On Mon, Aug 11, 2025 at 1:11 PM Sean Christopherson seanjc@google.com wrote:
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);
Thanks for the suggestion. I'll be dropping this patch in the next version.
+}
+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