diff options
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/include/asm/desc.h | 106 | ||||
| -rw-r--r-- | arch/x86/include/asm/processor.h | 1 | ||||
| -rw-r--r-- | arch/x86/kernel/cpu/common.c | 28 | ||||
| -rw-r--r-- | arch/x86/kvm/svm.c | 4 | ||||
| -rw-r--r-- | arch/x86/kvm/vmx.c | 12 |
5 files changed, 96 insertions, 55 deletions
diff --git a/arch/x86/include/asm/desc.h b/arch/x86/include/asm/desc.h index 4b5ef0c64291..ec05f9c1a62c 100644 --- a/arch/x86/include/asm/desc.h +++ b/arch/x86/include/asm/desc.h @@ -248,9 +248,77 @@ static inline void native_set_ldt(const void *addr, unsigned int entries) } } +static inline void native_load_gdt(const struct desc_ptr *dtr) +{ + asm volatile("lgdt %0"::"m" (*dtr)); +} + +static inline void native_load_idt(const struct desc_ptr *dtr) +{ + asm volatile("lidt %0"::"m" (*dtr)); +} + +static inline void native_store_gdt(struct desc_ptr *dtr) +{ + asm volatile("sgdt %0":"=m" (*dtr)); +} + +static inline void native_store_idt(struct desc_ptr *dtr) +{ + asm volatile("sidt %0":"=m" (*dtr)); +} + +/* + * The LTR instruction marks the TSS GDT entry as busy. On 64-bit, the GDT is + * a read-only remapping. To prevent a page fault, the GDT is switched to the + * original writeable version when needed. + */ +#ifdef CONFIG_X86_64 static inline void native_load_tr_desc(void) { + struct desc_ptr gdt; + int cpu = raw_smp_processor_id(); + bool restore = 0; + struct desc_struct *fixmap_gdt; + + native_store_gdt(&gdt); + fixmap_gdt = get_cpu_gdt_ro(cpu); + + /* + * If the current GDT is the read-only fixmap, swap to the original + * writeable version. Swap back at the end. + */ + if (gdt.address == (unsigned long)fixmap_gdt) { + load_direct_gdt(cpu); + restore = 1; + } asm volatile("ltr %w0"::"q" (GDT_ENTRY_TSS*8)); + if (restore) + load_fixmap_gdt(cpu); +} +#else +static inline void native_load_tr_desc(void) +{ + asm volatile("ltr %w0"::"q" (GDT_ENTRY_TSS*8)); +} +#endif + +static inline unsigned long native_store_tr(void) +{ + unsigned long tr; + + asm volatile("str %0":"=r" (tr)); + + return tr; +} + +static inline void native_load_tls(struct thread_struct *t, unsigned int cpu) +{ + struct desc_struct *gdt = get_cpu_gdt_rw(cpu); + unsigned int i; + + for (i = 0; i < GDT_ENTRY_TLS_ENTRIES; i++) + gdt[GDT_ENTRY_TLS_MIN + i] = t->tls_array[i]; } DECLARE_PER_CPU(bool, __tss_limit_invalid); @@ -305,44 +373,6 @@ static inline void invalidate_tss_limit(void) this_cpu_write(__tss_limit_invalid, true); } -static inline void native_load_gdt(const struct desc_ptr *dtr) -{ - asm volatile("lgdt %0"::"m" (*dtr)); -} - -static inline void native_load_idt(const struct desc_ptr *dtr) -{ - asm volatile("lidt %0"::"m" (*dtr)); -} - -static inline void native_store_gdt(struct desc_ptr *dtr) -{ - asm volatile("sgdt %0":"=m" (*dtr)); -} - -static inline void native_store_idt(struct desc_ptr *dtr) -{ - asm volatile("sidt %0":"=m" (*dtr)); -} - -static inline unsigned long native_store_tr(void) -{ - unsigned long tr; - - asm volatile("str %0":"=r" (tr)); - - return tr; -} - -static inline void native_load_tls(struct thread_struct *t, unsigned int cpu) -{ - struct desc_struct *gdt = get_cpu_gdt_rw(cpu); - unsigned int i; - - for (i = 0; i < GDT_ENTRY_TLS_ENTRIES; i++) - gdt[GDT_ENTRY_TLS_MIN + i] = t->tls_array[i]; -} - /* This intentionally ignores lm, since 32-bit apps don't have that field. */ #define LDT_empty(info) \ ((info)->base_addr == 0 && \ diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h index 1150e1b21b0d..edf42c4ac8c8 100644 --- a/arch/x86/include/asm/processor.h +++ b/arch/x86/include/asm/processor.h @@ -716,6 +716,7 @@ extern struct desc_ptr early_gdt_descr; extern void cpu_set_gdt(int); extern void switch_to_new_gdt(int); +extern void load_direct_gdt(int); extern void load_fixmap_gdt(int); extern void load_percpu_segment(int); extern void cpu_init(void); diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index 3cf1590ec9ce..f8e22dbad86c 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -448,8 +448,15 @@ void load_percpu_segment(int cpu) load_stack_canary_segment(); } -/* Used by XEN to force the GDT read-only when required */ +/* + * On 64-bit the GDT remapping is read-only. + * A global is used for Xen to change the default when required. + */ +#ifdef CONFIG_X86_64 +pgprot_t pg_fixmap_gdt_flags = PAGE_KERNEL_RO; +#else pgprot_t pg_fixmap_gdt_flags = PAGE_KERNEL; +#endif /* Setup the fixmap mapping only once per-processor */ static inline void setup_fixmap_gdt(int cpu) @@ -458,6 +465,17 @@ static inline void setup_fixmap_gdt(int cpu) __pa(get_cpu_gdt_rw(cpu)), pg_fixmap_gdt_flags); } +/* Load the original GDT from the per-cpu structure */ +void load_direct_gdt(int cpu) +{ + struct desc_ptr gdt_descr; + + gdt_descr.address = (long)get_cpu_gdt_rw(cpu); + gdt_descr.size = GDT_SIZE - 1; + load_gdt(&gdt_descr); +} +EXPORT_SYMBOL_GPL(load_direct_gdt); + /* Load a fixmap remapping of the per-cpu GDT */ void load_fixmap_gdt(int cpu) { @@ -467,6 +485,7 @@ void load_fixmap_gdt(int cpu) gdt_descr.size = GDT_SIZE - 1; load_gdt(&gdt_descr); } +EXPORT_SYMBOL_GPL(load_fixmap_gdt); /* * Current gdt points %fs at the "master" per-cpu area: after this, @@ -474,11 +493,8 @@ void load_fixmap_gdt(int cpu) */ void switch_to_new_gdt(int cpu) { - struct desc_ptr gdt_descr; - - gdt_descr.address = (long)get_cpu_gdt_rw(cpu); - gdt_descr.size = GDT_SIZE - 1; - load_gdt(&gdt_descr); + /* Load the original GDT */ + load_direct_gdt(cpu); /* Reload the per-cpu base */ load_percpu_segment(cpu); } diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index d1efe2c62b3f..c02b9af2056a 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -741,7 +741,6 @@ static int svm_hardware_enable(void) struct svm_cpu_data *sd; uint64_t efer; - struct desc_ptr gdt_descr; struct desc_struct *gdt; int me = raw_smp_processor_id(); @@ -763,8 +762,7 @@ static int svm_hardware_enable(void) sd->max_asid = cpuid_ebx(SVM_CPUID_FUNC) - 1; sd->next_asid = sd->max_asid + 1; - native_store_gdt(&gdt_descr); - gdt = (struct desc_struct *)gdt_descr.address; + gdt = get_current_gdt_rw(); sd->tss_desc = (struct kvm_ldttss_desc *)(gdt + GDT_ENTRY_TSS); wrmsrl(MSR_EFER, efer | EFER_SVME); diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 98e82ee1e699..596a76d82b11 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -935,7 +935,6 @@ static DEFINE_PER_CPU(struct vmcs *, current_vmcs); * when a CPU is brought down, and we need to VMCLEAR all VMCSs loaded on it. */ static DEFINE_PER_CPU(struct list_head, loaded_vmcss_on_cpu); -static DEFINE_PER_CPU(struct desc_ptr, host_gdt); /* * We maintian a per-CPU linked-list of vCPU, so in wakeup_handler() we @@ -2052,14 +2051,13 @@ static bool update_transition_efer(struct vcpu_vmx *vmx, int efer_offset) */ static unsigned long segment_base(u16 selector) { - struct desc_ptr *gdt = this_cpu_ptr(&host_gdt); struct desc_struct *table; unsigned long v; if (!(selector & ~SEGMENT_RPL_MASK)) return 0; - table = (struct desc_struct *)gdt->address; + table = get_current_gdt_ro(); if ((selector & SEGMENT_TI_MASK) == SEGMENT_LDT) { u16 ldt_selector = kvm_read_ldt(); @@ -2164,7 +2162,7 @@ static void __vmx_load_host_state(struct vcpu_vmx *vmx) #endif if (vmx->host_state.msr_host_bndcfgs) wrmsrl(MSR_IA32_BNDCFGS, vmx->host_state.msr_host_bndcfgs); - load_gdt(this_cpu_ptr(&host_gdt)); + load_fixmap_gdt(raw_smp_processor_id()); } static void vmx_load_host_state(struct vcpu_vmx *vmx) @@ -2266,7 +2264,7 @@ static void vmx_vcpu_load(struct kvm_vcpu *vcpu, int cpu) } if (!already_loaded) { - struct desc_ptr *gdt = this_cpu_ptr(&host_gdt); + unsigned long gdt = get_current_gdt_ro_vaddr(); unsigned long sysenter_esp; kvm_make_request(KVM_REQ_TLB_FLUSH, vcpu); @@ -2277,7 +2275,7 @@ static void vmx_vcpu_load(struct kvm_vcpu *vcpu, int cpu) */ vmcs_writel(HOST_TR_BASE, (unsigned long)this_cpu_ptr(&cpu_tss)); - vmcs_writel(HOST_GDTR_BASE, gdt->address); + vmcs_writel(HOST_GDTR_BASE, gdt); /* 22.2.4 */ /* * VM exits change the host TR limit to 0x67 after a VM @@ -3465,8 +3463,6 @@ static int hardware_enable(void) ept_sync_global(); } - native_store_gdt(this_cpu_ptr(&host_gdt)); - return 0; } |