[PATCH v4 21/30] KVM: x86: Move LLDT assembly wrappers into VMX

[Sean Christopherson <seanjc@google.com>]

Move kvm_{load,read}_ldt() into vmx.c, as vmx_{load,store}_ldt(), as they
are exclusively used by VMX to save/restore host state, and have no
business being globally visible.

Ideally, KVM-specific helpers wouldn't exist at all, as they are nothing
more than assembly wrappers for SLDT and LLDT, i.e. should be provided by
the kernel, not by KVM.  Punt that cleanup to the future, as
arch/x86/include/asm/desc.h _does_ provide helpers, but load_ldt() is only
available for CONFIG_PARAVIRT_XXL=n builds, and both {load,store}_ldt()
unnecessarily constrain the operands to memory.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 arch/x86/include/asm/kvm_host.h | 12 ------------
 arch/x86/kvm/vmx/vmx.c          | 18 +++++++++++++++---
 2 files changed, 15 insertions(+), 15 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 1dd231ecf4b2..d1fdb2c3fdfa 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -2312,18 +2312,6 @@ static inline void kvm_dec_apicv_irq_window_req(struct kvm *kvm)
 
 #define kvm_arch_has_readonly_mem(kvm) (!(kvm)->arch.has_protected_state)
 
-static inline u16 kvm_read_ldt(void)
-{
-	u16 ldt;
-	asm("sldt %0" : "=g"(ldt));
-	return ldt;
-}
-
-static inline void kvm_load_ldt(u16 sel)
-{
-	asm("lldt %0" : : "rm"(sel));
-}
-
 #ifdef CONFIG_X86_64
 static inline unsigned long read_msr(unsigned long msr)
 {
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index c548f22375ad..2c120ff47790 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -1186,6 +1186,18 @@ static void vmx_remove_autostore_msr(struct vcpu_vmx *vmx, u32 msr)
 	vmx_remove_auto_msr(&vmx->msr_autostore, msr, VM_EXIT_MSR_STORE_COUNT);
 }
 
+static u16 vmx_store_ldt(void)
+{
+	u16 ldt;
+	asm("sldt %0" : "=g"(ldt));
+	return ldt;
+}
+
+static void vmx_load_ldt(u16 sel)
+{
+	asm("lldt %0" : : "rm"(sel));
+}
+
 #ifdef CONFIG_X86_32
 /*
  * On 32-bit kernels, VM exits still load the FS and GS bases from the
@@ -1203,7 +1215,7 @@ static unsigned long segment_base(u16 selector)
 	table = get_current_gdt_ro();
 
 	if ((selector & SEGMENT_TI_MASK) == SEGMENT_LDT) {
-		u16 ldt_selector = kvm_read_ldt();
+		u16 ldt_selector = vmx_store_ldt();
 
 		if (!(ldt_selector & ~SEGMENT_RPL_MASK))
 			return 0;
@@ -1358,7 +1370,7 @@ void vmx_prepare_switch_to_guest(struct kvm_vcpu *vcpu)
 	 * Set host fs and gs selectors.  Unfortunately, 22.2.3 does not
 	 * allow segment selectors with cpl > 0 or ti == 1.
 	 */
-	host_state->ldt_sel = kvm_read_ldt();
+	host_state->ldt_sel = vmx_store_ldt();
 
 #ifdef CONFIG_X86_64
 	savesegment(ds, host_state->ds_sel);
@@ -1405,7 +1417,7 @@ static void vmx_prepare_switch_to_host(struct vcpu_vmx *vmx)
 	rdmsrq(MSR_KERNEL_GS_BASE, vmx->msr_guest_kernel_gs_base);
 #endif
 	if (host_state->ldt_sel || (host_state->gs_sel & 7)) {
-		kvm_load_ldt(host_state->ldt_sel);
+		vmx_load_ldt(host_state->ldt_sel);
 #ifdef CONFIG_X86_64
 		load_gs_index(host_state->gs_sel);
 #else
-- 
2.54.0.1136.gdb2ca164c4-goog