Re: [PATCH 08/18] KVM: selftests: Move x86's descriptor table helpers "up" in processor.c

From: Ackerley Tng
Date: Wed Mar 27 2024 - 22:47:36 EST


Sean Christopherson <seanjc@xxxxxxxxxx> writes:

> Move x86's various descriptor table helpers in processor.c up above
> kvm_arch_vm_post_create() and vcpu_setup() so that the helpers can be
> made static and invoked from the aforementioned functions.
>
> No functional change intended.
>
> Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
> ---
> .../selftests/kvm/lib/x86_64/processor.c | 191 +++++++++---------
> 1 file changed, 95 insertions(+), 96 deletions(-)
>
> diff --git a/tools/testing/selftests/kvm/lib/x86_64/processor.c b/tools/testing/selftests/kvm/lib/x86_64/processor.c
> index eaeba907bb53..3640d3290f0a 100644
> --- a/tools/testing/selftests/kvm/lib/x86_64/processor.c
> +++ b/tools/testing/selftests/kvm/lib/x86_64/processor.c
> @@ -540,6 +540,21 @@ static void kvm_setup_tss_64bit(struct kvm_vm *vm, struct kvm_segment *segp,
> kvm_seg_fill_gdt_64bit(vm, segp);
> }
>
> +void vcpu_init_descriptor_tables(struct kvm_vcpu *vcpu)
> +{
> + struct kvm_vm *vm = vcpu->vm;
> + struct kvm_sregs sregs;
> +
> + vcpu_sregs_get(vcpu, &sregs);
> + sregs.idt.base = vm->arch.idt;
> + sregs.idt.limit = NUM_INTERRUPTS * sizeof(struct idt_entry) - 1;
> + sregs.gdt.base = vm->arch.gdt;
> + sregs.gdt.limit = getpagesize() - 1;
> + kvm_seg_set_kernel_data_64bit(NULL, DEFAULT_DATA_SELECTOR, &sregs.gs);
> + vcpu_sregs_set(vcpu, &sregs);
> + *(vm_vaddr_t *)addr_gva2hva(vm, (vm_vaddr_t)(&exception_handlers)) = vm->handlers;
> +}
> +
> static void vcpu_setup(struct kvm_vm *vm, struct kvm_vcpu *vcpu)
> {
> struct kvm_sregs sregs;
> @@ -572,6 +587,86 @@ static void vcpu_setup(struct kvm_vm *vm, struct kvm_vcpu *vcpu)
> vcpu_sregs_set(vcpu, &sregs);
> }
>
> +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->arch.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;
> +}
> +
> +static bool kvm_fixup_exception(struct ex_regs *regs)
> +{
> + if (regs->r9 != KVM_EXCEPTION_MAGIC || regs->rip != regs->r10)
> + return false;
> +
> + if (regs->vector == DE_VECTOR)
> + return false;
> +
> + regs->rip = regs->r11;
> + regs->r9 = regs->vector;
> + regs->r10 = regs->error_code;
> + return true;
> +}
> +
> +void route_exception(struct ex_regs *regs)
> +{
> + typedef void(*handler)(struct ex_regs *);
> + handler *handlers = (handler *)exception_handlers;
> +
> + if (handlers && handlers[regs->vector]) {
> + handlers[regs->vector](regs);
> + return;
> + }
> +
> + if (kvm_fixup_exception(regs))
> + return;
> +
> + ucall_assert(UCALL_UNHANDLED,
> + "Unhandled exception in guest", __FILE__, __LINE__,
> + "Unhandled exception '0x%lx' at guest RIP '0x%lx'",
> + regs->vector, regs->rip);
> +}
> +
> +void vm_init_descriptor_tables(struct kvm_vm *vm)
> +{
> + extern void *idt_handlers;
> + int i;
> +
> + vm->arch.idt = __vm_vaddr_alloc_page(vm, MEM_REGION_DATA);
> + vm->handlers = __vm_vaddr_alloc_page(vm, MEM_REGION_DATA);
> + /* 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 vm_install_exception_handler(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;
> +}
> +
> +void assert_on_unhandled_exception(struct kvm_vcpu *vcpu)
> +{
> + struct ucall uc;
> +
> + if (get_ucall(vcpu, &uc) == UCALL_UNHANDLED)
> + REPORT_GUEST_ASSERT(uc);
> +}
> +
> void kvm_arch_vm_post_create(struct kvm_vm *vm)
> {
> vm_create_irqchip(vm);
> @@ -1087,102 +1182,6 @@ void kvm_init_vm_address_properties(struct kvm_vm *vm)
> }
> }
>
> -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->arch.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;
> -}
> -
> -
> -static bool kvm_fixup_exception(struct ex_regs *regs)
> -{
> - if (regs->r9 != KVM_EXCEPTION_MAGIC || regs->rip != regs->r10)
> - return false;
> -
> - if (regs->vector == DE_VECTOR)
> - return false;
> -
> - regs->rip = regs->r11;
> - regs->r9 = regs->vector;
> - regs->r10 = regs->error_code;
> - return true;
> -}
> -
> -void route_exception(struct ex_regs *regs)
> -{
> - typedef void(*handler)(struct ex_regs *);
> - handler *handlers = (handler *)exception_handlers;
> -
> - if (handlers && handlers[regs->vector]) {
> - handlers[regs->vector](regs);
> - return;
> - }
> -
> - if (kvm_fixup_exception(regs))
> - return;
> -
> - ucall_assert(UCALL_UNHANDLED,
> - "Unhandled exception in guest", __FILE__, __LINE__,
> - "Unhandled exception '0x%lx' at guest RIP '0x%lx'",
> - regs->vector, regs->rip);
> -}
> -
> -void vm_init_descriptor_tables(struct kvm_vm *vm)
> -{
> - extern void *idt_handlers;
> - int i;
> -
> - vm->arch.idt = __vm_vaddr_alloc_page(vm, MEM_REGION_DATA);
> - vm->handlers = __vm_vaddr_alloc_page(vm, MEM_REGION_DATA);
> - /* 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_vcpu *vcpu)
> -{
> - struct kvm_vm *vm = vcpu->vm;
> - struct kvm_sregs sregs;
> -
> - vcpu_sregs_get(vcpu, &sregs);
> - sregs.idt.base = vm->arch.idt;
> - sregs.idt.limit = NUM_INTERRUPTS * sizeof(struct idt_entry) - 1;
> - sregs.gdt.base = vm->arch.gdt;
> - sregs.gdt.limit = getpagesize() - 1;
> - kvm_seg_set_kernel_data_64bit(NULL, DEFAULT_DATA_SELECTOR, &sregs.gs);
> - vcpu_sregs_set(vcpu, &sregs);
> - *(vm_vaddr_t *)addr_gva2hva(vm, (vm_vaddr_t)(&exception_handlers)) = vm->handlers;
> -}
> -
> -void vm_install_exception_handler(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;
> -}
> -
> -void assert_on_unhandled_exception(struct kvm_vcpu *vcpu)
> -{
> - struct ucall uc;
> -
> - if (get_ucall(vcpu, &uc) == UCALL_UNHANDLED)
> - REPORT_GUEST_ASSERT(uc);
> -}
> -
> const struct kvm_cpuid_entry2 *get_cpuid_entry(const struct kvm_cpuid2 *cpuid,
> uint32_t function, uint32_t index)
> {
> --
> 2.44.0.291.gc1ea87d7ee-goog

Reviewed-by: Ackerley Tng <ackerleytng@xxxxxxxxxx>