[RFC PATCH 10/15] RISC-V: KVM: Add irqbypass skeleton

Andrew Jones
2024-11-14T16:19:15Z

Add all the functions needed to wire up irqbypass support.
kvm_arch_update_irqfd_routing() is left unimplemented, so return
false from kvm_arch_has_irq_bypass().

Signed-off-by: Andrew Jones <ajones@ventanamicro.com>
---
arch/riscv/include/asm/kvm_host.h | 3 ++
arch/riscv/kvm/Kconfig | 1 +
arch/riscv/kvm/aia_imsic.c | 6 ++++
arch/riscv/kvm/vm.c | 60 +++++++++++++++++++++++++++++++
4 files changed, 70 insertions(+)

diff --git a/arch/riscv/include/asm/kvm_host.h b/arch/riscv/include/asm/kvm_host.h
index 35eab6e0f4ae..fef7422939f6 100644
--- a/arch/riscv/include/asm/kvm_host.h
+++ b/arch/riscv/include/asm/kvm_host.h
@@ -114,6 +114,9 @@ struct kvm_arch {

/* AIA Guest/VM context */
struct kvm_aia aia;
+
+#define __KVM_HAVE_ARCH_ASSIGNED_DEVICE
+ atomic_t assigned_device_count;
};

struct kvm_cpu_trap {
diff --git a/arch/riscv/kvm/Kconfig b/arch/riscv/kvm/Kconfig
index 333d95da8ebe..9a4feb1e671d 100644
--- a/arch/riscv/kvm/Kconfig
+++ b/arch/riscv/kvm/Kconfig
@@ -21,6 +21,7 @@ config KVM
tristate "Kernel-based Virtual Machine (KVM) support (EXPERIMENTAL)"
depends on RISCV_SBI && MMU
select HAVE_KVM_IRQCHIP
+ select HAVE_KVM_IRQ_BYPASS
select HAVE_KVM_IRQ_ROUTING
select HAVE_KVM_MSI
select HAVE_KVM_VCPU_ASYNC_IOCTL
diff --git a/arch/riscv/kvm/aia_imsic.c b/arch/riscv/kvm/aia_imsic.c
index a8085cd8215e..64b1f3713dd5 100644
--- a/arch/riscv/kvm/aia_imsic.c
+++ b/arch/riscv/kvm/aia_imsic.c
@@ -727,6 +727,12 @@ void kvm_riscv_vcpu_aia_imsic_release(struct kvm_vcpu *vcpu)
kvm_riscv_aia_free_hgei(old_vsfile_cpu, old_vsfile_hgei);
}

+int kvm_arch_update_irqfd_routing(struct kvm *kvm, unsigned int host_irq,
+ uint32_t guest_irq, bool set)
+{
+ return -ENXIO;
+}
+
int kvm_riscv_vcpu_aia_imsic_update(struct kvm_vcpu *vcpu)
{
unsigned long flags;
diff --git a/arch/riscv/kvm/vm.c b/arch/riscv/kvm/vm.c
index 7396b8654f45..9c5837518c1a 100644
--- a/arch/riscv/kvm/vm.c
+++ b/arch/riscv/kvm/vm.c
@@ -11,6 +11,9 @@
#include <linux/module.h>
#include <linux/uaccess.h>
#include <linux/kvm_host.h>
+#include <linux/kvm_irqfd.h>
+
+#include <asm/kvm_aia.h>

const struct _kvm_stats_desc kvm_vm_stats_desc[] = {
KVM_GENERIC_VM_STATS()
@@ -55,6 +58,63 @@ void kvm_arch_destroy_vm(struct kvm *kvm)
kvm_riscv_aia_destroy_vm(kvm);
}

+void kvm_arch_start_assignment(struct kvm *kvm)
+{
+ atomic_inc(&kvm->arch.assigned_device_count);
+}
+EXPORT_SYMBOL_GPL(kvm_arch_start_assignment);
+
+void kvm_arch_end_assignment(struct kvm *kvm)
+{
+ atomic_dec(&kvm->arch.assigned_device_count);
+}
+EXPORT_SYMBOL_GPL(kvm_arch_end_assignment);
+
+bool noinstr kvm_arch_has_assigned_device(struct kvm *kvm)
+{
+ return arch_atomic_read(&kvm->arch.assigned_device_count);
+}
+EXPORT_SYMBOL_GPL(kvm_arch_has_assigned_device);
+
+bool kvm_arch_has_irq_bypass(void)
+{
+ return false;
+}
+
+int kvm_arch_irq_bypass_add_producer(struct irq_bypass_consumer *cons,
+ struct irq_bypass_producer *prod)
+{
+ struct kvm_kernel_irqfd *irqfd =
+ container_of(cons, struct kvm_kernel_irqfd, consumer);
+ int ret;
+
+ irqfd->producer = prod;
+ kvm_arch_start_assignment(irqfd->kvm);
+ ret = kvm_arch_update_irqfd_routing(irqfd->kvm, prod->irq, irqfd->gsi, true);
+ if (ret)
+ kvm_arch_end_assignment(irqfd->kvm);
+
+ return ret;
+}
+
+void kvm_arch_irq_bypass_del_producer(struct irq_bypass_consumer *cons,
+ struct irq_bypass_producer *prod)
+{
+ struct kvm_kernel_irqfd *irqfd =
+ container_of(cons, struct kvm_kernel_irqfd, consumer);
+ int ret;
+
+ WARN_ON(irqfd->producer != prod);
+ irqfd->producer = NULL;
+
+ ret = kvm_arch_update_irqfd_routing(irqfd->kvm, prod->irq, irqfd->gsi, false);
+ if (ret)
+ pr_info("irq bypass consumer (token %p) unregistration fails: %d\n",
+ irqfd->consumer.token, ret);
+
+ kvm_arch_end_assignment(irqfd->kvm);
+}
+
int kvm_vm_ioctl_irq_line(struct kvm *kvm, struct kvm_irq_level *irql,
bool line_status)
{
--
2.47.0