[PATCH v3 04/14] KVM: arm64: Propagate and use esr in s2fd when handling guest aborts

[Lorenzo Stoakes (ARM)]

kvm_handle_guest_abort() establishes a kvm_s2_fault_desc data structure,
s2fd, to store and propagate state to either pkvm_mem_abort(), gmem_abort()
or user_mem_abort() handlers.

Each of these, however, examines the Exception Syndrome Register (ESR) via
s2fd->vcpu.

Introduce an s2fd->esr field to abstract this and propagate it to callers.

The value of this (beyond refactoring) is to be able to later generate
faults with a synthetic esr, specifically to implement stage 2 page table
pre-faulting.

Abort handlers which use kvm_s2_fault_desc - gmem_abort() and
user_mem_abort() - now only reference s2fd->esr and do not look it up in
any other way, which makes it safe to pass a synthetic s2fd->esr value to
these functions.

No functional change intended.

Signed-off-by: Lorenzo Stoakes (ARM) <ljs at kernel.org>
---
 arch/arm64/kvm/mmu.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index d8b11817a45f..3cd4dd6478db 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -1655,21 +1655,22 @@ struct kvm_s2_fault_desc {
 	struct kvm_s2_trans	*nested;
 	struct kvm_memory_slot	*memslot;
 	unsigned long		hva;
+	unsigned long		esr;
 };
 
 static bool kvm_s2_fault_is_perm(const struct kvm_s2_fault_desc *s2fd)
 {
-	return esr_fsc_is_permission_fault(kvm_vcpu_get_esr(s2fd->vcpu));
+	return esr_fsc_is_permission_fault(s2fd->esr);
 }
 
 static bool kvm_s2_fault_is_exec(const struct kvm_s2_fault_desc *s2fd)
 {
-	return esr_abt_is_exec_fault(kvm_vcpu_get_esr(s2fd->vcpu));
+	return esr_abt_is_exec_fault(s2fd->esr);
 }
 
 static bool kvm_s2_fault_is_write(const struct kvm_s2_fault_desc *s2fd)
 {
-	return esr_abt_is_write_fault(kvm_vcpu_get_esr(s2fd->vcpu));
+	return esr_abt_is_write_fault(s2fd->esr);
 }
 
 static u64 kvm_s2_perm_fault_granule(const struct kvm_s2_fault_desc *s2fd)
@@ -1678,7 +1679,7 @@ static u64 kvm_s2_perm_fault_granule(const struct kvm_s2_fault_desc *s2fd)
 
 	if (!kvm_s2_fault_is_perm(s2fd))
 		return 0;
-	level = kvm_vcpu_get_esr(s2fd->vcpu) & ESR_ELx_FSC_LEVEL;
+	level = s2fd->esr & ESR_ELx_FSC_LEVEL;
 	return BIT(ARM64_HW_PGTABLE_LEVEL_SHIFT(level));
 }
 
@@ -2067,7 +2068,7 @@ static int kvm_s2_fault_compute_prot(const struct kvm_s2_fault_desc *s2fd,
 	 * and trigger the exception here. Since the memslot is valid, inject
 	 * the fault back to the guest.
 	 */
-	if (esr_fsc_is_excl_atomic_fault(kvm_vcpu_get_esr(s2fd->vcpu))) {
+	if (esr_fsc_is_excl_atomic_fault(s2fd->esr)) {
 		kvm_inject_dabt_excl_atomic(s2fd->vcpu, kvm_vcpu_get_hfar(s2fd->vcpu));
 		return 1;
 	}
@@ -2518,6 +2519,7 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu)
 		.nested		= nested,
 		.memslot	= memslot,
 		.hva		= hva,
+		.esr		= esr,
 	};
 
 	if (kvm_vm_is_protected(vcpu->kvm)) {

-- 
2.55.0