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_handle_exception with a (vector, error-code)
tuple. The unhandled exception reporting from the guest is done using
the new ucall UCALL_UNHANDLED.
Signed-off-by: Ricardo Koller <ricarkol@xxxxxxxxxx>
---
tools/testing/selftests/kvm/Makefile | 2 +-
.../selftests/kvm/include/aarch64/processor.h | 69 ++++++++++++
.../testing/selftests/kvm/include/kvm_util.h | 1 +
.../selftests/kvm/lib/aarch64/handlers.S | 104 ++++++++++++++++++
.../selftests/kvm/lib/aarch64/processor.c | 56 ++++++++++
5 files changed, 231 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..5c902ad95c35 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 +58,71 @@ 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 pc;
+ u64 pstate;
+ u64 sp;
+ u64 lr;
+ u64 regs[31];
+};
+
+#define VECTOR_NUM 16
+
+enum {
+ VECTOR_SYNC_EL1_SP0,
+ VECTOR_IRQ_EL1_SP0,
+ VECTOR_FIQ_EL1_SP0,
+ VECTOR_ERROR_EL1_SP0,
+
+ VECTOR_SYNC_EL1,
+ VECTOR_IRQ_EL1,
+ VECTOR_FIQ_EL1,
+ VECTOR_ERROR_EL1,
+
+ VECTOR_SYNC_EL0_64,
+ VECTOR_IRQ_EL0_64,
+ VECTOR_FIQ_EL0_64,
+ VECTOR_ERROR_EL0_64,
+
+ VECTOR_SYNC_EL0_32,
+ VECTOR_IRQ_EL0_32,
+ VECTOR_FIQ_EL0_32,
+ VECTOR_ERROR_EL0_32,
+};
+
+/* Some common EC (Exception classes) */
+#define ESR_EC_ILLEGAL_INS 0x0e
+#define ESR_EC_SVC64 0x15
+#define ESR_EC_IABORT_EL1 0x21
+#define ESR_EC_DABORT_EL1 0x25
+#define ESR_EC_SERROR 0x2f
+#define ESR_EC_HW_BP_EL1 0x31
+#define ESR_EC_SSTEP_EL1 0x33
+#define ESR_EC_WP_EL1 0x35
+#define ESR_EC_BRK_INS 0x3C
+
+#define ESR_EC_NUM 64
+
+#define ESR_EC_SHIFT 26
+#define ESR_EC_MASK 0x3f
+
+void vm_init_descriptor_tables(struct kvm_vm *vm);
+void vcpu_init_descriptor_tables(struct kvm_vm *vm, uint32_t vcpuid);
+void vm_handle_exception(struct kvm_vm *vm, int vector, int ec,
+ void (*handler)(struct ex_regs *));
+
+#define SPSR_D (1 << 9)
+#define SPSR_SS (1 << 21)
+
+#define write_sysreg(reg, val) \
+({ \
+ asm volatile("msr "__stringify(reg)", %0" : : "r"(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/include/kvm_util.h b/tools/testing/selftests/kvm/include/kvm_util.h
index bea4644d645d..7880929ea548 100644
--- a/tools/testing/selftests/kvm/include/kvm_util.h
+++ b/tools/testing/selftests/kvm/include/kvm_util.h
@@ -347,6 +347,7 @@ enum {
UCALL_SYNC,
UCALL_ABORT,
UCALL_DONE,
+ UCALL_UNHANDLED,
};
#define UCALL_MAX_ARGS 6
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..c920679b87c0
--- /dev/null
+++ b/tools/testing/selftests/kvm/lib/aarch64/handlers.S
@@ -0,0 +1,104 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+.macro save_registers, el
+ stp x28, x29, [sp, #-16]!
+ stp x26, x27, [sp, #-16]!
+ stp x24, x25, [sp, #-16]!
+ stp x22, x23, [sp, #-16]!
+ stp x20, x21, [sp, #-16]!
+ stp x18, x19, [sp, #-16]!
+ stp x16, x17, [sp, #-16]!
+ stp x14, x15, [sp, #-16]!
+ stp x12, x13, [sp, #-16]!
+ stp x10, x11, [sp, #-16]!
+ stp x8, x9, [sp, #-16]!
+ stp x6, x7, [sp, #-16]!
+ stp x4, x5, [sp, #-16]!
+ stp x2, x3, [sp, #-16]!
+ stp x0, x1, [sp, #-16]!
+
+ .if \el == 0
+ mrs x1, sp_el0
+ .else
+ mov x1, sp
+ .endif
+ stp x1, lr, [sp, #-16]! /* SP, LR */
+
+ mrs x1, elr_el1
+ mrs x2, spsr_el1
+ stp x1, x2, [sp, #-16]! /* PC, PSTATE */
+.endm
+
+.macro restore_registers, el
+ ldp x1, x2, [sp], #16 /* PC, PSTATE */
+ msr elr_el1, x1
+ msr spsr_el1, x2
+
+ ldp x1, lr, [sp], #16 /* SP, LR */
+ .if \el == 0
+ msr sp_el0, x1
+ .endif
+
+ ldp x0, x1, [sp], #16
+ ldp x2, x3, [sp], #16
+ ldp x4, x5, [sp], #16
+ ldp x6, x7, [sp], #16
+ ldp x8, x9, [sp], #16
+ ldp x10, x11, [sp], #16
+ ldp x12, x13, [sp], #16
+ ldp x14, x15, [sp], #16
+ ldp x16, x17, [sp], #16
+ ldp x18, x19, [sp], #16
+ ldp x20, x21, [sp], #16
+ ldp x22, x23, [sp], #16
+ ldp x24, x25, [sp], #16
+ ldp x26, x27, [sp], #16
+ ldp x28, x29, [sp], #16
+
+ eret
+.endm
+
+.pushsection ".entry.text", "ax"
+.balign 0x800
+.global vectors
+vectors:
+.popsection
+
+/*
+ * Build an exception handler for vector and append a jump to it into
+ * vectors (while making sure that it's 0x80 aligned).
+ */
+.macro HANDLER, el, label, vector
+handler\()\vector:
+ save_registers \el
+ mov x0, sp
+ mov x1, \vector
+ bl route_exception
+ restore_registers \el
+
+.pushsection ".entry.text", "ax"
+.balign 0x80
+ b handler\()\vector
+.popsection
+.endm
+
+.global ex_handler_code
+ex_handler_code:
+ HANDLER 1, sync, 0 // Synchronous EL1t
+ HANDLER 1, irq, 1 // IRQ EL1t
+ HANDLER 1, fiq, 2 // FIQ EL1t
+ HANDLER 1, error, 3 // Error EL1t
+
+ HANDLER 1, sync, 4 // Synchronous EL1h
+ HANDLER 1, irq, 5 // IRQ EL1h
+ HANDLER 1, fiq, 6 // FIQ EL1h
+ HANDLER 1, error, 7 // Error EL1h
+
+ HANDLER 0, sync, 8 // Synchronous 64-bit EL0
+ HANDLER 0, irq, 9 // IRQ 64-bit EL0
+ HANDLER 0, fiq, 10 // FIQ 64-bit EL0
+ HANDLER 0, error, 11 // Error 64-bit EL0
+
+ HANDLER 0, sync, 12 // Synchronous 32-bit EL0
+ HANDLER 0, irq, 13 // IRQ 32-bit EL0
+ HANDLER 0, fiq, 14 // FIQ 32-bit EL0
+ HANDLER 0, error, 15 // 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..286305b561d8 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);
@@ -336,4 +339,57 @@ void vcpu_args_set(struct kvm_vm *vm, uint32_t vcpuid, unsigned int num, ...)
void assert_on_unhandled_exception(struct kvm_vm *vm, uint32_t vcpuid)
{
+ struct ucall uc;
+
+ if (get_ucall(vm, vcpuid, &uc) == UCALL_UNHANDLED) {
+ TEST_ASSERT(false,
+ "Unexpected exception guest (vector:0x%lx, ec:0x%lx)",
+ uc.args[0], uc.args[1]);
+ }
+}
+
+void kvm_exit_unexpected_vector(int vector, uint64_t ec)
+{
+ ucall(UCALL_UNHANDLED, 2, vector, ec);
+}
+
+#define HANDLERS_IDX(_vector, _ec) ((_vector * ESR_EC_NUM) + _ec)
+
+void vm_init_descriptor_tables(struct kvm_vm *vm)
+{
+ vm->handlers = vm_vaddr_alloc(vm,
+ VECTOR_NUM * ESR_EC_NUM * sizeof(void *),
+ vm->page_size, 0, 0);
+ *(vm_vaddr_t *)addr_gva2hva(vm, (vm_vaddr_t)(&exception_handlers)) = vm->handlers;
+}
+
+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 route_exception(struct ex_regs *regs, int vector)
+{
+ typedef void(*handler)(struct ex_regs *);
+ uint64_t esr = read_sysreg(esr_el1);
+ uint64_t ec = (esr >> ESR_EC_SHIFT) & ESR_EC_MASK;
+
+ handler *handlers = (handler *)exception_handlers;
+
+ if (handlers && handlers[HANDLERS_IDX(vector, ec)])
+ handlers[HANDLERS_IDX(vector, ec)](regs);
+ else
+ kvm_exit_unexpected_vector(vector, ec);
+}
+
+void vm_handle_exception(struct kvm_vm *vm, int vector, int ec,
+ void (*handler)(struct ex_regs *))
+{
+ vm_vaddr_t *handlers = (vm_vaddr_t *)addr_gva2hva(vm, vm->handlers);
+
+ assert(vector < VECTOR_NUM);
+ assert(ec < ESR_EC_NUM);
+ handlers[HANDLERS_IDX(vector, ec)] = (vm_vaddr_t)handler;
}
--
2.31.1.498.g6c1eba8ee3d-goog
