Commit 0f53a024 authored by Sean Christopherson's avatar Sean Christopherson
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KVM: selftests: Init x86's segments during VM creation 



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.

Reviewed-by: default avatarAckerley Tng <ackerleytng@google.com>
Link: https://lore.kernel.org/r/20240314232637.2538648-18-seanjc@google.com


Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
parent f18ef97f

tools/testing/selftests/kvm/lib/x86_64/processor.c

+20 −48
Original line number Diff line number Diff line
@@ -439,24 +439,7 @@ 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;
@@ -468,27 +451,9 @@ 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;
@@ -499,8 +464,6 @@ 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)
@@ -518,16 +481,15 @@ 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,

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)
@@ -549,11 +511,11 @@ 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);
@@ -613,6 +575,7 @@ 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);
@@ -625,6 +588,15 @@ 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,