Add the infrastructure needed to enable exception handling in aarch64 selftests. The exception handling defaults to an unhandled-exception handler which aborts the test, just like x86. These handlers can be overridden by calling vm_install_vector_handler(vector) or vm_install_exception_handler(vector, ec). The unhandled exception reporting from the guest is done using the ucall type introduced in a previous commit, UCALL_UNHANDLED.
The exception handling code is heavily inspired on kvm-unit-tests. Signed-off-by: Ricardo Koller <[email protected]> --- tools/testing/selftests/kvm/Makefile | 2 +- .../selftests/kvm/include/aarch64/processor.h | 78 +++++++++++ .../selftests/kvm/lib/aarch64/handlers.S | 130 ++++++++++++++++++ .../selftests/kvm/lib/aarch64/processor.c | 124 +++++++++++++++++ 4 files changed, 333 insertions(+), 1 deletion(-) create mode 100644 tools/testing/selftests/kvm/lib/aarch64/handlers.S diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile index 4e548d7ab0ab..618c5903f478 100644 --- a/tools/testing/selftests/kvm/Makefile +++ b/tools/testing/selftests/kvm/Makefile @@ -35,7 +35,7 @@ endif LIBKVM = lib/assert.c lib/elf.c lib/io.c lib/kvm_util.c lib/sparsebit.c lib/test_util.c lib/guest_modes.c lib/perf_test_util.c LIBKVM_x86_64 = lib/x86_64/processor.c lib/x86_64/vmx.c lib/x86_64/svm.c lib/x86_64/ucall.c lib/x86_64/handlers.S -LIBKVM_aarch64 = lib/aarch64/processor.c lib/aarch64/ucall.c +LIBKVM_aarch64 = lib/aarch64/processor.c lib/aarch64/ucall.c lib/aarch64/handlers.S LIBKVM_s390x = lib/s390x/processor.c lib/s390x/ucall.c lib/s390x/diag318_test_handler.c TEST_GEN_PROGS_x86_64 = x86_64/cr4_cpuid_sync_test diff --git a/tools/testing/selftests/kvm/include/aarch64/processor.h b/tools/testing/selftests/kvm/include/aarch64/processor.h index b7fa0c8551db..40aae31b4afc 100644 --- a/tools/testing/selftests/kvm/include/aarch64/processor.h +++ b/tools/testing/selftests/kvm/include/aarch64/processor.h @@ -8,6 +8,7 @@ #define SELFTEST_KVM_PROCESSOR_H #include "kvm_util.h" +#include <linux/stringify.h> #define ARM64_CORE_REG(x) (KVM_REG_ARM64 | KVM_REG_SIZE_U64 | \ @@ -18,6 +19,7 @@ #define MAIR_EL1 3, 0, 10, 2, 0 #define TTBR0_EL1 3, 0, 2, 0, 0 #define SCTLR_EL1 3, 0, 1, 0, 0 +#define VBAR_EL1 3, 0, 12, 0, 0 /* * Default MAIR @@ -56,4 +58,80 @@ void aarch64_vcpu_setup(struct kvm_vm *vm, int vcpuid, struct kvm_vcpu_init *ini void aarch64_vcpu_add_default(struct kvm_vm *vm, uint32_t vcpuid, struct kvm_vcpu_init *init, void *guest_code); +struct ex_regs { + u64 regs[31]; + u64 sp; + u64 pc; + u64 pstate; +}; + +#define VECTOR_NUM 16 + +enum { + VECTOR_SYNC_CURRENT_SP0, + VECTOR_IRQ_CURRENT_SP0, + VECTOR_FIQ_CURRENT_SP0, + VECTOR_ERROR_CURRENT_SP0, + + VECTOR_SYNC_CURRENT, + VECTOR_IRQ_CURRENT, + VECTOR_FIQ_CURRENT, + VECTOR_ERROR_CURRENT, + + VECTOR_SYNC_LOWER_64, + VECTOR_IRQ_LOWER_64, + VECTOR_FIQ_LOWER_64, + VECTOR_ERROR_LOWER_64, + + VECTOR_SYNC_LOWER_32, + VECTOR_IRQ_LOWER_32, + VECTOR_FIQ_LOWER_32, + VECTOR_ERROR_LOWER_32, +}; + +#define VECTOR_IS_SYNC(v) ((v) == VECTOR_SYNC_CURRENT_SP0 || \ + (v) == VECTOR_SYNC_CURRENT || \ + (v) == VECTOR_SYNC_LOWER_64 || \ + (v) == VECTOR_SYNC_LOWER_32) + +/* Some common EC (Exception classes) */ +#define ESR_EC_ILLEGAL_INS 0x0e +#define ESR_EC_SVC64 0x15 +#define ESR_EC_IABORT_CURRENT 0x21 +#define ESR_EC_DABORT_CURRENT 0x25 +#define ESR_EC_SERROR 0x2f +#define ESR_EC_HW_BP_CURRENT 0x31 +#define ESR_EC_SSTEP_CURRENT 0x33 +#define ESR_EC_WP_CURRENT 0x35 +#define ESR_EC_BRK_INS 0x3C + +#define ESR_EC_NUM 64 + +#define ESR_EC_SHIFT 26 +#define ESR_EC_MASK (ESR_EC_NUM - 1) + +void vm_init_descriptor_tables(struct kvm_vm *vm); +void vcpu_init_descriptor_tables(struct kvm_vm *vm, uint32_t vcpuid); + +typedef void(*handler_fn)(struct ex_regs *); +void vm_install_exception_handler(struct kvm_vm *vm, + int vector, int ec, handler_fn handler); +void vm_install_vector_handler(struct kvm_vm *vm, + int vector, handler_fn handler); + +#define SPSR_D (1 << 9) +#define SPSR_SS (1 << 21) + +#define write_sysreg(reg, val) \ +({ \ + u64 __val = (u64)(val); \ + asm volatile("msr " __stringify(reg) ", %x0" : : "rZ" (__val)); \ +}) + +#define read_sysreg(reg) \ +({ u64 val; \ + asm volatile("mrs %0, "__stringify(reg) : "=r"(val) : : "memory");\ + val; \ +}) + #endif /* SELFTEST_KVM_PROCESSOR_H */ diff --git a/tools/testing/selftests/kvm/lib/aarch64/handlers.S b/tools/testing/selftests/kvm/lib/aarch64/handlers.S new file mode 100644 index 000000000000..8a560021892b --- /dev/null +++ b/tools/testing/selftests/kvm/lib/aarch64/handlers.S @@ -0,0 +1,130 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +.macro save_registers, vector + add sp, sp, #-16 * 17 + + stp x0, x1, [sp, #16 * 0] + stp x2, x3, [sp, #16 * 1] + stp x4, x5, [sp, #16 * 2] + stp x6, x7, [sp, #16 * 3] + stp x8, x9, [sp, #16 * 4] + stp x10, x11, [sp, #16 * 5] + stp x12, x13, [sp, #16 * 6] + stp x14, x15, [sp, #16 * 7] + stp x16, x17, [sp, #16 * 8] + stp x18, x19, [sp, #16 * 9] + stp x20, x21, [sp, #16 * 10] + stp x22, x23, [sp, #16 * 11] + stp x24, x25, [sp, #16 * 12] + stp x26, x27, [sp, #16 * 13] + stp x28, x29, [sp, #16 * 14] + + .if \vector >= 8 + mrs x1, sp_el0 + .else + /* + * This stores sp_el1 into ex_regs.sp so exception handlers can + * "look" at it. It will _not_ be used to restore the sp_el1 on + * return from the exception so handlers can not update it. + */ + mov x1, sp + .endif + stp x30, x1, [sp, #16 * 15] /* x30, SP */ + + mrs x1, elr_el1 + mrs x2, spsr_el1 + stp x1, x2, [sp, #16 * 16] /* PC, PSTATE */ +.endm + +.macro restore_registers, vector + ldp x1, x2, [sp, #16 * 16] /* PC, PSTATE */ + msr elr_el1, x1 + msr spsr_el1, x2 + + ldp x30, x1, [sp, #16 * 15] /* x30, SP */ + .if \vector >= 8 + msr sp_el0, x1 + .endif + + ldp x28, x29, [sp, #16 * 14] + ldp x26, x27, [sp, #16 * 13] + ldp x24, x25, [sp, #16 * 12] + ldp x22, x23, [sp, #16 * 11] + ldp x20, x21, [sp, #16 * 10] + ldp x18, x19, [sp, #16 * 9] + ldp x16, x17, [sp, #16 * 8] + ldp x14, x15, [sp, #16 * 7] + ldp x12, x13, [sp, #16 * 6] + ldp x10, x11, [sp, #16 * 5] + ldp x8, x9, [sp, #16 * 4] + ldp x6, x7, [sp, #16 * 3] + ldp x4, x5, [sp, #16 * 2] + ldp x2, x3, [sp, #16 * 1] + ldp x0, x1, [sp, #16 * 0] + + add sp, sp, #16 * 17 + + eret +.endm + +.pushsection ".entry.text", "ax" +.balign 0x800 +.global vectors +vectors: +.popsection + +.set vector, 0 + +/* + * Build an exception handler for vector and append a jump to it into + * vectors (while making sure that it's 0x80 aligned). + */ +.macro HANDLER, label +handler_\()\label: + save_registers vector + mov x0, sp + mov x1, #vector + bl route_exception + restore_registers vector + +.pushsection ".entry.text", "ax" +.balign 0x80 + b handler_\()\label +.popsection + +.set vector, vector + 1 +.endm + +.macro HANDLER_INVALID +.pushsection ".entry.text", "ax" +.balign 0x80 +/* This will abort so no need to save and restore registers. */ + mov x0, #vector + b kvm_exit_unexpected_vector +.popsection + +.set vector, vector + 1 +.endm + +/* + * Caution: be sure to not add anything between the declaration of vectors + * above and these macro calls that will build the vectors table below it. + */ + HANDLER_INVALID // Synchronous EL1t + HANDLER_INVALID // IRQ EL1t + HANDLER_INVALID // FIQ EL1t + HANDLER_INVALID // Error EL1t + + HANDLER el1h_sync // Synchronous EL1h + HANDLER el1h_irq // IRQ EL1h + HANDLER el1h_fiq // FIQ EL1h + HANDLER el1h_error // Error EL1h + + HANDLER el0_sync_64 // Synchronous 64-bit EL0 + HANDLER el0_irq_64 // IRQ 64-bit EL0 + HANDLER el0_fiq_64 // FIQ 64-bit EL0 + HANDLER el0_error_64 // Error 64-bit EL0 + + HANDLER el0_sync_32 // Synchronous 32-bit EL0 + HANDLER el0_irq_32 // IRQ 32-bit EL0 + HANDLER el0_fiq_32 // FIQ 32-bit EL0 + HANDLER el0_error_32 // Error 32-bit EL0 diff --git a/tools/testing/selftests/kvm/lib/aarch64/processor.c b/tools/testing/selftests/kvm/lib/aarch64/processor.c index cee92d477dc0..25be71ec88be 100644 --- a/tools/testing/selftests/kvm/lib/aarch64/processor.c +++ b/tools/testing/selftests/kvm/lib/aarch64/processor.c @@ -6,6 +6,7 @@ */ #include <linux/compiler.h> +#include <assert.h> #include "kvm_util.h" #include "../kvm_util_internal.h" @@ -14,6 +15,8 @@ #define KVM_GUEST_PAGE_TABLE_MIN_PADDR 0x180000 #define DEFAULT_ARM64_GUEST_STACK_VADDR_MIN 0xac0000 +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); @@ -334,6 +337,127 @@ void vcpu_args_set(struct kvm_vm *vm, uint32_t vcpuid, unsigned int num, ...) va_end(ap); } +void kvm_exit_unexpected_vector(int vector) +{ + ucall(UCALL_UNHANDLED, 3, vector, 0, false /* !valid_ec */); +} + +void kvm_exit_unexpected_exception(int vector, uint64_t ec) +{ + ucall(UCALL_UNHANDLED, 3, vector, ec, true /* valid_ec */); +} + void assert_on_unhandled_exception(struct kvm_vm *vm, uint32_t vcpuid) { + struct ucall uc; + + if (get_ucall(vm, vcpuid, &uc) != UCALL_UNHANDLED) + return; + + if (uc.args[2]) /* valid_ec */ { + assert(VECTOR_IS_SYNC(uc.args[0])); + TEST_ASSERT(false, + "Unexpected exception (vector:0x%lx, ec:0x%lx)", + uc.args[0], uc.args[1]); + } else { + assert(!VECTOR_IS_SYNC(uc.args[0])); + TEST_ASSERT(false, + "Unexpected exception (vector:0x%lx)", + uc.args[0]); + } +} + +/* + * This exception handling code was heavily inspired on kvm-unit-tests. There + * is a set of default vector handlers stored in vector_handlers. These default + * vector handlers call user-installed handlers stored in exception_handlers. + * Synchronous handlers are indexed by (vector, ec), and irq handlers by + * (vector, ec=0). + */ + +typedef void(*vector_fn)(struct ex_regs *, int vector); + +struct handlers { + vector_fn vector_handlers[VECTOR_NUM]; + handler_fn exception_handlers[VECTOR_NUM][ESR_EC_NUM]; +}; + +void vcpu_init_descriptor_tables(struct kvm_vm *vm, uint32_t vcpuid) +{ + extern char vectors; + + set_reg(vm, vcpuid, ARM64_SYS_REG(VBAR_EL1), (uint64_t)&vectors); +} + +void default_sync_handler(struct ex_regs *regs, int vector) +{ + struct handlers *handlers = (struct handlers *)exception_handlers; + uint64_t esr = read_sysreg(esr_el1); + uint64_t ec = (esr >> ESR_EC_SHIFT) & ESR_EC_MASK; + + GUEST_ASSERT(VECTOR_IS_SYNC(vector)); + + if (handlers && handlers->exception_handlers[vector][ec]) + handlers->exception_handlers[vector][ec](regs); + else + kvm_exit_unexpected_exception(vector, ec); +} + +void default_irq_handler(struct ex_regs *regs, int vector) +{ + struct handlers *handlers = (struct handlers *)exception_handlers; + + GUEST_ASSERT(!VECTOR_IS_SYNC(vector)); + + if (handlers && handlers->exception_handlers[vector][0]) + handlers->exception_handlers[vector][0](regs); + else + kvm_exit_unexpected_vector(vector); +} + +void route_exception(struct ex_regs *regs, int vector) +{ + struct handlers *handlers = (struct handlers *)exception_handlers; + + if (handlers && handlers->vector_handlers[vector]) + handlers->vector_handlers[vector](regs, vector); + else + kvm_exit_unexpected_vector(vector); +} + +void vm_init_descriptor_tables(struct kvm_vm *vm) +{ + struct handlers *handlers; + + vm->handlers = vm_vaddr_alloc(vm, sizeof(struct handlers), + vm->page_size, 0, 0); + + handlers = (struct handlers *)addr_gva2hva(vm, vm->handlers); + handlers->vector_handlers[VECTOR_SYNC_CURRENT] = default_sync_handler; + handlers->vector_handlers[VECTOR_IRQ_CURRENT] = default_irq_handler; + handlers->vector_handlers[VECTOR_SYNC_LOWER_64] = default_sync_handler; + handlers->vector_handlers[VECTOR_IRQ_LOWER_64] = default_irq_handler; + + *(vm_vaddr_t *)addr_gva2hva(vm, (vm_vaddr_t)(&exception_handlers)) = vm->handlers; +} + +void vm_install_exception_handler(struct kvm_vm *vm, int vector, int ec, + void (*handler)(struct ex_regs *)) +{ + struct handlers *handlers = (struct handlers *)addr_gva2hva(vm, vm->handlers); + + assert(VECTOR_IS_SYNC(vector)); + assert(vector < VECTOR_NUM); + assert(ec < ESR_EC_NUM); + handlers->exception_handlers[vector][ec] = handler; +} + +void vm_install_vector_handler(struct kvm_vm *vm, int vector, + void (*handler)(struct ex_regs *)) +{ + struct handlers *handlers = (struct handlers *)addr_gva2hva(vm, vm->handlers); + + assert(!VECTOR_IS_SYNC(vector)); + assert(vector < VECTOR_NUM); + handlers->exception_handlers[vector][0] = handler; } -- 2.31.1.527.g47e6f16901-goog _______________________________________________ kvmarm mailing list [email protected] https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
