5 files changed, 92 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kvm/vmx/pkvm/hyp/ept.c b/arch/x86/kvm/vmx/pkvm/hyp/ept.c
index 5b7b0d84b457..10d226d3ec59 100644
--- a/arch/x86/kvm/vmx/pkvm/hyp/ept.c
+++ b/arch/x86/kvm/vmx/pkvm/hyp/ept.c
@@ -102,6 +102,11 @@ static int ept_level_to_entries(int level)
return SPTE_ENT_PER_PAGE;
}
+static u64 ept_level_page_mask(int level)
+{
+ return (~((1UL << SPTE_LEVEL_SHIFT(level)) - 1));
+}
+
static unsigned long ept_level_to_size(int level)
{
return KVM_HPAGE_SIZE(level);
@@ -119,6 +124,7 @@ struct pkvm_pgtable_ops ept_ops = {
.pgt_entry_to_phys = ept_entry_to_phys,
.pgt_entry_to_prot = ept_entry_to_prot,
.pgt_entry_to_index = ept_entry_to_index,
+ .pgt_level_page_mask = ept_level_page_mask,
.pgt_entry_is_leaf = ept_entry_is_leaf,
.pgt_level_entry_size = ept_level_entry_size,
.pgt_level_to_entries = ept_level_to_entries,
diff --git a/arch/x86/kvm/vmx/pkvm/hyp/memory.h b/arch/x86/kvm/vmx/pkvm/hyp/memory.h
index c2eee487687a..87b53275bc74 100644
--- a/arch/x86/kvm/vmx/pkvm/hyp/memory.h
+++ b/arch/x86/kvm/vmx/pkvm/hyp/memory.h
@@ -7,6 +7,8 @@
#include <asm/kvm_pkvm.h>
+#define INVALID_ADDR (~0UL)
+
unsigned long pkvm_virt_to_symbol_phys(void *virt);
#define __pkvm_pa_symbol(x) pkvm_virt_to_symbol_phys((void *)x)
diff --git a/arch/x86/kvm/vmx/pkvm/hyp/mmu.c b/arch/x86/kvm/vmx/pkvm/hyp/mmu.c
index 0902f457d682..7684d16dd2c9 100644
--- a/arch/x86/kvm/vmx/pkvm/hyp/mmu.c
+++ b/arch/x86/kvm/vmx/pkvm/hyp/mmu.c
@@ -109,6 +109,11 @@ static void mmu_set_entry(void *ptep, u64 pte)
native_set_pte((pte_t *)ptep, native_make_pte(pte));
}
+static u64 mmu_level_page_mask(int level)
+{
+ return (~((1UL << SPTE_LEVEL_SHIFT(level)) - 1));
+}
+
struct pkvm_pgtable_ops mmu_ops = {
.pgt_entry_present = mmu_entry_present,
.pgt_entry_huge = mmu_entry_huge,
@@ -116,6 +121,7 @@ struct pkvm_pgtable_ops mmu_ops = {
.pgt_entry_to_phys = mmu_entry_to_phys,
.pgt_entry_to_prot = mmu_entry_to_prot,
.pgt_entry_to_index = mmu_entry_to_index,
+ .pgt_level_page_mask = mmu_level_page_mask,
.pgt_entry_is_leaf = mmu_entry_is_leaf,
.pgt_level_entry_size = mmu_level_entry_size,
.pgt_level_to_entries = mmu_level_to_entries,
diff --git a/arch/x86/kvm/vmx/pkvm/hyp/pgtable.c b/arch/x86/kvm/vmx/pkvm/hyp/pgtable.c
index 29af06547ad1..d55acc84f4e1 100644
--- a/arch/x86/kvm/vmx/pkvm/hyp/pgtable.c
+++ b/arch/x86/kvm/vmx/pkvm/hyp/pgtable.c
@@ -27,6 +27,13 @@ struct pkvm_pgtable_unmap_data {
unsigned long phys;
};
+struct pkvm_pgtable_lookup_data {
+ unsigned long vaddr;
+ unsigned long phys;
+ u64 prot;
+ int level;
+};
+
static bool leaf_mapping_allowed(struct pkvm_pgtable_ops *pgt_ops,
unsigned long vaddr,
unsigned long vaddr_end,
@@ -273,6 +280,41 @@ static int pgtable_unmap_cb(struct pkvm_pgtable *pgt, unsigned long vaddr,
return 0;
}
+static int pgtable_lookup_cb(struct pkvm_pgtable *pgt,
+ unsigned long aligned_vaddr,
+ unsigned long aligned_vaddr_end,
+ int level,
+ void *ptep,
+ unsigned long flags,
+ struct pgt_flush_data *flush_data,
+ void *const arg)
+{
+ struct pkvm_pgtable_lookup_data *data = arg;
+ struct pkvm_pgtable_ops *pgt_ops = pgt->pgt_ops;
+ u64 pte = atomic64_read((atomic64_t *)ptep);
+
+ data->phys = INVALID_ADDR;
+ data->prot = 0;
+ data->level = level;
+
+ /*
+ * This cb shall only be called for leaf, if now it is not a leaf
+ * that means the pte is changed by others, we shall re-walk the pgtable
+ */
+ if (unlikely(!pgt_ops->pgt_entry_is_leaf(&pte, level)))
+ return -EAGAIN;
+
+ if (pgt_ops->pgt_entry_present(&pte)) {
+ unsigned long offset =
+ data->vaddr & ~pgt_ops->pgt_level_page_mask(level);
+
+ data->phys = pgt_ops->pgt_entry_to_phys(&pte) + offset;
+ data->prot = pgt_ops->pgt_entry_to_prot(&pte);
+ }
+
+ return PGTABLE_WALK_DONE;
+}
+
static int pgtable_free_cb(struct pkvm_pgtable *pgt,
unsigned long vaddr,
unsigned long vaddr_end,
@@ -367,7 +409,7 @@ static int _pgtable_walk(struct pgt_walk_data *data, void *ptep, int level)
break;
ret = pgtable_visit(data, (ptep + idx * entry_size), level);
- if (ret < 0)
+ if (ret)
return ret;
}
@@ -469,6 +511,36 @@ int pkvm_pgtable_unmap(struct pkvm_pgtable *pgt, unsigned long vaddr_start,
return pgtable_walk(pgt, vaddr_start, size, &walker);
}
+void pkvm_pgtable_lookup(struct pkvm_pgtable *pgt, unsigned long vaddr,
+ unsigned long *pphys, u64 *pprot, int *plevel)
+{
+ struct pkvm_pgtable_lookup_data data = {
+ .vaddr = vaddr,
+ };
+ struct pkvm_pgtable_walker walker = {
+ .cb = pgtable_lookup_cb,
+ .arg = &data,
+ .flags = PKVM_PGTABLE_WALK_LEAF,
+ };
+ int ret, retry_cnt = 0;
+
+retry:
+ ret = pgtable_walk(pgt, vaddr, PAGE_SIZE, &walker);
+ /*
+ * we give 5 times chance to re-walk pgtable if others change the
+ * PTE during above pgtable walk.
+ */
+ if ((ret == -EAGAIN) && (retry_cnt++ < 5))
+ goto retry;
+
+ if (pphys)
+ *pphys = data.phys;
+ if (pprot)
+ *pprot = data.prot;
+ if (plevel)
+ *plevel = data.level;
+}
+
void pkvm_pgtable_destroy(struct pkvm_pgtable *pgt)
{
unsigned long size;
diff --git a/arch/x86/kvm/vmx/pkvm/hyp/pgtable.h b/arch/x86/kvm/vmx/pkvm/hyp/pgtable.h
index 5035b21e6aa0..00d3742b7f48 100644
--- a/arch/x86/kvm/vmx/pkvm/hyp/pgtable.h
+++ b/arch/x86/kvm/vmx/pkvm/hyp/pgtable.h
@@ -25,6 +25,7 @@ struct pkvm_pgtable_ops {
unsigned long (*pgt_entry_to_phys)(void *pte);
u64 (*pgt_entry_to_prot)(void *pte);
int (*pgt_entry_to_index)(unsigned long vaddr, int level);
+ u64 (*pgt_level_page_mask)(int level);
bool (*pgt_entry_is_leaf)(void *ptep, int level);
int (*pgt_level_entry_size)(int level);
int (*pgt_level_to_entries)(int level);
@@ -51,6 +52,8 @@ typedef int (*pgtable_visit_fn_t)(struct pkvm_pgtable *pgt, unsigned long vaddr,
unsigned long flags, struct pgt_flush_data *flush_data,
void *const arg);
+#define PGTABLE_WALK_DONE 1
+
struct pkvm_pgtable_walker {
const pgtable_visit_fn_t cb;
void *const arg;
@@ -72,5 +75,7 @@ int pkvm_pgtable_map(struct pkvm_pgtable *pgt, unsigned long vaddr_start,
int pgsz_mask, u64 entry_prot);
int pkvm_pgtable_unmap(struct pkvm_pgtable *pgt, unsigned long vaddr_start,
unsigned long phys_start, unsigned long size);
+void pkvm_pgtable_lookup(struct pkvm_pgtable *pgt, unsigned long vaddr,
+ unsigned long *pphys, u64 *pprot, int *plevel);
void pkvm_pgtable_destroy(struct pkvm_pgtable *pgt);
#endif
--
2.25.1
