KVM: riscv: selftests: Add exception handling support

Add the infrastructure for guest exception handling in riscv selftests.
Customized handlers can be enabled by 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@intel.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Anup Patel <anup@brainfault.org>
This commit is contained in:
Haibo Xu 2024-01-22 17:58:39 +08:00 committed by Anup Patel
parent feb2c8fae3
commit 38f680c25e
4 changed files with 221 additions and 0 deletions

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@ -53,6 +53,7 @@ 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

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@ -48,6 +48,56 @@ static inline uint64_t __kvm_reg_id(uint64_t type, uint64_t subtype,
KVM_REG_RISCV_SBI_SINGLE, \
idx, KVM_REG_SIZE_ULONG)
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 NR_VECTORS 2
#define NR_EXCEPTIONS 32
#define EC_MASK (NR_EXCEPTIONS - 1)
typedef void(*exception_handler_fn)(struct ex_regs *);
void vm_init_vector_tables(struct kvm_vm *vm);
void vcpu_init_vector_tables(struct kvm_vcpu *vcpu);
void vm_install_exception_handler(struct kvm_vm *vm, int vector, exception_handler_fn handler);
void vm_install_interrupt_handler(struct kvm_vm *vm, exception_handler_fn handler);
/* L3 index Bit[47:39] */
#define PGTBL_L3_INDEX_MASK 0x0000FF8000000000ULL
#define PGTBL_L3_INDEX_SHIFT 39

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@ -0,0 +1,101 @@
/* SPDX-License-Identifier: GPL-2.0 */
/*
* Copyright (c) 2023 Intel Corporation
*/
#ifndef __ASSEMBLY__
#define __ASSEMBLY__
#endif
#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
.macro restore_context
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)
.endm
.balign 4
.global exception_vectors
exception_vectors:
save_context
move a0, sp
call route_exception
restore_context
sret

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@ -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);
@ -364,8 +366,75 @@ void vcpu_args_set(struct kvm_vcpu *vcpu, unsigned int num, ...)
va_end(ap);
}
void kvm_exit_unexpected_exception(int vector, int ec)
{
ucall(UCALL_UNHANDLED, 2, vector, ec);
}
void assert_on_unhandled_exception(struct kvm_vcpu *vcpu)
{
struct ucall uc;
if (get_ucall(vcpu, &uc) == UCALL_UNHANDLED) {
TEST_FAIL("Unexpected exception (vector:0x%lx, ec:0x%lx)",
uc.args[0], uc.args[1]);
}
}
struct handlers {
exception_handler_fn exception_handlers[NR_VECTORS][NR_EXCEPTIONS];
};
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 >= NR_EXCEPTIONS)
goto unexpected_exception;
/* 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);
unexpected_exception:
return kvm_exit_unexpected_exception(vector, ec);
}
void vcpu_init_vector_tables(struct kvm_vcpu *vcpu)
{
extern char exception_vectors;
vcpu_set_reg(vcpu, RISCV_GENERAL_CSR_REG(stvec), (unsigned long)&exception_vectors);
}
void vm_init_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 vector, exception_handler_fn handler)
{
struct handlers *handlers = addr_gva2hva(vm, vm->handlers);
assert(vector < NR_EXCEPTIONS);
handlers->exception_handlers[0][vector] = handler;
}
void vm_install_interrupt_handler(struct kvm_vm *vm, exception_handler_fn handler)
{
struct handlers *handlers = addr_gva2hva(vm, vm->handlers);
handlers->exception_handlers[1][0] = handler;
}
struct sbiret sbi_ecall(int ext, int fid, unsigned long arg0,