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Message-ID: <20250821210042.3451147-4-seanjc@google.com>
Date: Thu, 21 Aug 2025 14:00:29 -0700
From: Sean Christopherson <seanjc@...gle.com>
To: Marc Zyngier <maz@...nel.org>, Oliver Upton <oliver.upton@...ux.dev>
Cc: linux-arm-kernel@...ts.infradead.org, kvmarm@...ts.linux.dev,
linux-kernel@...r.kernel.org, Sean Christopherson <seanjc@...gle.com>,
James Houghton <jthoughton@...gle.com>
Subject: [RFC PATCH 03/16] KVM: arm64: Move SRCU-protected region of
kvm_handle_guest_abort() to helper
Move the SRCU-protected portion of the abort handler to a separate helper
in anticipation of adding "struct kvm_page_fault" to track state related
to resolving the fault. Using a separate helper will allow making several
fields in kvm_page_fault "const", without having to do something funky
like create a temporary copy in the middle of kvm_handle_guest_abort().
No functional change intended.
Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
arch/arm64/kvm/mmu.c | 172 ++++++++++++++++++++++---------------------
1 file changed, 88 insertions(+), 84 deletions(-)
diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index 1e3ac283c519..de028471b9eb 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -1811,82 +1811,16 @@ static void handle_access_fault(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa)
read_unlock(&vcpu->kvm->mmu_lock);
}
-/**
- * kvm_handle_guest_abort - handles all 2nd stage aborts
- * @vcpu: the VCPU pointer
- *
- * Any abort that gets to the host is almost guaranteed to be caused by a
- * missing second stage translation table entry, which can mean that either the
- * guest simply needs more memory and we must allocate an appropriate page or it
- * can mean that the guest tried to access I/O memory, which is emulated by user
- * space. The distinction is based on the IPA causing the fault and whether this
- * memory region has been registered as standard RAM by user space.
- */
-int kvm_handle_guest_abort(struct kvm_vcpu *vcpu)
+static int __kvm_handle_guest_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
+ unsigned long esr)
{
struct kvm_s2_trans nested_trans, *nested = NULL;
- unsigned long esr;
- phys_addr_t fault_ipa; /* The address we faulted on */
- phys_addr_t ipa; /* Always the IPA in the L1 guest phys space */
struct kvm_memory_slot *memslot;
- unsigned long hva;
bool write_fault, writable;
+ unsigned long hva;
+ phys_addr_t ipa; /* Always the IPA in the L1 guest phys space */
gfn_t gfn;
- int ret, idx;
-
- /* Synchronous External Abort? */
- if (kvm_vcpu_abt_issea(vcpu)) {
- /*
- * For RAS the host kernel may handle this abort.
- * There is no need to pass the error into the guest.
- */
- if (kvm_handle_guest_sea())
- return kvm_inject_serror(vcpu);
-
- return 1;
- }
-
- esr = kvm_vcpu_get_esr(vcpu);
-
- /*
- * The fault IPA should be reliable at this point as we're not dealing
- * with an SEA.
- */
- ipa = fault_ipa = kvm_vcpu_get_fault_ipa(vcpu);
- if (KVM_BUG_ON(ipa == INVALID_GPA, vcpu->kvm))
- return -EFAULT;
-
- if (esr_fsc_is_translation_fault(esr)) {
- /* Beyond sanitised PARange (which is the IPA limit) */
- if (fault_ipa >= BIT_ULL(get_kvm_ipa_limit())) {
- kvm_inject_size_fault(vcpu);
- return 1;
- }
-
- /* Falls between the IPA range and the PARange? */
- if (fault_ipa >= BIT_ULL(VTCR_EL2_IPA(vcpu->arch.hw_mmu->vtcr))) {
- fault_ipa |= kvm_vcpu_get_hfar(vcpu) & GENMASK(11, 0);
-
- return kvm_inject_sea(vcpu, kvm_vcpu_trap_is_iabt(vcpu),
- fault_ipa);
- }
- }
-
- trace_kvm_guest_fault(*vcpu_pc(vcpu), kvm_vcpu_get_esr(vcpu),
- kvm_vcpu_get_hfar(vcpu), fault_ipa);
-
- /* Check the stage-2 fault is trans. fault or write fault */
- if (!esr_fsc_is_translation_fault(esr) &&
- !esr_fsc_is_permission_fault(esr) &&
- !esr_fsc_is_access_flag_fault(esr)) {
- kvm_err("Unsupported FSC: EC=%#x xFSC=%#lx ESR_EL2=%#lx\n",
- kvm_vcpu_trap_get_class(vcpu),
- (unsigned long)kvm_vcpu_trap_get_fault(vcpu),
- (unsigned long)kvm_vcpu_get_esr(vcpu));
- return -EFAULT;
- }
-
- idx = srcu_read_lock(&vcpu->kvm->srcu);
+ int ret;
/*
* We may have faulted on a shadow stage 2 page table if we are
@@ -1906,13 +1840,13 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu)
ret = kvm_walk_nested_s2(vcpu, fault_ipa, &nested_trans);
if (ret) {
kvm_inject_s2_fault(vcpu, kvm_s2_trans_esr(&nested_trans));
- goto out_unlock;
+ return ret;
}
ret = kvm_s2_handle_perm_fault(vcpu, &nested_trans);
if (ret) {
kvm_inject_s2_fault(vcpu, kvm_s2_trans_esr(&nested_trans));
- goto out_unlock;
+ return ret;
}
ipa = kvm_s2_trans_output(&nested_trans);
@@ -1935,10 +1869,8 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu)
goto out;
}
- if (kvm_vcpu_abt_iss1tw(vcpu)) {
- ret = kvm_inject_sea_dabt(vcpu, kvm_vcpu_get_hfar(vcpu));
- goto out_unlock;
- }
+ if (kvm_vcpu_abt_iss1tw(vcpu))
+ return kvm_inject_sea_dabt(vcpu, kvm_vcpu_get_hfar(vcpu));
/*
* Check for a cache maintenance operation. Since we
@@ -1952,8 +1884,7 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu)
*/
if (kvm_is_error_hva(hva) && kvm_vcpu_dabt_is_cm(vcpu)) {
kvm_incr_pc(vcpu);
- ret = 1;
- goto out_unlock;
+ return 1;
}
/*
@@ -1963,8 +1894,7 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu)
* of the page size.
*/
ipa |= kvm_vcpu_get_hfar(vcpu) & GENMASK(11, 0);
- ret = io_mem_abort(vcpu, ipa);
- goto out_unlock;
+ return io_mem_abort(vcpu, ipa);
}
/* Userspace should not be able to register out-of-bounds IPAs */
@@ -1972,8 +1902,7 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu)
if (esr_fsc_is_access_flag_fault(esr)) {
handle_access_fault(vcpu, fault_ipa);
- ret = 1;
- goto out_unlock;
+ return 1;
}
ret = user_mem_abort(vcpu, fault_ipa, nested, memslot, hva,
@@ -1983,7 +1912,82 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu)
out:
if (ret == -ENOEXEC)
ret = kvm_inject_sea_iabt(vcpu, kvm_vcpu_get_hfar(vcpu));
-out_unlock:
+ return ret;
+}
+
+/**
+ * kvm_handle_guest_abort - handles all 2nd stage aborts
+ * @vcpu: the VCPU pointer
+ *
+ * Any abort that gets to the host is almost guaranteed to be caused by a
+ * missing second stage translation table entry, which can mean that either the
+ * guest simply needs more memory and we must allocate an appropriate page or it
+ * can mean that the guest tried to access I/O memory, which is emulated by user
+ * space. The distinction is based on the IPA causing the fault and whether this
+ * memory region has been registered as standard RAM by user space.
+ */
+int kvm_handle_guest_abort(struct kvm_vcpu *vcpu)
+{
+ unsigned long esr;
+ phys_addr_t fault_ipa; /* The address we faulted on */
+ int ret, idx;
+
+ /* Synchronous External Abort? */
+ if (kvm_vcpu_abt_issea(vcpu)) {
+ /*
+ * For RAS the host kernel may handle this abort.
+ * There is no need to pass the error into the guest.
+ */
+ if (kvm_handle_guest_sea())
+ return kvm_inject_serror(vcpu);
+
+ return 1;
+ }
+
+ esr = kvm_vcpu_get_esr(vcpu);
+
+ /*
+ * The fault IPA should be reliable at this point as we're not dealing
+ * with an SEA.
+ */
+ fault_ipa = kvm_vcpu_get_fault_ipa(vcpu);
+ if (KVM_BUG_ON(fault_ipa == INVALID_GPA, vcpu->kvm))
+ return -EFAULT;
+
+ if (esr_fsc_is_translation_fault(esr)) {
+ /* Beyond sanitised PARange (which is the IPA limit) */
+ if (fault_ipa >= BIT_ULL(get_kvm_ipa_limit())) {
+ kvm_inject_size_fault(vcpu);
+ return 1;
+ }
+
+ /* Falls between the IPA range and the PARange? */
+ if (fault_ipa >= BIT_ULL(VTCR_EL2_IPA(vcpu->arch.hw_mmu->vtcr))) {
+ fault_ipa |= kvm_vcpu_get_hfar(vcpu) & GENMASK(11, 0);
+
+ return kvm_inject_sea(vcpu, kvm_vcpu_trap_is_iabt(vcpu),
+ fault_ipa);
+ }
+ }
+
+ trace_kvm_guest_fault(*vcpu_pc(vcpu), kvm_vcpu_get_esr(vcpu),
+ kvm_vcpu_get_hfar(vcpu), fault_ipa);
+
+ /* Check the stage-2 fault is trans. fault or write fault */
+ if (!esr_fsc_is_translation_fault(esr) &&
+ !esr_fsc_is_permission_fault(esr) &&
+ !esr_fsc_is_access_flag_fault(esr)) {
+ kvm_err("Unsupported FSC: EC=%#x xFSC=%#lx ESR_EL2=%#lx\n",
+ kvm_vcpu_trap_get_class(vcpu),
+ (unsigned long)kvm_vcpu_trap_get_fault(vcpu),
+ (unsigned long)kvm_vcpu_get_esr(vcpu));
+ return -EFAULT;
+ }
+
+ idx = srcu_read_lock(&vcpu->kvm->srcu);
+
+ ret = __kvm_handle_guest_abort(vcpu, fault_ipa, esr);
+
srcu_read_unlock(&vcpu->kvm->srcu, idx);
return ret;
}
--
2.51.0.261.g7ce5a0a67e-goog
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