Merge branch 'kvm-updates/2.6.36' of git://git.kernel.org/pub/scm/virt/kvm/kvm

* 'kvm-updates/2.6.36' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: Fix fs/gs reload oops with invalid ldt

3 files changed, 19 insertions, 44 deletions

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 502e53f999c..c52e2eb40a1 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -652,20 +652,6 @@ static inline struct kvm_mmu_page *page_header(hpa_t shadow_page)
         return (struct kvm_mmu_page *)page_private(page);
 }
 
-static inline u16 kvm_read_fs(void)
-{
-        u16 seg;
-        asm("mov %%fs, %0" : "=g"(seg));
-        return seg;
-}
-
-static inline u16 kvm_read_gs(void)
-{
-        u16 seg;
-        asm("mov %%gs, %0" : "=g"(seg));
-        return seg;
-}
-
 static inline u16 kvm_read_ldt(void)
 {
         u16 ldt;
@@ -673,16 +659,6 @@ static inline u16 kvm_read_ldt(void)
         return ldt;
 }
 
-static inline void kvm_load_fs(u16 sel)
-{
-        asm("mov %0, %%fs" : : "rm"(sel));
-}
-
-static inline void kvm_load_gs(u16 sel)
-{
-        asm("mov %0, %%gs" : : "rm"(sel));
-}
-
 static inline void kvm_load_ldt(u16 sel)
 {
         asm("lldt %0" : : "rm"(sel));
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 81ed28cb36e..8a3f9f64f86 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -3163,8 +3163,8 @@ static void svm_vcpu_run(struct kvm_vcpu *vcpu)
         sync_lapic_to_cr8(vcpu);
 
         save_host_msrs(vcpu);
-        fs_selector = kvm_read_fs();
-        gs_selector = kvm_read_gs();
+        savesegment(fs, fs_selector);
+        savesegment(gs, gs_selector);
         ldt_selector = kvm_read_ldt();
         svm->vmcb->save.cr2 = vcpu->arch.cr2;
         /* required for live migration with NPT */
@@ -3251,10 +3251,15 @@ static void svm_vcpu_run(struct kvm_vcpu *vcpu)
         vcpu->arch.regs[VCPU_REGS_RSP] = svm->vmcb->save.rsp;
         vcpu->arch.regs[VCPU_REGS_RIP] = svm->vmcb->save.rip;
 
-        kvm_load_fs(fs_selector);
-        kvm_load_gs(gs_selector);
-        kvm_load_ldt(ldt_selector);
         load_host_msrs(vcpu);
+        loadsegment(fs, fs_selector);
+#ifdef CONFIG_X86_64
+        load_gs_index(gs_selector);
+        wrmsrl(MSR_KERNEL_GS_BASE, current->thread.gs);
+#else
+        loadsegment(gs, gs_selector);
+#endif
+        kvm_load_ldt(ldt_selector);
 
         reload_tss(vcpu);
 
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 49b25eee25a..7bddfab1201 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -803,7 +803,7 @@ static void vmx_save_host_state(struct kvm_vcpu *vcpu)
          */
         vmx->host_state.ldt_sel = kvm_read_ldt();
         vmx->host_state.gs_ldt_reload_needed = vmx->host_state.ldt_sel;
-        vmx->host_state.fs_sel = kvm_read_fs();
+        savesegment(fs, vmx->host_state.fs_sel);
         if (!(vmx->host_state.fs_sel & 7)) {
                 vmcs_write16(HOST_FS_SELECTOR, vmx->host_state.fs_sel);
                 vmx->host_state.fs_reload_needed = 0;
@@ -811,7 +811,7 @@ static void vmx_save_host_state(struct kvm_vcpu *vcpu)
                 vmcs_write16(HOST_FS_SELECTOR, 0);
                 vmx->host_state.fs_reload_needed = 1;
         }
-        vmx->host_state.gs_sel = kvm_read_gs();
+        savesegment(gs, vmx->host_state.gs_sel);
         if (!(vmx->host_state.gs_sel & 7))
                 vmcs_write16(HOST_GS_SELECTOR, vmx->host_state.gs_sel);
         else {
@@ -841,27 +841,21 @@ static void vmx_save_host_state(struct kvm_vcpu *vcpu)
 
 static void __vmx_load_host_state(struct vcpu_vmx *vmx)
 {
-        unsigned long flags;
-
         if (!vmx->host_state.loaded)
                 return;
 
         ++vmx->vcpu.stat.host_state_reload;
         vmx->host_state.loaded = 0;
         if (vmx->host_state.fs_reload_needed)
-                kvm_load_fs(vmx->host_state.fs_sel);
+                loadsegment(fs, vmx->host_state.fs_sel);
         if (vmx->host_state.gs_ldt_reload_needed) {
                 kvm_load_ldt(vmx->host_state.ldt_sel);
-                /*
-                 * If we have to reload gs, we must take care to
-                 * preserve our gs base.
-                 */
-                local_irq_save(flags);
-                kvm_load_gs(vmx->host_state.gs_sel);
 #ifdef CONFIG_X86_64
-                wrmsrl(MSR_GS_BASE, vmcs_readl(HOST_GS_BASE));
+                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
-                local_irq_restore(flags);
         }
         reload_tss();
 #ifdef CONFIG_X86_64
@@ -2589,8 +2583,8 @@ static int vmx_vcpu_setup(struct vcpu_vmx *vmx)
         vmcs_write16(HOST_CS_SELECTOR, __KERNEL_CS);  /* 22.2.4 */
         vmcs_write16(HOST_DS_SELECTOR, __KERNEL_DS);  /* 22.2.4 */
         vmcs_write16(HOST_ES_SELECTOR, __KERNEL_DS);  /* 22.2.4 */
-        vmcs_write16(HOST_FS_SELECTOR, kvm_read_fs());    /* 22.2.4 */
-        vmcs_write16(HOST_GS_SELECTOR, kvm_read_gs());    /* 22.2.4 */
+        vmcs_write16(HOST_FS_SELECTOR, 0);            /* 22.2.4 */
+        vmcs_write16(HOST_GS_SELECTOR, 0);            /* 22.2.4 */
         vmcs_write16(HOST_SS_SELECTOR, __KERNEL_DS);  /* 22.2.4 */
 #ifdef CONFIG_X86_64
         rdmsrl(MSR_FS_BASE, a);