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Date:   Sat, 21 Jan 2023 00:15:14 +0000
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Subject: [RFC PATCH v3 03/31] KVM: selftests: Expose function that sets up
 sregs based on VM's mode
From:   Ackerley Tng <ackerleytng@google.com>
To:     linux-kselftest@vger.kernel.org
Cc:     pbonzini@redhat.com, seanjc@google.com, isaku.yamahata@intel.com,
        sagis@google.com, erdemaktas@google.com, afranji@google.com,
        runanwang@google.com, shuah@kernel.org, drjones@redhat.com,
        maz@kernel.org, bgardon@google.com, jmattson@google.com,
        dmatlack@google.com, peterx@redhat.com, oupton@google.com,
        ricarkol@google.com, yang.zhong@intel.com, wei.w.wang@intel.com,
        xiaoyao.li@intel.com, pgonda@google.com, marcorr@google.com,
        eesposit@redhat.com, borntraeger@de.ibm.com, eric.auger@redhat.com,
        wangyanan55@huawei.com, aaronlewis@google.com, vkuznets@redhat.com,
        pshier@google.com, axelrasmussen@google.com,
        zhenzhong.duan@intel.com, maciej.szmigiero@oracle.com,
        like.xu@linux.intel.com, linux-kernel@vger.kernel.org,
        kvm@vger.kernel.org, Ackerley Tng <ackerleytng@google.com>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

This allows initializing sregs without setting vCPU registers in
KVM.

No functional change intended.

Signed-off-by: Ackerley Tng <ackerleytng@google.com>
---
 .../selftests/kvm/include/x86_64/processor.h  |  2 +
 .../selftests/kvm/lib/x86_64/processor.c      | 39 ++++++++++---------
 2 files changed, 23 insertions(+), 18 deletions(-)

diff --git a/tools/testing/selftests/kvm/include/x86_64/processor.h b/tools/testing/selftests/kvm/include/x86_64/processor.h
index e8ca0d8a6a7e0..74e0d3698f30c 100644
--- a/tools/testing/selftests/kvm/include/x86_64/processor.h
+++ b/tools/testing/selftests/kvm/include/x86_64/processor.h
@@ -644,6 +644,8 @@ const struct kvm_cpuid_entry2 *get_cpuid_entry(const struct kvm_cpuid2 *cpuid,
 void vcpu_init_cpuid(struct kvm_vcpu *vcpu, const struct kvm_cpuid2 *cpuid);
 void vcpu_set_hv_cpuid(struct kvm_vcpu *vcpu);
 
+void vcpu_setup_mode_sregs(struct kvm_vm *vm, struct kvm_sregs *sregs);
+
 static inline struct kvm_cpuid_entry2 *__vcpu_get_cpuid_entry(struct kvm_vcpu *vcpu,
 							      uint32_t function,
 							      uint32_t index)
diff --git a/tools/testing/selftests/kvm/lib/x86_64/processor.c b/tools/testing/selftests/kvm/lib/x86_64/processor.c
index ed811181320de..1bb07d3c025b0 100644
--- a/tools/testing/selftests/kvm/lib/x86_64/processor.c
+++ b/tools/testing/selftests/kvm/lib/x86_64/processor.c
@@ -589,35 +589,38 @@ static void kvm_setup_tss_64bit(struct kvm_vm *vm, struct kvm_segment *segp,
 	kvm_seg_fill_gdt_64bit(vm, segp);
 }
 
-static void vcpu_setup(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;
-
-	/* Set mode specific system register values. */
-	vcpu_sregs_get(vcpu, &sregs);
-
-	sregs.idt.limit = 0;
+	sregs->idt.limit = 0;
 
-	kvm_setup_gdt(vm, &sregs.gdt);
+	kvm_setup_gdt(vm, &sregs->gdt);
 
 	switch (vm->mode) {
 	case VM_MODE_PXXV48_4K:
-		sregs.cr0 = X86_CR0_PE | X86_CR0_NE | X86_CR0_PG;
-		sregs.cr4 |= X86_CR4_PAE | X86_CR4_OSFXSR;
-		sregs.efer |= (EFER_LME | EFER_LMA | EFER_NX);
-
-		kvm_seg_set_unusable(&sregs.ldt);
-		kvm_seg_set_kernel_code_64bit(vm, DEFAULT_CODE_SELECTOR, &sregs.cs);
-		kvm_seg_set_kernel_data_64bit(vm, DEFAULT_DATA_SELECTOR, &sregs.ds);
-		kvm_seg_set_kernel_data_64bit(vm, DEFAULT_DATA_SELECTOR, &sregs.es);
-		kvm_setup_tss_64bit(vm, &sregs.tr, 0x18);
+		sregs->cr0 = X86_CR0_PE | X86_CR0_NE | X86_CR0_PG;
+		sregs->cr4 |= X86_CR4_PAE | X86_CR4_OSFXSR;
+		sregs->efer |= (EFER_LME | EFER_LMA | EFER_NX);
+
+		kvm_seg_set_unusable(&sregs->ldt);
+		kvm_seg_set_kernel_code_64bit(vm, DEFAULT_CODE_SELECTOR, &sregs->cs);
+		kvm_seg_set_kernel_data_64bit(vm, DEFAULT_DATA_SELECTOR, &sregs->ds);
+		kvm_seg_set_kernel_data_64bit(vm, DEFAULT_DATA_SELECTOR, &sregs->es);
+		kvm_setup_tss_64bit(vm, &sregs->tr, 0x18);
 		break;
 
 	default:
 		TEST_FAIL("Unknown guest mode, mode: 0x%x", vm->mode);
 	}
 
-	sregs.cr3 = vm->pgd;
+	sregs->cr3 = vm->pgd;
+}
+
+static void vcpu_setup(struct kvm_vm *vm, struct kvm_vcpu *vcpu)
+{
+	struct kvm_sregs sregs;
+
+	vcpu_sregs_get(vcpu, &sregs);
+	vcpu_setup_mode_sregs(vm, &sregs);
 	vcpu_sregs_set(vcpu, &sregs);
 }
 
-- 
2.39.0.246.g2a6d74b583-goog