Populate bits [56:55] of the leaf entry with the level provided
by the guest's S2 translation.
Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
---
arch/arm64/include/asm/kvm_nested.h | 7 +++++++
arch/arm64/kvm/mmu.c | 16 ++++++++++++++--
2 files changed, 21 insertions(+), 2 deletions(-)
diff --git a/arch/arm64/include/asm/kvm_nested.h b/arch/arm64/include/asm/kvm_nested.h
index 52d0a6c0fecc..784168dcb0fe 100644
--- a/arch/arm64/include/asm/kvm_nested.h
+++ b/arch/arm64/include/asm/kvm_nested.h
@@ -5,6 +5,8 @@
#include <linux/bitfield.h>
#include <linux/kvm_host.h>
+#include <asm/kvm_pgtable.h>
+
static inline bool vcpu_has_nv(const struct kvm_vcpu *vcpu)
{
return (!__is_defined(__KVM_NVHE_HYPERVISOR__) &&
@@ -139,4 +141,9 @@ void access_nested_id_reg(struct kvm_vcpu *v, struct sys_reg_params *p,
#define KVM_NV_GUEST_MAP_SZ (KVM_PGTABLE_PROT_SW1 | KVM_PGTABLE_PROT_SW0)
+static inline u64 kvm_encode_nested_level(struct kvm_s2_trans *trans)
+{
+ return FIELD_PREP(KVM_NV_GUEST_MAP_SZ, trans->level);
+}
+
#endif /* __ARM64_KVM_NESTED_H */
diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index 7fd122d687f7..42bce05261c5 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -1456,11 +1456,17 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
* Potentially reduce shadow S2 permissions to match the guest's own
* S2. For exec faults, we'd only reach this point if the guest
* actually allowed it (see kvm_s2_handle_perm_fault).
+ *
+ * Also encode the level of the nested translation in the SW bits of
+ * the PTE/PMD/PUD. This will be retrived on TLB invalidation from
+ * the guest.
*/
if (nested) {
writable &= kvm_s2_trans_writable(nested);
if (!kvm_s2_trans_readable(nested))
prot &= ~KVM_PGTABLE_PROT_R;
+
+ prot |= kvm_encode_nested_level(nested);
}
read_lock(&kvm->mmu_lock);
@@ -1514,14 +1520,20 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
* permissions only if vma_pagesize equals fault_granule. Otherwise,
* kvm_pgtable_stage2_map() should be called to change block size.
*/
- if (fault_status == ESR_ELx_FSC_PERM && vma_pagesize == fault_granule)
+ if (fault_status == ESR_ELx_FSC_PERM && vma_pagesize == fault_granule) {
+ /*
+ * Drop the SW bits in favour of those stored in the
+ * PTE, which will be preserved.
+ */
+ prot &= ~KVM_NV_GUEST_MAP_SZ;
ret = kvm_pgtable_stage2_relax_perms(pgt, fault_ipa, prot);
- else
+ } else {
ret = kvm_pgtable_stage2_map(pgt, fault_ipa, vma_pagesize,
__pfn_to_phys(pfn), prot,
memcache,
KVM_PGTABLE_WALK_HANDLE_FAULT |
KVM_PGTABLE_WALK_SHARED);
+ }
/* Mark the page dirty only if the fault is handled successfully */
if (writable && !ret) {
--
2.34.1
