Add the infrastructure for exception handling in riscv selftests.
Currently, the guest_unexp_trap handler was used by default, which
aborts the test. Customized handlers can be enabled by calling
vm_install_exception_handler(vector) or vm_install_interrupt_handler().
The code is inspired from that of x86/arm64.
Signed-off-by: Haibo Xu <haibo1.xu@xxxxxxxxx>
---
tools/testing/selftests/kvm/Makefile | 1 +
.../selftests/kvm/include/riscv/processor.h | 49 +++++++++
.../selftests/kvm/lib/riscv/handlers.S | 101 ++++++++++++++++++
.../selftests/kvm/lib/riscv/processor.c | 57 ++++++++++
4 files changed, 208 insertions(+)
create mode 100644 tools/testing/selftests/kvm/lib/riscv/handlers.S
diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
index c692cc86e7da..70f3a5ba991e 100644
--- a/tools/testing/selftests/kvm/Makefile
+++ b/tools/testing/selftests/kvm/Makefile
@@ -52,6 +52,7 @@ LIBKVM_s390x += lib/s390x/diag318_test_handler.c
LIBKVM_s390x += lib/s390x/processor.c
LIBKVM_s390x += lib/s390x/ucall.c
+LIBKVM_riscv += lib/riscv/handlers.S
LIBKVM_riscv += lib/riscv/processor.c
LIBKVM_riscv += lib/riscv/ucall.c
diff --git a/tools/testing/selftests/kvm/include/riscv/processor.h b/tools/testing/selftests/kvm/include/riscv/processor.h
index d00d213c3805..9ea6e7bedc61 100644
--- a/tools/testing/selftests/kvm/include/riscv/processor.h
+++ b/tools/testing/selftests/kvm/include/riscv/processor.h
@@ -9,6 +9,7 @@
#include "kvm_util.h"
#include <linux/stringify.h>
+#include <asm/csr.h>
static inline uint64_t __kvm_reg_id(uint64_t type, uint64_t idx,
uint64_t size)
@@ -38,6 +39,54 @@ static inline uint64_t __kvm_reg_id(uint64_t type, uint64_t idx,
KVM_REG_RISCV_TIMER_REG(name), \
KVM_REG_SIZE_U64)
+struct ex_regs {
+ unsigned long ra;
+ unsigned long sp;
+ unsigned long gp;
+ unsigned long tp;
+ unsigned long t0;
+ unsigned long t1;
+ unsigned long t2;
+ unsigned long s0;
+ unsigned long s1;
+ unsigned long a0;
+ unsigned long a1;
+ unsigned long a2;
+ unsigned long a3;
+ unsigned long a4;
+ unsigned long a5;
+ unsigned long a6;
+ unsigned long a7;
+ unsigned long s2;
+ unsigned long s3;
+ unsigned long s4;
+ unsigned long s5;
+ unsigned long s6;
+ unsigned long s7;
+ unsigned long s8;
+ unsigned long s9;
+ unsigned long s10;
+ unsigned long s11;
+ unsigned long t3;
+ unsigned long t4;
+ unsigned long t5;
+ unsigned long t6;
+ unsigned long epc;
+ unsigned long status;
+ unsigned long cause;
+};
+
+#define VECTOR_NUM 2
+#define EC_NUM 32
+#define EC_MASK (EC_NUM - 1)
+
+void vm_init_trap_vector_tables(struct kvm_vm *vm);
+void vcpu_init_trap_vector_tables(struct kvm_vcpu *vcpu);
+
+typedef void(*handler_fn)(struct ex_regs *);
+void vm_install_exception_handler(struct kvm_vm *vm, int ec, handler_fn handler);
+void vm_install_interrupt_handler(struct kvm_vm *vm, handler_fn handler);
+
/* L3 index Bit[47:39] */
#define PGTBL_L3_INDEX_MASK 0x0000FF8000000000ULL
#define PGTBL_L3_INDEX_SHIFT 39
diff --git a/tools/testing/selftests/kvm/lib/riscv/handlers.S b/tools/testing/selftests/kvm/lib/riscv/handlers.S
new file mode 100644
index 000000000000..ce0b1d5415b9
--- /dev/null
+++ b/tools/testing/selftests/kvm/lib/riscv/handlers.S
@@ -0,0 +1,101 @@
+// SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2023 Intel Corporation
+ */
+
+#include <asm/csr.h>
+
+.macro save_context
+ addi sp, sp, (-8*34)
+
+ sd x1, 0(sp)
+ sd x2, 8(sp)
+ sd x3, 16(sp)
+ sd x4, 24(sp)
+ sd x5, 32(sp)
+ sd x6, 40(sp)
+ sd x7, 48(sp)
+ sd x8, 56(sp)
+ sd x9, 64(sp)
+ sd x10, 72(sp)
+ sd x11, 80(sp)
+ sd x12, 88(sp)
+ sd x13, 96(sp)
+ sd x14, 104(sp)
+ sd x15, 112(sp)
+ sd x16, 120(sp)
+ sd x17, 128(sp)
+ sd x18, 136(sp)
+ sd x19, 144(sp)
+ sd x20, 152(sp)
+ sd x21, 160(sp)
+ sd x22, 168(sp)
+ sd x23, 176(sp)
+ sd x24, 184(sp)
+ sd x25, 192(sp)
+ sd x26, 200(sp)
+ sd x27, 208(sp)
+ sd x28, 216(sp)
+ sd x29, 224(sp)
+ sd x30, 232(sp)
+ sd x31, 240(sp)
+
+ csrr s0, CSR_SEPC
+ csrr s1, CSR_SSTATUS
+ csrr s2, CSR_SCAUSE
+ sd s0, 248(sp)
+ sd s1, 256(sp)
+ sd s2, 264(sp)
+.endm
+
+.balign 4
+.global exception_vectors
+exception_vectors:
+ save_context
+ move a0, sp
+ la ra, ret_from_exception
+ tail route_exception
+
+.global ret_from_exception
+ret_from_exception:
+ ld s2, 264(sp)
+ ld s1, 256(sp)
+ ld s0, 248(sp)
+ csrw CSR_SCAUSE, s2
+ csrw CSR_SSTATUS, s1
+ csrw CSR_SEPC, s0
+
+ ld x31, 240(sp)
+ ld x30, 232(sp)
+ ld x29, 224(sp)
+ ld x28, 216(sp)
+ ld x27, 208(sp)
+ ld x26, 200(sp)
+ ld x25, 192(sp)
+ ld x24, 184(sp)
+ ld x23, 176(sp)
+ ld x22, 168(sp)
+ ld x21, 160(sp)
+ ld x20, 152(sp)
+ ld x19, 144(sp)
+ ld x18, 136(sp)
+ ld x17, 128(sp)
+ ld x16, 120(sp)
+ ld x15, 112(sp)
+ ld x14, 104(sp)
+ ld x13, 96(sp)
+ ld x12, 88(sp)
+ ld x11, 80(sp)
+ ld x10, 72(sp)
+ ld x9, 64(sp)
+ ld x8, 56(sp)
+ ld x7, 48(sp)
+ ld x6, 40(sp)
+ ld x5, 32(sp)
+ ld x4, 24(sp)
+ ld x3, 16(sp)
+ ld x2, 8(sp)
+ ld x1, 0(sp)
+
+ addi sp, sp, (8*34)
+ sret
diff --git a/tools/testing/selftests/kvm/lib/riscv/processor.c b/tools/testing/selftests/kvm/lib/riscv/processor.c
index d146ca71e0c0..f1b0be58a5dc 100644
--- a/tools/testing/selftests/kvm/lib/riscv/processor.c
+++ b/tools/testing/selftests/kvm/lib/riscv/processor.c
@@ -13,6 +13,8 @@
#define DEFAULT_RISCV_GUEST_STACK_VADDR_MIN 0xac0000
+static vm_vaddr_t exception_handlers;
+
static uint64_t page_align(struct kvm_vm *vm, uint64_t v)
{
return (v + vm->page_size) & ~(vm->page_size - 1);
@@ -367,3 +369,58 @@ void vcpu_args_set(struct kvm_vcpu *vcpu, unsigned int num, ...)
void assert_on_unhandled_exception(struct kvm_vcpu *vcpu)
{
}
+
+struct handlers {
+ handler_fn exception_handlers[VECTOR_NUM][EC_NUM];
+};
+
+void route_exception(struct ex_regs *regs)
+{
+ struct handlers *handlers = (struct handlers *)exception_handlers;
+ int vector = 0, ec;
+
+ ec = regs->cause & ~CAUSE_IRQ_FLAG;
+ if (ec >= EC_NUM)
+ goto guest_unexpected_trap;
+
+ /* Use the same handler for all the interrupts */
+ if (regs->cause & CAUSE_IRQ_FLAG) {
+ vector = 1;
+ ec = 0;
+ }
+
+ if (handlers && handlers->exception_handlers[vector][ec])
+ return handlers->exception_handlers[vector][ec](regs);
+
+guest_unexpected_trap:
+ return guest_unexp_trap();
+}
+
+void vcpu_init_trap_vector_tables(struct kvm_vcpu *vcpu)
+{
+ extern char exception_vectors;
+
+ vcpu_set_reg(vcpu, RISCV_CSR_REG(stvec), (unsigned long)&exception_vectors);
+}
+
+void vm_init_trap_vector_tables(struct kvm_vm *vm)
+{
+ vm->handlers = __vm_vaddr_alloc(vm, sizeof(struct handlers),
+ vm->page_size, MEM_REGION_DATA);
+
+ *(vm_vaddr_t *)addr_gva2hva(vm, (vm_vaddr_t)(&exception_handlers)) = vm->handlers;
+}
+
+void vm_install_exception_handler(struct kvm_vm *vm, int ec, void (*handler)(struct ex_regs *))
+{
+ struct handlers *handlers = addr_gva2hva(vm, vm->handlers);
+
+ handlers->exception_handlers[0][ec] = handler;
+}
+
+void vm_install_interrupt_handler(struct kvm_vm *vm, void (*handler)(struct ex_regs *))
+{
+ struct handlers *handlers = addr_gva2hva(vm, vm->handlers);
+
+ handlers->exception_handlers[1][0] = handler;
+}
--
2.34.1
