[PATCH v16 08/20] KVM: selftests: Expose functions to get default sregs values

[Lisa Wang <wyihan@google.com>]

From: Sagi Shahar <sagis@google.com>

TDX can't set sregs values directly using KVM_SET_SREGS. Expose the
default values of certain sregs used by TDX VMs so they can be set
manually.

Signed-off-by: Sagi Shahar <sagis@google.com>
Signed-off-by: Lisa Wang <wyihan@google.com>
Reviewed-by: Binbin Wu <binbin.wu@linux.intel.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Xiaoyao Li <xiaoyao.li@intel.com>
---
 .../testing/selftests/kvm/include/x86/processor.h  | 35 ++++++++++++++++++++++
 tools/testing/selftests/kvm/lib/x86/processor.c    | 20 ++++---------
 2 files changed, 41 insertions(+), 14 deletions(-)

diff --git a/tools/testing/selftests/kvm/include/x86/processor.h b/tools/testing/selftests/kvm/include/x86/processor.h
index e62ca763135e..4db0c7009876 100644
--- a/tools/testing/selftests/kvm/include/x86/processor.h
+++ b/tools/testing/selftests/kvm/include/x86/processor.h
@@ -32,6 +32,10 @@ extern struct kvm_mmu guest_mmu;
 #define MAX_NR_CPUID_ENTRIES 100
 #endif
 
+#ifndef NUM_INTERRUPTS
+#define NUM_INTERRUPTS 256
+#endif
+
 #define NONCANONICAL 0xaaaaaaaaaaaaaaaaull
 
 /* Forced emulation prefix, used to invoke the emulator unconditionally. */
@@ -1672,4 +1676,35 @@ u64 *tdp_get_pte(struct kvm_vm *vm, u64 l2_gpa);
 
 bool sys_clocksource_is_based_on_tsc(void);
 
+static inline u16 kvm_get_default_idt_limit(void)
+{
+	return NUM_INTERRUPTS * sizeof(struct idt_entry) - 1;
+}
+
+static inline u16 kvm_get_default_gdt_limit(void)
+{
+	return getpagesize() - 1;
+}
+
+static inline u64 kvm_get_default_cr0(void)
+{
+	return X86_CR0_PE | X86_CR0_NE | X86_CR0_PG;
+}
+
+static inline u64 kvm_get_default_cr4(int pgtable_levels)
+{
+	u64 cr4 = X86_CR4_PAE | X86_CR4_OSFXSR;
+
+	if (kvm_cpu_has(X86_FEATURE_XSAVE))
+		cr4 |= X86_CR4_OSXSAVE;
+	if (pgtable_levels == 5)
+		cr4 |= X86_CR4_LA57;
+	return cr4;
+}
+
+static inline u64 kvm_get_default_efer(void)
+{
+	return EFER_LME | EFER_LMA | EFER_NX;
+}
+
 #endif /* SELFTEST_KVM_PROCESSOR_H */
diff --git a/tools/testing/selftests/kvm/lib/x86/processor.c b/tools/testing/selftests/kvm/lib/x86/processor.c
index fe56df0c7aa4..b8dbb16d5a28 100644
--- a/tools/testing/selftests/kvm/lib/x86/processor.c
+++ b/tools/testing/selftests/kvm/lib/x86/processor.c
@@ -15,10 +15,6 @@
 #include "tdx/tdx_util.h"
 #include "vmx.h"
 
-#ifndef NUM_INTERRUPTS
-#define NUM_INTERRUPTS 256
-#endif
-
 gva_t exception_handlers;
 bool host_cpu_is_amd;
 bool host_cpu_is_intel;
@@ -655,17 +651,13 @@ 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.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;
-	if (vm->mmu.pgtable_levels == 5)
-		sregs.cr4 |= X86_CR4_LA57;
-	sregs.efer |= (EFER_LME | EFER_LMA | EFER_NX);
+	sregs.gdt.limit = kvm_get_default_gdt_limit();
+
+	sregs.cr0 = kvm_get_default_cr0();
+	sregs.cr4 |= kvm_get_default_cr4(vm->mmu.pgtable_levels);
+	sregs.efer |= kvm_get_default_efer();
 
 	kvm_seg_set_unusable(&sregs.ldt);
 	kvm_seg_set_kernel_code_64bit(&sregs.cs);

-- 
2.56.0.455.g6c5a503b38-goog