linux-kernel - [PATCH v6 02/30] KVM: selftests: Expose function that sets up sregs based on VM's mode

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Message-ID: <20250414214801.2693294-3-sagis@google.com>
Date: Mon, 14 Apr 2025 14:47:31 -0700
From: Sagi Shahar <sagis@...gle.com>
To: linux-kselftest@...r.kernel.org, Paolo Bonzini <pbonzini@...hat.com>, 
	Shuah Khan <shuah@...nel.org>, Sean Christopherson <seanjc@...gle.com>, 
	Ackerley Tng <ackerleytng@...gle.com>, Ryan Afranji <afranji@...gle.com>, 
	Andrew Jones <ajones@...tanamicro.com>, Isaku Yamahata <isaku.yamahata@...el.com>, 
	Erdem Aktas <erdemaktas@...gle.com>, Rick Edgecombe <rick.p.edgecombe@...el.com>, 
	Sagi Shahar <sagis@...gle.com>, Roger Wang <runanwang@...gle.com>, 
	Binbin Wu <binbin.wu@...ux.intel.com>, Oliver Upton <oliver.upton@...ux.dev>, 
	"Pratik R. Sampat" <pratikrajesh.sampat@....com>, Reinette Chatre <reinette.chatre@...el.com>
Cc: linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Subject: [PATCH v6 02/30] KVM: selftests: Expose function that sets up sregs
 based on VM's mode

From: Ackerley Tng <ackerleytng@...gle.com>

This allows initializing sregs without setting vCPU registers in
KVM.

No functional change intended.

Signed-off-by: Ackerley Tng <ackerleytng@...gle.com>
Signed-off-by: Sagi Shahar <sagis@...gle.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 b46f1e5120d1..3162c6e8ea23 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 55971df6906c..1d6ae28aa398 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;
+}
+
+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);
 }
 
-- 
2.49.0.504.g3bcea36a83-goog