[PATCH v2 14/16] KVM: arm64: Refactor protected nVHE stage-1 locking

Quentin Perret
2021-07-26T09:30:08Z

Refactor the hypervisor stage-1 locking in nVHE protected mode to expose
a new pkvm_create_mappings_locked() function. This will be used in later
patches to allow walking and changing the hypervisor stage-1 without
releasing the lock.

Signed-off-by: Quentin Perret <qperret@google.com>
---
arch/arm64/kvm/hyp/include/nvhe/mm.h | 1 +
arch/arm64/kvm/hyp/nvhe/mm.c | 17 +++++++++++++++--
2 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/kvm/hyp/include/nvhe/mm.h b/arch/arm64/kvm/hyp/include/nvhe/mm.h
index 8ec3a5a7744b..c76d7136ed9b 100644
--- a/arch/arm64/kvm/hyp/include/nvhe/mm.h
+++ b/arch/arm64/kvm/hyp/include/nvhe/mm.h
@@ -23,6 +23,7 @@ int hyp_map_vectors(void);
int hyp_back_vmemmap(phys_addr_t phys, unsigned long size, phys_addr_t back);
int pkvm_cpu_set_vector(enum arm64_hyp_spectre_vector slot);
int pkvm_create_mappings(void *from, void *to, enum kvm_pgtable_prot prot);
+int pkvm_create_mappings_locked(void *from, void *to, enum kvm_pgtable_prot prot);
int __pkvm_create_mappings(unsigned long start, unsigned long size,
unsigned long phys, enum kvm_pgtable_prot prot);
unsigned long __pkvm_create_private_mapping(phys_addr_t phys, size_t size,
diff --git a/arch/arm64/kvm/hyp/nvhe/mm.c b/arch/arm64/kvm/hyp/nvhe/mm.c
index a8efdf0f9003..256cbe5c0dca 100644
--- a/arch/arm64/kvm/hyp/nvhe/mm.c
+++ b/arch/arm64/kvm/hyp/nvhe/mm.c
@@ -67,7 +67,8 @@ unsigned long __pkvm_create_private_mapping(phys_addr_t phys, size_t size,
return addr;
}

-int pkvm_create_mappings(void *from, void *to, enum kvm_pgtable_prot prot)
+/* Must be called with the pkvm_pgd_lock held */
+int pkvm_create_mappings_locked(void *from, void *to, enum kvm_pgtable_prot prot)
{
unsigned long start = (unsigned long)from;
unsigned long end = (unsigned long)to;
@@ -81,7 +82,8 @@ int pkvm_create_mappings(void *from, void *to, enum kvm_pgtable_prot prot)
int err;

phys = hyp_virt_to_phys((void *)virt_addr);
- err = __pkvm_create_mappings(virt_addr, PAGE_SIZE, phys, prot);
+ err = kvm_pgtable_hyp_map(&pkvm_pgtable, virt_addr, PAGE_SIZE,
+ phys, prot);
if (err)
return err;
}
@@ -89,6 +91,17 @@ int pkvm_create_mappings(void *from, void *to, enum kvm_pgtable_prot prot)
return 0;
}

+int pkvm_create_mappings(void *from, void *to, enum kvm_pgtable_prot prot)
+{
+ int ret;
+
+ hyp_spin_lock(&pkvm_pgd_lock);
+ ret = pkvm_create_mappings_locked(from, to, prot);
+ hyp_spin_unlock(&pkvm_pgd_lock);
+
+ return ret;
+}
+
int hyp_back_vmemmap(phys_addr_t phys, unsigned long size, phys_addr_t back)
{
unsigned long start, end;
--
2.32.0.432.gabb21c7263-goog