[PATCH v4 13/21] KVM: arm64: Impment SDEI event delivery

Gavin Shan
2021-08-15T00:15:46Z

This implement kvm_sdei_deliver() to support SDEI event delivery.
The function is called when the request (KVM_REQ_SDEI) is raised.
The following rules are taken according to the SDEI specification:

* x0 - x17 are saved. All of them are cleared except the following
registered:
x0: number SDEI event to be delivered
x1: parameter associated with the SDEI event
x2: PC of the interrupted context
x3: PState of the interrupted context

* PC is set to the handler of the SDEI event, which was provided
during its registration. PState is modified accordingly.

* SDEI event with critical priority can preempt those with normal
priority.

Signed-off-by: Gavin Shan <gshan@redhat.com>
---
arch/arm64/include/asm/kvm_host.h | 1 +
arch/arm64/include/asm/kvm_sdei.h | 1 +
arch/arm64/kvm/arm.c | 3 ++
arch/arm64/kvm/sdei.c | 84 +++++++++++++++++++++++++++++++
4 files changed, 89 insertions(+)

diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index aedf901e1ec7..46f363aa6524 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -47,6 +47,7 @@
#define KVM_REQ_RECORD_STEAL KVM_ARCH_REQ(3)
#define KVM_REQ_RELOAD_GICv4 KVM_ARCH_REQ(4)
#define KVM_REQ_RELOAD_PMU KVM_ARCH_REQ(5)
+#define KVM_REQ_SDEI KVM_ARCH_REQ(6)

#define KVM_DIRTY_LOG_MANUAL_CAPS (KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE | \
KVM_DIRTY_LOG_INITIALLY_SET)
diff --git a/arch/arm64/include/asm/kvm_sdei.h b/arch/arm64/include/asm/kvm_sdei.h
index b0abc13a0256..7f5f5ad689e6 100644
--- a/arch/arm64/include/asm/kvm_sdei.h
+++ b/arch/arm64/include/asm/kvm_sdei.h
@@ -112,6 +112,7 @@ KVM_SDEI_FLAG_FUNC(enabled)
void kvm_sdei_init_vm(struct kvm *kvm);
void kvm_sdei_create_vcpu(struct kvm_vcpu *vcpu);
int kvm_sdei_hypercall(struct kvm_vcpu *vcpu);
+void kvm_sdei_deliver(struct kvm_vcpu *vcpu);
void kvm_sdei_destroy_vcpu(struct kvm_vcpu *vcpu);
void kvm_sdei_destroy_vm(struct kvm *kvm);

diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 2f021aa41632..0c3db1ef1ba9 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -689,6 +689,9 @@ static void check_vcpu_requests(struct kvm_vcpu *vcpu)
if (kvm_check_request(KVM_REQ_VCPU_RESET, vcpu))
kvm_reset_vcpu(vcpu);

+ if (kvm_check_request(KVM_REQ_SDEI, vcpu))
+ kvm_sdei_deliver(vcpu);
+
/*
* Clear IRQ_PENDING requests that were made to guarantee
* that a VCPU sees new virtual interrupts.
diff --git a/arch/arm64/kvm/sdei.c b/arch/arm64/kvm/sdei.c
index 62efee2b67b8..b5d6d1ed3858 100644
--- a/arch/arm64/kvm/sdei.c
+++ b/arch/arm64/kvm/sdei.c
@@ -671,6 +671,90 @@ int kvm_sdei_hypercall(struct kvm_vcpu *vcpu)
return 1;
}

+void kvm_sdei_deliver(struct kvm_vcpu *vcpu)
+{
+ struct kvm *kvm = vcpu->kvm;
+ struct kvm_sdei_kvm *ksdei = kvm->arch.sdei;
+ struct kvm_sdei_vcpu *vsdei = vcpu->arch.sdei;
+ struct kvm_sdei_event *kse = NULL;
+ struct kvm_sdei_kvm_event *kske = NULL;
+ struct kvm_sdei_vcpu_event *ksve = NULL;
+ struct kvm_sdei_vcpu_regs *regs = NULL;
+ unsigned long pstate;
+ int index = 0;
+
+ /* Sanity check */
+ if (!(ksdei && vsdei))
+ return;
+
+ /* The critical event can't be preempted */
+ spin_lock(&vsdei->lock);
+ if (vsdei->critical_event)
+ goto unlock;
+
+ /*
+ * The normal event can be preempted by the critical event.
+ * However, the normal event can't be preempted by another
+ * normal event.
+ */
+ ksve = list_first_entry_or_null(&vsdei->critical_events,
+ struct kvm_sdei_vcpu_event, link);
+ if (!ksve && !vsdei->normal_event) {
+ ksve = list_first_entry_or_null(&vsdei->normal_events,
+ struct kvm_sdei_vcpu_event, link);
+ }
+
+ if (!ksve)
+ goto unlock;
+
+ kske = ksve->kske;
+ kse = kske->kse;
+ if (kse->state.priority == SDEI_EVENT_PRIORITY_CRITICAL) {
+ vsdei->critical_event = ksve;
+ vsdei->state.critical_num = ksve->state.num;
+ regs = &vsdei->state.critical_regs;
+ } else {
+ vsdei->normal_event = ksve;
+ vsdei->state.normal_num = ksve->state.num;
+ regs = &vsdei->state.normal_regs;
+ }
+
+ /* Save registers: x0 -> x17, PC, PState */
+ for (index = 0; index < ARRAY_SIZE(regs->regs); index++)
+ regs->regs[index] = vcpu_get_reg(vcpu, index);
+
+ regs->pc = *vcpu_pc(vcpu);
+ regs->pstate = *vcpu_cpsr(vcpu);
+
+ /*
+ * Inject SDEI event: x0 -> x3, PC, PState. We needn't take lock
+ * for the KVM event as it can't be destroyed because of its
+ * reference count.
+ */
+ for (index = 0; index < ARRAY_SIZE(regs->regs); index++)
+ vcpu_set_reg(vcpu, index, 0);
+
+ index = (kse->state.type == SDEI_EVENT_TYPE_PRIVATE) ?
+ vcpu->vcpu_idx : 0;
+ vcpu_set_reg(vcpu, 0, kske->state.num);
+ vcpu_set_reg(vcpu, 1, kske->state.params[index]);
+ vcpu_set_reg(vcpu, 2, regs->pc);
+ vcpu_set_reg(vcpu, 3, regs->pstate);
+
+ pstate = regs->pstate;
+ pstate |= (PSR_D_BIT | PSR_A_BIT | PSR_I_BIT | PSR_F_BIT);
+ pstate &= ~PSR_MODE_MASK;
+ pstate |= PSR_MODE_EL1h;
+ pstate &= ~PSR_MODE32_BIT;
+
+ vcpu_write_sys_reg(vcpu, regs->pstate, SPSR_EL1);
+ *vcpu_cpsr(vcpu) = pstate;
+ *vcpu_pc(vcpu) = kske->state.entries[index];
+
+unlock:
+ spin_unlock(&vsdei->lock);
+}
+
void kvm_sdei_init_vm(struct kvm *kvm)
{
struct kvm_sdei_kvm *ksdei;
--
2.23.0