On 06.10.20 23:04, Aaron Lewis wrote:
Add the infrastructure needed to enable exception handling in selftests.
This allows any of the exception and interrupt vectors to be overridden
in the guest.
Signed-off-by: Aaron Lewis <aaronlewis@xxxxxxxxxx>
---
tools/testing/selftests/kvm/Makefile | 19 ++--
.../selftests/kvm/include/x86_64/processor.h | 24 +++++
tools/testing/selftests/kvm/lib/kvm_util.c | 15 +++
.../selftests/kvm/lib/kvm_util_internal.h | 2 +
.../selftests/kvm/lib/x86_64/handlers.S | 81 ++++++++++++++
.../selftests/kvm/lib/x86_64/processor.c | 100 +++++++++++++++++-
6 files changed, 232 insertions(+), 9 deletions(-)
create mode 100644 tools/testing/selftests/kvm/lib/x86_64/handlers.S
diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
index 7ebe71fbca53..aaaf992faf87 100644
--- a/tools/testing/selftests/kvm/Makefile
+++ b/tools/testing/selftests/kvm/Makefile
@@ -34,7 +34,7 @@ ifeq ($(ARCH),s390)
endif
LIBKVM = lib/assert.c lib/elf.c lib/io.c lib/kvm_util.c lib/sparsebit.c lib/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
+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_s390x = lib/s390x/processor.c lib/s390x/ucall.c
@@ -110,14 +110,21 @@ LDFLAGS += -pthread $(no-pie-option) $(pgste-option)
include ../lib.mk
STATIC_LIBS := $(OUTPUT)/libkvm.a
-LIBKVM_OBJ := $(patsubst %.c, $(OUTPUT)/%.o, $(LIBKVM))
-EXTRA_CLEAN += $(LIBKVM_OBJ) $(STATIC_LIBS) cscope.*
+LIBKVM_C := $(filter %.c,$(LIBKVM))
+LIBKVM_S := $(filter %.S,$(LIBKVM))
+LIBKVM_C_OBJ := $(patsubst %.c, $(OUTPUT)/%.o, $(LIBKVM_C))
+LIBKVM_S_OBJ := $(patsubst %.S, $(OUTPUT)/%.o, $(LIBKVM_S))
+EXTRA_CLEAN += $(LIBKVM_C_OBJ) $(LIBKVM_S_OBJ) $(STATIC_LIBS) cscope.*
+
+x := $(shell mkdir -p $(sort $(dir $(LIBKVM_C_OBJ) $(LIBKVM_S_OBJ))))
+$(LIBKVM_C_OBJ): $(OUTPUT)/%.o: %.c
+ $(CC) $(CFLAGS) $(CPPFLAGS) $(TARGET_ARCH) -c $< -o $@
-x := $(shell mkdir -p $(sort $(dir $(LIBKVM_OBJ))))
-$(LIBKVM_OBJ): $(OUTPUT)/%.o: %.c
+$(LIBKVM_S_OBJ): $(OUTPUT)/%.o: %.S
$(CC) $(CFLAGS) $(CPPFLAGS) $(TARGET_ARCH) -c $< -o $@
-$(OUTPUT)/libkvm.a: $(LIBKVM_OBJ)
+LIBKVM_OBJS = $(LIBKVM_C_OBJ) $(LIBKVM_S_OBJ)
+$(OUTPUT)/libkvm.a: $(LIBKVM_OBJS)
$(AR) crs $@ $^
x := $(shell mkdir -p $(sort $(dir $(TEST_GEN_PROGS))))
diff --git a/tools/testing/selftests/kvm/include/x86_64/processor.h b/tools/testing/selftests/kvm/include/x86_64/processor.h
index 0a65e7bb5249..02530dc6339b 100644
--- a/tools/testing/selftests/kvm/include/x86_64/processor.h
+++ b/tools/testing/selftests/kvm/include/x86_64/processor.h
@@ -36,6 +36,8 @@
#define X86_CR4_SMAP (1ul << 21)
#define X86_CR4_PKE (1ul << 22)
+#define UNEXPECTED_VECTOR_PORT 0xfff0u
+
/* General Registers in 64-Bit Mode */
struct gpr64_regs {
u64 rax;
@@ -239,6 +241,11 @@ static inline struct desc_ptr get_idt(void)
return idt;
}
+static inline void outl(uint16_t port, uint32_t value)
+{
+ __asm__ __volatile__("outl %%eax, %%dx" : : "d"(port), "a"(value));
+}
+
#define SET_XMM(__var, __xmm) \
asm volatile("movq %0, %%"#__xmm : : "r"(__var) : #__xmm)
@@ -338,6 +345,23 @@ uint32_t kvm_get_cpuid_max_basic(void);
uint32_t kvm_get_cpuid_max_extended(void);
void kvm_get_cpu_address_width(unsigned int *pa_bits, unsigned int *va_bits);
+struct ex_regs {
+ uint64_t rax, rcx, rdx, rbx;
+ uint64_t rbp, rsi, rdi;
+ uint64_t r8, r9, r10, r11;
+ uint64_t r12, r13, r14, r15;
+ uint64_t vector;
+ uint64_t error_code;
+ uint64_t rip;
+ uint64_t cs;
+ uint64_t rflags;
+};
+
+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,
+ void (*handler)(struct ex_regs *));
+
/*
* Basic CPU control in CR0
*/
diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
index 74776ee228f2..9eed3fc21c39 100644
--- a/tools/testing/selftests/kvm/lib/kvm_util.c
+++ b/tools/testing/selftests/kvm/lib/kvm_util.c
@@ -1195,6 +1195,21 @@ int _vcpu_run(struct kvm_vm *vm, uint32_t vcpuid)
do {
rc = ioctl(vcpu->fd, KVM_RUN, NULL);
} while (rc == -1 && errno == EINTR);
+
+#ifdef __x86_64__
Could this be an arch callback?
+ if (vcpu_state(vm, vcpuid)->exit_reason == KVM_EXIT_IO
+ && vcpu_state(vm, vcpuid)->io.port == UNEXPECTED_VECTOR_PORT
+ && vcpu_state(vm, vcpuid)->io.size == 4) {
+ /* Grab pointer to io data */
+ uint32_t *data = (void *)vcpu_state(vm, vcpuid)
+ + vcpu_state(vm, vcpuid)->io.data_offset;
+
+ TEST_ASSERT(false,
+ "Unexpected vectored event in guest (vector:0x%x)",
+ *data);
+ }
+#endif
+
return rc;
}
diff --git a/tools/testing/selftests/kvm/lib/kvm_util_internal.h b/tools/testing/selftests/kvm/lib/kvm_util_internal.h
index 2ef446520748..f07d383d03a1 100644
--- a/tools/testing/selftests/kvm/lib/kvm_util_internal.h
+++ b/tools/testing/selftests/kvm/lib/kvm_util_internal.h
@@ -50,6 +50,8 @@ struct kvm_vm {
vm_paddr_t pgd;
vm_vaddr_t gdt;
vm_vaddr_t tss;
+ vm_vaddr_t idt;
+ vm_vaddr_t handlers;
};
struct vcpu *vcpu_find(struct kvm_vm *vm, uint32_t vcpuid);
diff --git a/tools/testing/selftests/kvm/lib/x86_64/handlers.S b/tools/testing/selftests/kvm/lib/x86_64/handlers.S
new file mode 100644
index 000000000000..aaf7bc7d2ce1
--- /dev/null
+++ b/tools/testing/selftests/kvm/lib/x86_64/handlers.S
@@ -0,0 +1,81 @@
+handle_exception:
+ push %r15
+ push %r14
+ push %r13
+ push %r12
+ push %r11
+ push %r10
+ push %r9
+ push %r8
+
+ push %rdi
+ push %rsi
+ push %rbp
+ push %rbx
+ push %rdx
+ push %rcx
+ push %rax
+ mov %rsp, %rdi
+
+ call route_exception
+
+ pop %rax
+ pop %rcx
+ pop %rdx
+ pop %rbx
+ pop %rbp
+ pop %rsi
+ pop %rdi
+ pop %r8
+ pop %r9
+ pop %r10
+ pop %r11
+ pop %r12
+ pop %r13
+ pop %r14
+ pop %r15
+
+ /* Discard vector and error code. */
+ add $16, %rsp
+ iretq
+
+/*
+ * Build the handle_exception wrappers which push the vector/error code on the
+ * stack and an array of pointers to those wrappers.
+ */
+.pushsection .rodata
+.globl idt_handlers
+idt_handlers:
+.popsection
+
+.macro HANDLERS has_error from to
+ vector = \from
+ .rept \to - \from + 1
+ .align 8
+
+ /* Fetch current address and append it to idt_handlers. */
+ current_handler = .
+.pushsection .rodata
+.quad current_handler
+.popsection
+
+ .if ! \has_error
+ pushq $0
+ .endif
+ pushq $vector
+ jmp handle_exception
+ vector = vector + 1
+ .endr
+.endm
+
+.global idt_handler_code
+idt_handler_code:
+ HANDLERS has_error=0 from=0 to=7
+ HANDLERS has_error=1 from=8 to=8
+ HANDLERS has_error=0 from=9 to=9
+ HANDLERS has_error=1 from=10 to=14
+ HANDLERS has_error=0 from=15 to=16
+ HANDLERS has_error=1 from=17 to=17
+ HANDLERS has_error=0 from=18 to=255
+
+.section .note.GNU-stack, "", %progbits
diff --git a/tools/testing/selftests/kvm/lib/x86_64/processor.c b/tools/testing/selftests/kvm/lib/x86_64/processor.c
index 1ccf6c9b3476..c15817b36267 100644
--- a/tools/testing/selftests/kvm/lib/x86_64/processor.c
+++ b/tools/testing/selftests/kvm/lib/x86_64/processor.c
@@ -12,6 +12,13 @@
#include "../kvm_util_internal.h"
#include "processor.h"
+#ifndef NUM_INTERRUPTS
+#define NUM_INTERRUPTS 256
+#endif
+
+#define DEFAULT_CODE_SELECTOR 0x8
+#define DEFAULT_DATA_SELECTOR 0x10
+
/* Minimum physical address used for virtual translation tables. */
#define KVM_GUEST_PAGE_TABLE_MIN_PADDR 0x180000
@@ -557,9 +564,9 @@ static void vcpu_setup(struct kvm_vm *vm, int vcpuid, int pgd_memslot, int gdt_m
sregs.efer |= (EFER_LME | EFER_LMA | EFER_NX);
kvm_seg_set_unusable(&sregs.ldt);
- kvm_seg_set_kernel_code_64bit(vm, 0x8, &sregs.cs);
- kvm_seg_set_kernel_data_64bit(vm, 0x10, &sregs.ds);
- kvm_seg_set_kernel_data_64bit(vm, 0x10, &sregs.es);
+ kvm_seg_set_kernel_code_64bit(vm, DEFAULT_CODE_SELECTOR, &sregs.cs);
+ kvm_seg_set_kernel_data_64bit(vm, DEFAULT_DATA_SELECTOR, &sregs.ds);
+ kvm_seg_set_kernel_data_64bit(vm, DEFAULT_DATA_SELECTOR, &sregs.es);
kvm_setup_tss_64bit(vm, &sregs.tr, 0x18, gdt_memslot, pgd_memslot);
break;
@@ -1119,3 +1126,90 @@ void kvm_get_cpu_address_width(unsigned int *pa_bits, unsigned int *va_bits)
*va_bits = (entry->eax >> 8) & 0xff;
}
}
+
+struct idt_entry {
+ uint16_t offset0;
+ uint16_t selector;
+ uint16_t ist : 3;
+ uint16_t : 5;
+ uint16_t type : 4;
+ uint16_t : 1;
+ uint16_t dpl : 2;
+ uint16_t p : 1;
+ uint16_t offset1;
+ uint32_t offset2; uint32_t reserved;
+};
+
+static void set_idt_entry(struct kvm_vm *vm, int vector, unsigned long addr,
+ int dpl, unsigned short selector)
+{
+ struct idt_entry *base =
+ (struct idt_entry *)addr_gva2hva(vm, vm->idt);
+ struct idt_entry *e = &base[vector];
+
+ memset(e, 0, sizeof(*e));
+ e->offset0 = addr;
+ e->selector = selector;
+ e->ist = 0;
+ e->type = 14;
+ e->dpl = dpl;
+ e->p = 1;
+ e->offset1 = addr >> 16;
+ e->offset2 = addr >> 32;
+}
+
+void kvm_exit_unexpected_vector(uint32_t value)
+{
+ outl(UNEXPECTED_VECTOR_PORT, value);
+}
+
+void route_exception(struct ex_regs *regs)
+{
+ typedef void(*handler)(struct ex_regs *);
+ handler *handlers;
+
+ handlers = (handler *)rdmsr(MSR_GS_BASE);
Why can't this just be a global? Using GS to transmit the pointer might
collide with test cases that modify GS, no?
Alex
+
+ if (handlers[regs->vector]) {
+ handlers[regs->vector](regs);
+ return;
+ }
+
+ kvm_exit_unexpected_vector(regs->vector);
+}
+
+void vm_init_descriptor_tables(struct kvm_vm *vm)
+{
+ extern void *idt_handlers;
+ int i;
+
+ vm->idt = vm_vaddr_alloc(vm, getpagesize(), 0x2000, 0, 0);
+ vm->handlers = vm_vaddr_alloc(vm, 256 * sizeof(void *), 0x2000, 0, 0);
+ /* Handlers have the same address in both address spaces.*/
+ for (i = 0; i < NUM_INTERRUPTS; i++)
+ set_idt_entry(vm, i, (unsigned long)(&idt_handlers)[i], 0,
+ DEFAULT_CODE_SELECTOR);
+}
+
+void vcpu_init_descriptor_tables(struct kvm_vm *vm, uint32_t vcpuid)
+{
+ struct kvm_sregs sregs;
+
+ vcpu_sregs_get(vm, vcpuid, &sregs);
+ sregs.idt.base = vm->idt;
+ sregs.idt.limit = NUM_INTERRUPTS * sizeof(struct idt_entry) - 1;
+ sregs.gdt.base = vm->gdt;
+ sregs.gdt.limit = getpagesize() - 1;
+ /* Use GS Base to pass the pointer to the handlers to the guest.*/
+ kvm_seg_set_kernel_data_64bit(NULL, DEFAULT_DATA_SELECTOR, &sregs.gs);
+ sregs.gs.base = (unsigned long) vm->handlers;
+ vcpu_sregs_set(vm, vcpuid, &sregs);
+}
+
+void vm_handle_exception(struct kvm_vm *vm, int vector,
+ void (*handler)(struct ex_regs *))
+{
+ vm_vaddr_t *handlers = (vm_vaddr_t *)addr_gva2hva(vm, vm->handlers);
+
+ handlers[vector] = (vm_vaddr_t)handler;
+}
--
2.28.0.806.g8561365e88-goog
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