KVM: VMX: Fix host userspace gsbase corruption

[lisovros/linux_canprio.git] / arch / x86 / kvm / vmx.c

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index f6ce8bf00c383b275826c4d57ac3c4aa3b567890..f23f725dfd8c9be11bc18a528b247ea3855cf401 100644 (file)
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -828,10 +828,9 @@ static void vmx_save_host_state(struct kvm_vcpu *vcpu)
 #endif
 
 #ifdef CONFIG_X86_64
-       if (is_long_mode(&vmx->vcpu)) {
-               rdmsrl(MSR_KERNEL_GS_BASE, vmx->msr_host_kernel_gs_base);
+       rdmsrl(MSR_KERNEL_GS_BASE, vmx->msr_host_kernel_gs_base);
+       if (is_long_mode(&vmx->vcpu))
                wrmsrl(MSR_KERNEL_GS_BASE, vmx->msr_guest_kernel_gs_base);
-       }
 #endif
        for (i = 0; i < vmx->save_nmsrs; ++i)
                kvm_set_shared_msr(vmx->guest_msrs[i].index,
@@ -846,11 +845,14 @@ static void __vmx_load_host_state(struct vcpu_vmx *vmx)
 
        ++vmx->vcpu.stat.host_state_reload;
        vmx->host_state.loaded = 0;
+#ifdef CONFIG_X86_64
+       if (is_long_mode(&vmx->vcpu))
+               rdmsrl(MSR_KERNEL_GS_BASE, vmx->msr_guest_kernel_gs_base);
+#endif
        if (vmx->host_state.gs_ldt_reload_needed) {
                kvm_load_ldt(vmx->host_state.ldt_sel);
 #ifdef CONFIG_X86_64
                load_gs_index(vmx->host_state.gs_sel);
-               wrmsrl(MSR_KERNEL_GS_BASE, current->thread.gs);
 #else
                loadsegment(gs, vmx->host_state.gs_sel);
 #endif
@@ -859,10 +861,7 @@ static void __vmx_load_host_state(struct vcpu_vmx *vmx)
                loadsegment(fs, vmx->host_state.fs_sel);
        reload_tss();
 #ifdef CONFIG_X86_64
-       if (is_long_mode(&vmx->vcpu)) {
-               rdmsrl(MSR_KERNEL_GS_BASE, vmx->msr_guest_kernel_gs_base);
-               wrmsrl(MSR_KERNEL_GS_BASE, vmx->msr_host_kernel_gs_base);
-       }
+       wrmsrl(MSR_KERNEL_GS_BASE, vmx->msr_host_kernel_gs_base);
 #endif
        if (current_thread_info()->status & TS_USEDFPU)
                clts();