[PATCH v4 01/17] KVM: arm64: Add pkvm_private_va_range_pa

[Vincent Donnefort]

Mappings in the pKVM private range are not identity mapped, making the
standard __hyp_pa() unsuitable for translating these addresses.

Introduce pkvm_private_va_range_pa() to resolve physical addresses for
this range by walking the hypervisor page-table. This will be useful for
the upcoming pKVM heap allocator.

Reviewed-by: Fuad Tabba <fuad.tabba at linux.dev>
Tested-by: Fuad Tabba <fuad.tabba at linux.dev>
Signed-off-by: Vincent Donnefort <vdonnefort at google.com>

diff --git a/arch/arm64/kvm/hyp/include/nvhe/mm.h b/arch/arm64/kvm/hyp/include/nvhe/mm.h
index 6e83ce35c2f2..85f1e3c711d9 100644
--- a/arch/arm64/kvm/hyp/include/nvhe/mm.h
+++ b/arch/arm64/kvm/hyp/include/nvhe/mm.h
@@ -30,5 +30,6 @@ int __pkvm_create_private_mapping(phys_addr_t phys, size_t size,
 				  unsigned long *haddr);
 int pkvm_create_stack(phys_addr_t phys, unsigned long *haddr);
 int pkvm_alloc_private_va_range(size_t size, unsigned long *haddr);
+phys_addr_t pkvm_private_va_range_pa(void *va);
 
 #endif /* __KVM_HYP_MM_H */
diff --git a/arch/arm64/kvm/hyp/include/nvhe/spinlock.h b/arch/arm64/kvm/hyp/include/nvhe/spinlock.h
index 7c7ea8c55405..260e14d6d200 100644
--- a/arch/arm64/kvm/hyp/include/nvhe/spinlock.h
+++ b/arch/arm64/kvm/hyp/include/nvhe/spinlock.h
@@ -17,6 +17,8 @@
 #include <asm/lse.h>
 #include <asm/rwonce.h>
 
+#include <linux/cleanup.h>
+
 typedef union hyp_spinlock {
 	u32	__val;
 	struct {
@@ -122,4 +124,6 @@ static inline void hyp_assert_lock_held(hyp_spinlock_t *lock)
 static inline void hyp_assert_lock_held(hyp_spinlock_t *lock) { }
 #endif
 
+DEFINE_LOCK_GUARD_1(hyp_spinlock, hyp_spinlock_t, hyp_spin_lock(_T->lock),
+		    hyp_spin_unlock(_T->lock))
 #endif /* __ARM64_KVM_NVHE_SPINLOCK_H__ */
diff --git a/arch/arm64/kvm/hyp/nvhe/mm.c b/arch/arm64/kvm/hyp/nvhe/mm.c
index 3b0bee496bff..755630c0d15e 100644
--- a/arch/arm64/kvm/hyp/nvhe/mm.c
+++ b/arch/arm64/kvm/hyp/nvhe/mm.c
@@ -90,6 +90,24 @@ int pkvm_alloc_private_va_range(size_t size, unsigned long *haddr)
 	return ret;
 }
 
+/**
+ * pkvm_private_va_range_pa - Translate a private VA to a physical address.
+ * @va:		The private virtual address to translate.
+ *
+ * Return: The physical address corresponding to @va.
+ */
+phys_addr_t pkvm_private_va_range_pa(void *va)
+{
+	kvm_pte_t pte;
+	s8 level;
+
+	guard(hyp_spinlock)(&pkvm_pgd_lock);
+	WARN_ON(kvm_pgtable_get_leaf(&pkvm_pgtable, (u64)va, &pte, &level));
+	WARN_ON(!kvm_pte_valid(pte));
+
+	return kvm_pte_to_phys(pte) + ((u64)va & (kvm_granule_size(level) - 1));
+}
+
 int __pkvm_create_private_mapping(phys_addr_t phys, size_t size,
 				  enum kvm_pgtable_prot prot,
 				  unsigned long *haddr)
-- 
2.55.0.508.g3f0d502094-goog