From 781ee15bd9a9fa8c0576838d24b58b3bb5a30e05 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Fri, 12 Jun 2026 17:03:20 -0700 Subject: [PATCH] KVM: x86: Move LLDT assembly wrappers into VMX 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 Reviewed-by: Binbin Wu Message-ID: <20260613000329.732085-22-seanjc@google.com> Signed-off-by: Paolo Bonzini --- 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 7907d1c52c5f..8ddcc3072482 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -2311,18 +2311,6 @@ 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 125994ed3db5..b2562d158151 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