Sean Christopherson <seanjc@xxxxxxxxxx> writes:
> Initialize x86's various segments in the GDT during creation of relevant
> VMs instead of waiting until vCPUs come along. Re-installing the segments
> for every vCPU is both wasteful and confusing, as is installing KERNEL_DS
> multiple times; NOT installing KERNEL_DS for GS is icing on the cake.
>
> Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
> ---
> .../selftests/kvm/lib/x86_64/processor.c | 68 ++++++-------------
> 1 file changed, 20 insertions(+), 48 deletions(-)
>
> diff --git a/tools/testing/selftests/kvm/lib/x86_64/processor.c b/tools/testing/selftests/kvm/lib/x86_64/processor.c
> index 67235013f6f9..dab719ee7734 100644
> --- a/tools/testing/selftests/kvm/lib/x86_64/processor.c
> +++ b/tools/testing/selftests/kvm/lib/x86_64/processor.c
> @@ -438,24 +438,7 @@ static void kvm_seg_fill_gdt_64bit(struct kvm_vm *vm, struct kvm_segment *segp)
> desc->base3 = segp->base >> 32;
> }
>
> -
> -/*
> - * Set Long Mode Flat Kernel Code Segment
> - *
> - * Input Args:
> - * vm - VM whose GDT is being filled, or NULL to only write segp
> - * selector - selector value
> - *
> - * Output Args:
> - * segp - Pointer to KVM segment
> - *
> - * Return: None
> - *
> - * Sets up the KVM segment pointed to by @segp, to be a code segment
> - * with the selector value given by @selector.
> - */
> -static void kvm_seg_set_kernel_code_64bit(struct kvm_vm *vm, uint16_t selector,
> - struct kvm_segment *segp)
> +static void kvm_seg_set_kernel_code_64bit(uint16_t selector, struct kvm_segment *segp)
> {
> memset(segp, 0, sizeof(*segp));
> segp->selector = selector;
> @@ -467,27 +450,9 @@ static void kvm_seg_set_kernel_code_64bit(struct kvm_vm *vm, uint16_t selector,
> segp->g = true;
> segp->l = true;
> segp->present = 1;
> - if (vm)
> - kvm_seg_fill_gdt_64bit(vm, segp);
> }
>
> -/*
> - * Set Long Mode Flat Kernel Data Segment
> - *
> - * Input Args:
> - * vm - VM whose GDT is being filled, or NULL to only write segp
> - * selector - selector value
> - *
> - * Output Args:
> - * segp - Pointer to KVM segment
> - *
> - * Return: None
> - *
> - * Sets up the KVM segment pointed to by @segp, to be a data segment
> - * with the selector value given by @selector.
> - */
> -static void kvm_seg_set_kernel_data_64bit(struct kvm_vm *vm, uint16_t selector,
> - struct kvm_segment *segp)
> +static void kvm_seg_set_kernel_data_64bit(uint16_t selector, struct kvm_segment *segp)
> {
> memset(segp, 0, sizeof(*segp));
> segp->selector = selector;
> @@ -498,8 +463,6 @@ static void kvm_seg_set_kernel_data_64bit(struct kvm_vm *vm, uint16_t selector,
> */
> segp->g = true;
> segp->present = true;
> - if (vm)
> - kvm_seg_fill_gdt_64bit(vm, segp);
> }
>
> vm_paddr_t addr_arch_gva2gpa(struct kvm_vm *vm, vm_vaddr_t gva)
> @@ -517,16 +480,15 @@ vm_paddr_t addr_arch_gva2gpa(struct kvm_vm *vm, vm_vaddr_t gva)
> return vm_untag_gpa(vm, PTE_GET_PA(*pte)) | (gva & ~HUGEPAGE_MASK(level));
> }
>
> -static void kvm_setup_tss_64bit(struct kvm_vm *vm, struct kvm_segment *segp,
> - int selector)
> +static void kvm_seg_set_tss_64bit(vm_vaddr_t base, struct kvm_segment *segp,
> + int selector)
> {
> memset(segp, 0, sizeof(*segp));
> - segp->base = vm->arch.tss;
> + segp->base = base;
> segp->limit = 0x67;
> segp->selector = selector;
> segp->type = 0xb;
> segp->present = 1;
> - kvm_seg_fill_gdt_64bit(vm, segp);
> }
>
> static void vcpu_init_sregs(struct kvm_vm *vm, struct kvm_vcpu *vcpu)
> @@ -548,11 +510,11 @@ static void vcpu_init_sregs(struct kvm_vm *vm, struct kvm_vcpu *vcpu)
> sregs.efer |= (EFER_LME | EFER_LMA | EFER_NX);
>
> kvm_seg_set_unusable(&sregs.ldt);
> - kvm_seg_set_kernel_code_64bit(vm, KERNEL_CS, &sregs.cs);
> - kvm_seg_set_kernel_data_64bit(vm, KERNEL_DS, &sregs.ds);
> - kvm_seg_set_kernel_data_64bit(vm, KERNEL_DS, &sregs.es);
> - kvm_seg_set_kernel_data_64bit(NULL, KERNEL_DS, &sregs.gs);
> - kvm_setup_tss_64bit(vm, &sregs.tr, KERNEL_TSS);
> + kvm_seg_set_kernel_code_64bit(KERNEL_CS, &sregs.cs);
> + kvm_seg_set_kernel_data_64bit(KERNEL_DS, &sregs.ds);
> + kvm_seg_set_kernel_data_64bit(KERNEL_DS, &sregs.es);
> + kvm_seg_set_kernel_data_64bit(KERNEL_DS, &sregs.gs);
> + kvm_seg_set_tss_64bit(vm->arch.tss, &sregs.tr, KERNEL_TSS);
>
> sregs.cr3 = vm->pgd;
> vcpu_sregs_set(vcpu, &sregs);
> @@ -612,6 +574,7 @@ void route_exception(struct ex_regs *regs)
> static void vm_init_descriptor_tables(struct kvm_vm *vm)
> {
> extern void *idt_handlers;
> + struct kvm_segment seg;
> int i;
>
> vm->arch.gdt = __vm_vaddr_alloc_page(vm, MEM_REGION_DATA);
> @@ -624,6 +587,15 @@ static void vm_init_descriptor_tables(struct kvm_vm *vm)
> set_idt_entry(vm, i, (unsigned long)(&idt_handlers)[i], 0, KERNEL_CS);
>
> *(vm_vaddr_t *)addr_gva2hva(vm, (vm_vaddr_t)(&exception_handlers)) = vm->handlers;
> +
> + kvm_seg_set_kernel_code_64bit(KERNEL_CS, &seg);
> + kvm_seg_fill_gdt_64bit(vm, &seg);
> +
> + kvm_seg_set_kernel_data_64bit(KERNEL_DS, &seg);
> + kvm_seg_fill_gdt_64bit(vm, &seg);
> +
> + kvm_seg_set_tss_64bit(vm->arch.tss, &seg, KERNEL_TSS);
> + kvm_seg_fill_gdt_64bit(vm, &seg);
> }
>
> void vm_install_exception_handler(struct kvm_vm *vm, int vector,
> --
> 2.44.0.291.gc1ea87d7ee-goog
Reviewed-by: Ackerley Tng <ackerleytng@xxxxxxxxxx>
