On Thu, Aug 07, 2025, Sagi Shahar wrote:
From: Ackerley Tng ackerleytng@google.com
Make changelogs standalone, i.e. don't rely on the subject/shortlog for context.
This allows initializing sregs without setting vCPU registers in KVM.
No functional change intended.
Signed-off-by: Ackerley Tng ackerleytng@google.com Signed-off-by: Sagi Shahar sagis@google.com
.../selftests/kvm/include/x86/processor.h | 1 + .../testing/selftests/kvm/lib/x86/processor.c | 45 ++++++++++--------- 2 files changed, 25 insertions(+), 21 deletions(-)
diff --git a/tools/testing/selftests/kvm/include/x86/processor.h b/tools/testing/selftests/kvm/include/x86/processor.h index b11b5a53ebd5..f2eb764cbd7c 100644 --- a/tools/testing/selftests/kvm/include/x86/processor.h +++ b/tools/testing/selftests/kvm/include/x86/processor.h @@ -1025,6 +1025,7 @@ static inline struct kvm_cpuid2 *allocate_kvm_cpuid2(int nr_entries) } void vcpu_init_cpuid(struct kvm_vcpu *vcpu, const struct kvm_cpuid2 *cpuid); +void vcpu_setup_mode_sregs(struct kvm_vm *vm, struct kvm_sregs *sregs); static inline void vcpu_get_cpuid(struct kvm_vcpu *vcpu) { diff --git a/tools/testing/selftests/kvm/lib/x86/processor.c b/tools/testing/selftests/kvm/lib/x86/processor.c index a92dc1dad085..002303e2a572 100644 --- a/tools/testing/selftests/kvm/lib/x86/processor.c +++ b/tools/testing/selftests/kvm/lib/x86/processor.c @@ -488,34 +488,37 @@ static void kvm_seg_set_tss_64bit(vm_vaddr_t base, struct kvm_segment *segp) segp->present = 1; } -static void vcpu_init_sregs(struct kvm_vm *vm, struct kvm_vcpu *vcpu) +void vcpu_setup_mode_sregs(struct kvm_vm *vm, struct kvm_sregs *sregs) {
- struct kvm_sregs sregs;
- TEST_ASSERT_EQ(vm->mode, VM_MODE_PXXV48_4K);
- /* Set mode specific system register values. */
- 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;
- 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;
- sregs.cr0 = X86_CR0_PE | X86_CR0_NE | X86_CR0_PG;
- sregs.cr4 |= X86_CR4_PAE | X86_CR4_OSFXSR;
- sregs->cr0 = X86_CR0_PE | X86_CR0_NE | X86_CR0_PG;
- sregs->cr4 |= X86_CR4_PAE | X86_CR4_OSFXSR; if (kvm_cpu_has(X86_FEATURE_XSAVE))
sregs.cr4 |= X86_CR4_OSXSAVE;- sregs.efer |= (EFER_LME | EFER_LMA | EFER_NX);
sregs->cr4 |= X86_CR4_OSXSAVE;- sregs->efer |= (EFER_LME | EFER_LMA | EFER_NX);
- kvm_seg_set_unusable(&sregs->ldt);
- kvm_seg_set_kernel_code_64bit(&sregs->cs);
- kvm_seg_set_kernel_data_64bit(&sregs->ds);
- kvm_seg_set_kernel_data_64bit(&sregs->es);
- kvm_seg_set_kernel_data_64bit(&sregs->gs);
- kvm_seg_set_tss_64bit(vm->arch.tss, &sregs->tr);
- kvm_seg_set_unusable(&sregs.ldt);
- kvm_seg_set_kernel_code_64bit(&sregs.cs);
- kvm_seg_set_kernel_data_64bit(&sregs.ds);
- kvm_seg_set_kernel_data_64bit(&sregs.es);
- kvm_seg_set_kernel_data_64bit(&sregs.gs);
- kvm_seg_set_tss_64bit(vm->arch.tss, &sregs.tr);
- sregs->cr3 = vm->pgd;
Add helpers/macros for the few things that are open coded here so that the TDX code can get the "default" values. Bouncing data through kvm_sregs is unnecessary (unless you're trying to win the Obfuscated C contest) and makes it much harder to understand what TDX actually needs, and why.
IDT.base, GDT.base, and CR3 (vm->pgd) are already available, so something like:
diff --git a/tools/testing/selftests/kvm/lib/x86/processor.c b/tools/testing/selftests/kvm/lib/x86/processor.c index d4c19ac885a9..83efcf48faad 100644 --- a/tools/testing/selftests/kvm/lib/x86/processor.c +++ b/tools/testing/selftests/kvm/lib/x86/processor.c @@ -498,15 +498,13 @@ static void vcpu_init_sregs(struct kvm_vm *vm, struct kvm_vcpu *vcpu) vcpu_sregs_get(vcpu, &sregs);
sregs.idt.base = vm->arch.idt; - sregs.idt.limit = NUM_INTERRUPTS * sizeof(struct idt_entry) - 1; + sregs.idt.limit = kvm_get_default_idt_limit(); sregs.gdt.base = vm->arch.gdt; - sregs.gdt.limit = getpagesize() - 1; + sregs.gdt.limit = kvm_get_default_gdt_limit();
- sregs.cr0 = X86_CR0_PE | X86_CR0_NE | X86_CR0_PG; - sregs.cr4 |= X86_CR4_PAE | X86_CR4_OSFXSR; - if (kvm_cpu_has(X86_FEATURE_XSAVE)) - sregs.cr4 |= X86_CR4_OSXSAVE; - sregs.efer |= (EFER_LME | EFER_LMA | EFER_NX); + sregs.cr0 = kvm_get_default_cr0(); + sregs.cr4 |= kvm_get_default_cr4(); + sregs.efer |= kvm_get_default_efer();
kvm_seg_set_unusable(&sregs.ldt); kvm_seg_set_kernel_code_64bit(&sregs.cs);
+}
+static void vcpu_init_sregs(struct kvm_vm *vm, struct kvm_vcpu *vcpu) +{
- struct kvm_sregs sregs;
- sregs.cr3 = vm->pgd;
- vcpu_sregs_get(vcpu, &sregs);
- vcpu_setup_mode_sregs(vm, &sregs); vcpu_sregs_set(vcpu, &sregs);
} -- 2.51.0.rc0.155.g4a0f42376b-goog