[PATCH v3 05/10] RISC-V: KVM: Skeletal in-kernel AIA irqchip support

Anup Patel
2023-06-15T07:35:21Z

To incrementally implement in-kernel AIA irqchip support, we first
add minimal skeletal support which only compiles but does not provide
any functionality.

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Reviewed-by: Atish Patra <atishp@rivosinc.com>
---
arch/riscv/include/asm/kvm_aia.h | 20 +++++
arch/riscv/include/asm/kvm_host.h | 4 +
arch/riscv/include/uapi/asm/kvm.h | 4 +
arch/riscv/kvm/Kconfig | 4 +
arch/riscv/kvm/aia.c | 8 ++
arch/riscv/kvm/vm.c | 118 ++++++++++++++++++++++++++++++
6 files changed, 158 insertions(+)

diff --git a/arch/riscv/include/asm/kvm_aia.h b/arch/riscv/include/asm/kvm_aia.h
index 0938e0cadf80..3bc0a0e47a15 100644
--- a/arch/riscv/include/asm/kvm_aia.h
+++ b/arch/riscv/include/asm/kvm_aia.h
@@ -45,6 +45,7 @@ struct kvm_vcpu_aia {
#define irqchip_in_kernel(k) ((k)->arch.aia.in_kernel)

extern unsigned int kvm_riscv_aia_nr_hgei;
+extern unsigned int kvm_riscv_aia_max_ids;
DECLARE_STATIC_KEY_FALSE(kvm_riscv_aia_available);
#define kvm_riscv_aia_available() \
static_branch_unlikely(&kvm_riscv_aia_available)
@@ -116,6 +117,25 @@ static inline void kvm_riscv_vcpu_aia_deinit(struct kvm_vcpu *vcpu)
{
}

+static inline int kvm_riscv_aia_inject_msi_by_id(struct kvm *kvm,
+ u32 hart_index,
+ u32 guest_index, u32 iid)
+{
+ return 0;
+}
+
+static inline int kvm_riscv_aia_inject_msi(struct kvm *kvm,
+ struct kvm_msi *msi)
+{
+ return 0;
+}
+
+static inline int kvm_riscv_aia_inject_irq(struct kvm *kvm,
+ unsigned int irq, bool level)
+{
+ return 0;
+}
+
static inline void kvm_riscv_aia_init_vm(struct kvm *kvm)
{
}
diff --git a/arch/riscv/include/asm/kvm_host.h b/arch/riscv/include/asm/kvm_host.h
index ee0acccb1d3b..871432586a63 100644
--- a/arch/riscv/include/asm/kvm_host.h
+++ b/arch/riscv/include/asm/kvm_host.h
@@ -27,6 +27,8 @@

#define KVM_VCPU_MAX_FEATURES 0

+#define KVM_IRQCHIP_NUM_PINS 1024
+
#define KVM_REQ_SLEEP \
KVM_ARCH_REQ_FLAGS(0, KVM_REQUEST_WAIT | KVM_REQUEST_NO_WAKEUP)
#define KVM_REQ_VCPU_RESET KVM_ARCH_REQ(1)
@@ -318,6 +320,8 @@ int kvm_riscv_gstage_vmid_init(struct kvm *kvm);
bool kvm_riscv_gstage_vmid_ver_changed(struct kvm_vmid *vmid);
void kvm_riscv_gstage_vmid_update(struct kvm_vcpu *vcpu);

+int kvm_riscv_setup_default_irq_routing(struct kvm *kvm, u32 lines);
+
void __kvm_riscv_unpriv_trap(void);

unsigned long kvm_riscv_vcpu_unpriv_read(struct kvm_vcpu *vcpu,
diff --git a/arch/riscv/include/uapi/asm/kvm.h b/arch/riscv/include/uapi/asm/kvm.h
index f92790c9481a..332d4a274891 100644
--- a/arch/riscv/include/uapi/asm/kvm.h
+++ b/arch/riscv/include/uapi/asm/kvm.h
@@ -15,6 +15,7 @@
#include <asm/bitsperlong.h>
#include <asm/ptrace.h>

+#define __KVM_HAVE_IRQ_LINE
#define __KVM_HAVE_READONLY_MEM

#define KVM_COALESCED_MMIO_PAGE_OFFSET 1
@@ -203,6 +204,9 @@ enum KVM_RISCV_SBI_EXT_ID {
#define KVM_REG_RISCV_SBI_MULTI_REG_LAST \
KVM_REG_RISCV_SBI_MULTI_REG(KVM_RISCV_SBI_EXT_MAX - 1)

+/* One single KVM irqchip, ie. the AIA */
+#define KVM_NR_IRQCHIPS 1
+
#endif

#endif /* __LINUX_KVM_RISCV_H */
diff --git a/arch/riscv/kvm/Kconfig b/arch/riscv/kvm/Kconfig
index 28891e583259..dfc237d7875b 100644
--- a/arch/riscv/kvm/Kconfig
+++ b/arch/riscv/kvm/Kconfig
@@ -21,6 +21,10 @@ config KVM
tristate "Kernel-based Virtual Machine (KVM) support (EXPERIMENTAL)"
depends on RISCV_SBI && MMU
select HAVE_KVM_EVENTFD
+ select HAVE_KVM_IRQCHIP
+ select HAVE_KVM_IRQFD
+ select HAVE_KVM_IRQ_ROUTING
+ select HAVE_KVM_MSI
select HAVE_KVM_VCPU_ASYNC_IOCTL
select KVM_GENERIC_DIRTYLOG_READ_PROTECT
select KVM_GENERIC_HARDWARE_ENABLING
diff --git a/arch/riscv/kvm/aia.c b/arch/riscv/kvm/aia.c
index 3f97575707eb..18c442c15ff2 100644
--- a/arch/riscv/kvm/aia.c
+++ b/arch/riscv/kvm/aia.c
@@ -26,6 +26,7 @@ static DEFINE_PER_CPU(struct aia_hgei_control, aia_hgei);
static int hgei_parent_irq;

unsigned int kvm_riscv_aia_nr_hgei;
+unsigned int kvm_riscv_aia_max_ids;
DEFINE_STATIC_KEY_FALSE(kvm_riscv_aia_available);

static int aia_find_hgei(struct kvm_vcpu *owner)
@@ -618,6 +619,13 @@ int kvm_riscv_aia_init(void)
*/
kvm_riscv_aia_nr_hgei = 0;

+ /*
+ * Find number of guest MSI IDs
+ *
+ * TODO: To be updated later by AIA IMSIC HW guest file support
+ */
+ kvm_riscv_aia_max_ids = IMSIC_MAX_ID;
+
/* Initialize guest external interrupt line management */
rc = aia_hgei_init();
if (rc)
diff --git a/arch/riscv/kvm/vm.c b/arch/riscv/kvm/vm.c
index 6ef15f78e80f..7e2b50c692c1 100644
--- a/arch/riscv/kvm/vm.c
+++ b/arch/riscv/kvm/vm.c
@@ -55,11 +55,129 @@ void kvm_arch_destroy_vm(struct kvm *kvm)
kvm_riscv_aia_destroy_vm(kvm);
}

+int kvm_vm_ioctl_irq_line(struct kvm *kvm, struct kvm_irq_level *irql,
+ bool line_status)
+{
+ if (!irqchip_in_kernel(kvm))
+ return -ENXIO;
+
+ return kvm_riscv_aia_inject_irq(kvm, irql->irq, irql->level);
+}
+
+int kvm_set_msi(struct kvm_kernel_irq_routing_entry *e,
+ struct kvm *kvm, int irq_source_id,
+ int level, bool line_status)
+{
+ struct kvm_msi msi;
+
+ if (!level)
+ return -1;
+
+ msi.address_lo = e->msi.address_lo;
+ msi.address_hi = e->msi.address_hi;
+ msi.data = e->msi.data;
+ msi.flags = e->msi.flags;
+ msi.devid = e->msi.devid;
+
+ return kvm_riscv_aia_inject_msi(kvm, &msi);
+}
+
+static int kvm_riscv_set_irq(struct kvm_kernel_irq_routing_entry *e,
+ struct kvm *kvm, int irq_source_id,
+ int level, bool line_status)
+{
+ return kvm_riscv_aia_inject_irq(kvm, e->irqchip.pin, level);
+}
+
+int kvm_riscv_setup_default_irq_routing(struct kvm *kvm, u32 lines)
+{
+ struct kvm_irq_routing_entry *ents;
+ int i, rc;
+
+ ents = kcalloc(lines, sizeof(*ents), GFP_KERNEL);
+ if (!ents)
+ return -ENOMEM;
+
+ for (i = 0; i < lines; i++) {
+ ents[i].gsi = i;
+ ents[i].type = KVM_IRQ_ROUTING_IRQCHIP;
+ ents[i].u.irqchip.irqchip = 0;
+ ents[i].u.irqchip.pin = i;
+ }
+ rc = kvm_set_irq_routing(kvm, ents, lines, 0);
+ kfree(ents);
+
+ return rc;
+}
+
+bool kvm_arch_can_set_irq_routing(struct kvm *kvm)
+{
+ return irqchip_in_kernel(kvm);
+}
+
+int kvm_set_routing_entry(struct kvm *kvm,
+ struct kvm_kernel_irq_routing_entry *e,
+ const struct kvm_irq_routing_entry *ue)
+{
+ int r = -EINVAL;
+
+ switch (ue->type) {
+ case KVM_IRQ_ROUTING_IRQCHIP:
+ e->set = kvm_riscv_set_irq;
+ e->irqchip.irqchip = ue->u.irqchip.irqchip;
+ e->irqchip.pin = ue->u.irqchip.pin;
+ if ((e->irqchip.pin >= KVM_IRQCHIP_NUM_PINS) ||
+ (e->irqchip.irqchip >= KVM_NR_IRQCHIPS))
+ goto out;
+ break;
+ case KVM_IRQ_ROUTING_MSI:
+ e->set = kvm_set_msi;
+ e->msi.address_lo = ue->u.msi.address_lo;
+ e->msi.address_hi = ue->u.msi.address_hi;
+ e->msi.data = ue->u.msi.data;
+ e->msi.flags = ue->flags;
+ e->msi.devid = ue->u.msi.devid;
+ break;
+ default:
+ goto out;
+ }
+ r = 0;
+out:
+ return r;
+}
+
+int kvm_arch_set_irq_inatomic(struct kvm_kernel_irq_routing_entry *e,
+ struct kvm *kvm, int irq_source_id, int level,
+ bool line_status)
+{
+ if (!level)
+ return -EWOULDBLOCK;
+
+ switch (e->type) {
+ case KVM_IRQ_ROUTING_MSI:
+ return kvm_set_msi(e, kvm, irq_source_id, level, line_status);
+
+ case KVM_IRQ_ROUTING_IRQCHIP:
+ return kvm_riscv_set_irq(e, kvm, irq_source_id,
+ level, line_status);
+ }
+
+ return -EWOULDBLOCK;
+}
+
+bool kvm_arch_irqchip_in_kernel(struct kvm *kvm)
+{
+ return irqchip_in_kernel(kvm);
+}
+
int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
{
int r;

switch (ext) {
+ case KVM_CAP_IRQCHIP:
+ r = kvm_riscv_aia_available();
+ break;
case KVM_CAP_IOEVENTFD:
case KVM_CAP_DEVICE_CTRL:
case KVM_CAP_USER_MEMORY:
--
2.34.1