2 * Core of Xen paravirt_ops implementation.
4 * This file contains the xen_paravirt_ops structure itself, and the
6 * - privileged instructions
11 * Jeremy Fitzhardinge <jeremy@xensource.com>, XenSource Inc, 2007
14 #include <linux/cpu.h>
15 #include <linux/kernel.h>
16 #include <linux/init.h>
17 #include <linux/smp.h>
18 #include <linux/preempt.h>
19 #include <linux/hardirq.h>
20 #include <linux/percpu.h>
21 #include <linux/delay.h>
22 #include <linux/start_kernel.h>
23 #include <linux/sched.h>
24 #include <linux/kprobes.h>
25 #include <linux/bootmem.h>
26 #include <linux/export.h>
28 #include <linux/page-flags.h>
29 #include <linux/highmem.h>
30 #include <linux/console.h>
31 #include <linux/pci.h>
32 #include <linux/gfp.h>
33 #include <linux/memblock.h>
34 #include <linux/edd.h>
35 #include <linux/frame.h>
38 #include <xen/events.h>
39 #include <xen/interface/xen.h>
40 #include <xen/interface/version.h>
41 #include <xen/interface/physdev.h>
42 #include <xen/interface/vcpu.h>
43 #include <xen/interface/memory.h>
44 #include <xen/interface/nmi.h>
45 #include <xen/interface/xen-mca.h>
46 #include <xen/features.h>
48 #include <xen/hvc-console.h>
51 #include <asm/paravirt.h>
54 #include <asm/xen/pci.h>
55 #include <asm/xen/hypercall.h>
56 #include <asm/xen/hypervisor.h>
57 #include <asm/xen/cpuid.h>
58 #include <asm/fixmap.h>
59 #include <asm/processor.h>
60 #include <asm/proto.h>
61 #include <asm/msr-index.h>
62 #include <asm/traps.h>
63 #include <asm/setup.h>
65 #include <asm/pgalloc.h>
66 #include <asm/pgtable.h>
67 #include <asm/tlbflush.h>
68 #include <asm/reboot.h>
69 #include <asm/stackprotector.h>
70 #include <asm/hypervisor.h>
71 #include <asm/mach_traps.h>
72 #include <asm/mwait.h>
73 #include <asm/pci_x86.h>
77 #include <linux/acpi.h>
79 #include <acpi/pdc_intel.h>
80 #include <acpi/processor.h>
81 #include <xen/interface/platform.h>
87 #include "multicalls.h"
90 void *xen_initial_gdt
;
92 RESERVE_BRK(shared_info_page_brk
, PAGE_SIZE
);
94 static int xen_cpu_up_prepare_pv(unsigned int cpu
);
95 static int xen_cpu_dead_pv(unsigned int cpu
);
98 struct desc_struct desc
[3];
102 * Updating the 3 TLS descriptors in the GDT on every task switch is
103 * surprisingly expensive so we avoid updating them if they haven't
104 * changed. Since Xen writes different descriptors than the one
105 * passed in the update_descriptor hypercall we keep shadow copies to
108 static DEFINE_PER_CPU(struct tls_descs
, shadow_tls_desc
);
111 * On restore, set the vcpu placement up again.
112 * If it fails, then we're in a bad state, since
113 * we can't back out from using it...
115 void xen_vcpu_restore(void)
119 for_each_possible_cpu(cpu
) {
120 bool other_cpu
= (cpu
!= smp_processor_id());
121 bool is_up
= HYPERVISOR_vcpu_op(VCPUOP_is_up
, xen_vcpu_nr(cpu
),
124 if (other_cpu
&& is_up
&&
125 HYPERVISOR_vcpu_op(VCPUOP_down
, xen_vcpu_nr(cpu
), NULL
))
128 xen_setup_runstate_info(cpu
);
130 if (xen_have_vcpu_info_placement
)
133 if (other_cpu
&& is_up
&&
134 HYPERVISOR_vcpu_op(VCPUOP_up
, xen_vcpu_nr(cpu
), NULL
))
139 static void __init
xen_banner(void)
141 unsigned version
= HYPERVISOR_xen_version(XENVER_version
, NULL
);
142 struct xen_extraversion extra
;
143 HYPERVISOR_xen_version(XENVER_extraversion
, &extra
);
145 pr_info("Booting paravirtualized kernel %son %s\n",
146 xen_feature(XENFEAT_auto_translated_physmap
) ?
147 "with PVH extensions " : "", pv_info
.name
);
148 printk(KERN_INFO
"Xen version: %d.%d%s%s\n",
149 version
>> 16, version
& 0xffff, extra
.extraversion
,
150 xen_feature(XENFEAT_mmu_pt_update_preserve_ad
) ? " (preserve-AD)" : "");
152 /* Check if running on Xen version (major, minor) or later */
154 xen_running_on_version_or_later(unsigned int major
, unsigned int minor
)
156 unsigned int version
;
161 version
= HYPERVISOR_xen_version(XENVER_version
, NULL
);
162 if ((((version
>> 16) == major
) && ((version
& 0xffff) >= minor
)) ||
163 ((version
>> 16) > major
))
168 static __read_mostly
unsigned int cpuid_leaf5_ecx_val
;
169 static __read_mostly
unsigned int cpuid_leaf5_edx_val
;
171 static void xen_cpuid(unsigned int *ax
, unsigned int *bx
,
172 unsigned int *cx
, unsigned int *dx
)
174 unsigned maskebx
= ~0;
177 * Mask out inconvenient features, to try and disable as many
178 * unsupported kernel subsystems as possible.
181 case CPUID_MWAIT_LEAF
:
182 /* Synthesize the values.. */
185 *cx
= cpuid_leaf5_ecx_val
;
186 *dx
= cpuid_leaf5_edx_val
;
190 /* Suppress extended topology stuff */
195 asm(XEN_EMULATE_PREFIX
"cpuid"
200 : "0" (*ax
), "2" (*cx
));
204 STACK_FRAME_NON_STANDARD(xen_cpuid
); /* XEN_EMULATE_PREFIX */
206 static bool __init
xen_check_mwait(void)
209 struct xen_platform_op op
= {
210 .cmd
= XENPF_set_processor_pminfo
,
211 .u
.set_pminfo
.id
= -1,
212 .u
.set_pminfo
.type
= XEN_PM_PDC
,
215 unsigned int ax
, bx
, cx
, dx
;
216 unsigned int mwait_mask
;
218 /* We need to determine whether it is OK to expose the MWAIT
219 * capability to the kernel to harvest deeper than C3 states from ACPI
220 * _CST using the processor_harvest_xen.c module. For this to work, we
221 * need to gather the MWAIT_LEAF values (which the cstate.c code
222 * checks against). The hypervisor won't expose the MWAIT flag because
223 * it would break backwards compatibility; so we will find out directly
224 * from the hardware and hypercall.
226 if (!xen_initial_domain())
230 * When running under platform earlier than Xen4.2, do not expose
231 * mwait, to avoid the risk of loading native acpi pad driver
233 if (!xen_running_on_version_or_later(4, 2))
239 native_cpuid(&ax
, &bx
, &cx
, &dx
);
241 mwait_mask
= (1 << (X86_FEATURE_EST
% 32)) |
242 (1 << (X86_FEATURE_MWAIT
% 32));
244 if ((cx
& mwait_mask
) != mwait_mask
)
247 /* We need to emulate the MWAIT_LEAF and for that we need both
248 * ecx and edx. The hypercall provides only partial information.
251 ax
= CPUID_MWAIT_LEAF
;
256 native_cpuid(&ax
, &bx
, &cx
, &dx
);
258 /* Ask the Hypervisor whether to clear ACPI_PDC_C_C2C3_FFH. If so,
259 * don't expose MWAIT_LEAF and let ACPI pick the IOPORT version of C3.
261 buf
[0] = ACPI_PDC_REVISION_ID
;
263 buf
[2] = (ACPI_PDC_C_CAPABILITY_SMP
| ACPI_PDC_EST_CAPABILITY_SWSMP
);
265 set_xen_guest_handle(op
.u
.set_pminfo
.pdc
, buf
);
267 if ((HYPERVISOR_platform_op(&op
) == 0) &&
268 (buf
[2] & (ACPI_PDC_C_C1_FFH
| ACPI_PDC_C_C2C3_FFH
))) {
269 cpuid_leaf5_ecx_val
= cx
;
270 cpuid_leaf5_edx_val
= dx
;
278 static bool __init
xen_check_xsave(void)
280 unsigned int cx
, xsave_mask
;
284 xsave_mask
= (1 << (X86_FEATURE_XSAVE
% 32)) |
285 (1 << (X86_FEATURE_OSXSAVE
% 32));
287 /* Xen will set CR4.OSXSAVE if supported and not disabled by force */
288 return (cx
& xsave_mask
) == xsave_mask
;
291 static void __init
xen_init_capabilities(void)
293 setup_force_cpu_cap(X86_FEATURE_XENPV
);
294 setup_clear_cpu_cap(X86_FEATURE_DCA
);
295 setup_clear_cpu_cap(X86_FEATURE_APERFMPERF
);
296 setup_clear_cpu_cap(X86_FEATURE_MTRR
);
297 setup_clear_cpu_cap(X86_FEATURE_ACC
);
298 setup_clear_cpu_cap(X86_FEATURE_X2APIC
);
300 if (!xen_initial_domain())
301 setup_clear_cpu_cap(X86_FEATURE_ACPI
);
303 if (xen_check_mwait())
304 setup_force_cpu_cap(X86_FEATURE_MWAIT
);
306 setup_clear_cpu_cap(X86_FEATURE_MWAIT
);
308 if (!xen_check_xsave()) {
309 setup_clear_cpu_cap(X86_FEATURE_XSAVE
);
310 setup_clear_cpu_cap(X86_FEATURE_OSXSAVE
);
314 static void xen_set_debugreg(int reg
, unsigned long val
)
316 HYPERVISOR_set_debugreg(reg
, val
);
319 static unsigned long xen_get_debugreg(int reg
)
321 return HYPERVISOR_get_debugreg(reg
);
324 static void xen_end_context_switch(struct task_struct
*next
)
327 paravirt_end_context_switch(next
);
330 static unsigned long xen_store_tr(void)
336 * Set the page permissions for a particular virtual address. If the
337 * address is a vmalloc mapping (or other non-linear mapping), then
338 * find the linear mapping of the page and also set its protections to
341 static void set_aliased_prot(void *v
, pgprot_t prot
)
350 ptep
= lookup_address((unsigned long)v
, &level
);
351 BUG_ON(ptep
== NULL
);
353 pfn
= pte_pfn(*ptep
);
354 page
= pfn_to_page(pfn
);
356 pte
= pfn_pte(pfn
, prot
);
359 * Careful: update_va_mapping() will fail if the virtual address
360 * we're poking isn't populated in the page tables. We don't
361 * need to worry about the direct map (that's always in the page
362 * tables), but we need to be careful about vmap space. In
363 * particular, the top level page table can lazily propagate
364 * entries between processes, so if we've switched mms since we
365 * vmapped the target in the first place, we might not have the
366 * top-level page table entry populated.
368 * We disable preemption because we want the same mm active when
369 * we probe the target and when we issue the hypercall. We'll
370 * have the same nominal mm, but if we're a kernel thread, lazy
371 * mm dropping could change our pgd.
373 * Out of an abundance of caution, this uses __get_user() to fault
374 * in the target address just in case there's some obscure case
375 * in which the target address isn't readable.
380 probe_kernel_read(&dummy
, v
, 1);
382 if (HYPERVISOR_update_va_mapping((unsigned long)v
, pte
, 0))
385 if (!PageHighMem(page
)) {
386 void *av
= __va(PFN_PHYS(pfn
));
389 if (HYPERVISOR_update_va_mapping((unsigned long)av
, pte
, 0))
397 static void xen_alloc_ldt(struct desc_struct
*ldt
, unsigned entries
)
399 const unsigned entries_per_page
= PAGE_SIZE
/ LDT_ENTRY_SIZE
;
403 * We need to mark the all aliases of the LDT pages RO. We
404 * don't need to call vm_flush_aliases(), though, since that's
405 * only responsible for flushing aliases out the TLBs, not the
406 * page tables, and Xen will flush the TLB for us if needed.
408 * To avoid confusing future readers: none of this is necessary
409 * to load the LDT. The hypervisor only checks this when the
410 * LDT is faulted in due to subsequent descriptor access.
413 for (i
= 0; i
< entries
; i
+= entries_per_page
)
414 set_aliased_prot(ldt
+ i
, PAGE_KERNEL_RO
);
417 static void xen_free_ldt(struct desc_struct
*ldt
, unsigned entries
)
419 const unsigned entries_per_page
= PAGE_SIZE
/ LDT_ENTRY_SIZE
;
422 for (i
= 0; i
< entries
; i
+= entries_per_page
)
423 set_aliased_prot(ldt
+ i
, PAGE_KERNEL
);
426 static void xen_set_ldt(const void *addr
, unsigned entries
)
428 struct mmuext_op
*op
;
429 struct multicall_space mcs
= xen_mc_entry(sizeof(*op
));
431 trace_xen_cpu_set_ldt(addr
, entries
);
434 op
->cmd
= MMUEXT_SET_LDT
;
435 op
->arg1
.linear_addr
= (unsigned long)addr
;
436 op
->arg2
.nr_ents
= entries
;
438 MULTI_mmuext_op(mcs
.mc
, op
, 1, NULL
, DOMID_SELF
);
440 xen_mc_issue(PARAVIRT_LAZY_CPU
);
443 static void xen_load_gdt(const struct desc_ptr
*dtr
)
445 unsigned long va
= dtr
->address
;
446 unsigned int size
= dtr
->size
+ 1;
447 unsigned pages
= DIV_ROUND_UP(size
, PAGE_SIZE
);
448 unsigned long frames
[pages
];
452 * A GDT can be up to 64k in size, which corresponds to 8192
453 * 8-byte entries, or 16 4k pages..
456 BUG_ON(size
> 65536);
457 BUG_ON(va
& ~PAGE_MASK
);
459 for (f
= 0; va
< dtr
->address
+ size
; va
+= PAGE_SIZE
, f
++) {
462 unsigned long pfn
, mfn
;
466 * The GDT is per-cpu and is in the percpu data area.
467 * That can be virtually mapped, so we need to do a
468 * page-walk to get the underlying MFN for the
469 * hypercall. The page can also be in the kernel's
470 * linear range, so we need to RO that mapping too.
472 ptep
= lookup_address(va
, &level
);
473 BUG_ON(ptep
== NULL
);
475 pfn
= pte_pfn(*ptep
);
476 mfn
= pfn_to_mfn(pfn
);
477 virt
= __va(PFN_PHYS(pfn
));
481 make_lowmem_page_readonly((void *)va
);
482 make_lowmem_page_readonly(virt
);
485 if (HYPERVISOR_set_gdt(frames
, size
/ sizeof(struct desc_struct
)))
490 * load_gdt for early boot, when the gdt is only mapped once
492 static void __init
xen_load_gdt_boot(const struct desc_ptr
*dtr
)
494 unsigned long va
= dtr
->address
;
495 unsigned int size
= dtr
->size
+ 1;
496 unsigned pages
= DIV_ROUND_UP(size
, PAGE_SIZE
);
497 unsigned long frames
[pages
];
501 * A GDT can be up to 64k in size, which corresponds to 8192
502 * 8-byte entries, or 16 4k pages..
505 BUG_ON(size
> 65536);
506 BUG_ON(va
& ~PAGE_MASK
);
508 for (f
= 0; va
< dtr
->address
+ size
; va
+= PAGE_SIZE
, f
++) {
510 unsigned long pfn
, mfn
;
512 pfn
= virt_to_pfn(va
);
513 mfn
= pfn_to_mfn(pfn
);
515 pte
= pfn_pte(pfn
, PAGE_KERNEL_RO
);
517 if (HYPERVISOR_update_va_mapping((unsigned long)va
, pte
, 0))
523 if (HYPERVISOR_set_gdt(frames
, size
/ sizeof(struct desc_struct
)))
527 static inline bool desc_equal(const struct desc_struct
*d1
,
528 const struct desc_struct
*d2
)
530 return d1
->a
== d2
->a
&& d1
->b
== d2
->b
;
533 static void load_TLS_descriptor(struct thread_struct
*t
,
534 unsigned int cpu
, unsigned int i
)
536 struct desc_struct
*shadow
= &per_cpu(shadow_tls_desc
, cpu
).desc
[i
];
537 struct desc_struct
*gdt
;
539 struct multicall_space mc
;
541 if (desc_equal(shadow
, &t
->tls_array
[i
]))
544 *shadow
= t
->tls_array
[i
];
546 gdt
= get_cpu_gdt_rw(cpu
);
547 maddr
= arbitrary_virt_to_machine(&gdt
[GDT_ENTRY_TLS_MIN
+i
]);
548 mc
= __xen_mc_entry(0);
550 MULTI_update_descriptor(mc
.mc
, maddr
.maddr
, t
->tls_array
[i
]);
553 static void xen_load_tls(struct thread_struct
*t
, unsigned int cpu
)
556 * XXX sleazy hack: If we're being called in a lazy-cpu zone
557 * and lazy gs handling is enabled, it means we're in a
558 * context switch, and %gs has just been saved. This means we
559 * can zero it out to prevent faults on exit from the
560 * hypervisor if the next process has no %gs. Either way, it
561 * has been saved, and the new value will get loaded properly.
562 * This will go away as soon as Xen has been modified to not
563 * save/restore %gs for normal hypercalls.
565 * On x86_64, this hack is not used for %gs, because gs points
566 * to KERNEL_GS_BASE (and uses it for PDA references), so we
567 * must not zero %gs on x86_64
569 * For x86_64, we need to zero %fs, otherwise we may get an
570 * exception between the new %fs descriptor being loaded and
571 * %fs being effectively cleared at __switch_to().
573 if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_CPU
) {
583 load_TLS_descriptor(t
, cpu
, 0);
584 load_TLS_descriptor(t
, cpu
, 1);
585 load_TLS_descriptor(t
, cpu
, 2);
587 xen_mc_issue(PARAVIRT_LAZY_CPU
);
591 static void xen_load_gs_index(unsigned int idx
)
593 if (HYPERVISOR_set_segment_base(SEGBASE_GS_USER_SEL
, idx
))
598 static void xen_write_ldt_entry(struct desc_struct
*dt
, int entrynum
,
601 xmaddr_t mach_lp
= arbitrary_virt_to_machine(&dt
[entrynum
]);
602 u64 entry
= *(u64
*)ptr
;
604 trace_xen_cpu_write_ldt_entry(dt
, entrynum
, entry
);
609 if (HYPERVISOR_update_descriptor(mach_lp
.maddr
, entry
))
615 static int cvt_gate_to_trap(int vector
, const gate_desc
*val
,
616 struct trap_info
*info
)
620 if (val
->type
!= GATE_TRAP
&& val
->type
!= GATE_INTERRUPT
)
623 info
->vector
= vector
;
625 addr
= gate_offset(*val
);
628 * Look for known traps using IST, and substitute them
629 * appropriately. The debugger ones are the only ones we care
630 * about. Xen will handle faults like double_fault,
631 * so we should never see them. Warn if
632 * there's an unexpected IST-using fault handler.
634 if (addr
== (unsigned long)debug
)
635 addr
= (unsigned long)xen_debug
;
636 else if (addr
== (unsigned long)int3
)
637 addr
= (unsigned long)xen_int3
;
638 else if (addr
== (unsigned long)stack_segment
)
639 addr
= (unsigned long)xen_stack_segment
;
640 else if (addr
== (unsigned long)double_fault
) {
641 /* Don't need to handle these */
643 #ifdef CONFIG_X86_MCE
644 } else if (addr
== (unsigned long)machine_check
) {
646 * when xen hypervisor inject vMCE to guest,
647 * use native mce handler to handle it
651 } else if (addr
== (unsigned long)nmi
)
653 * Use the native version as well.
657 /* Some other trap using IST? */
658 if (WARN_ON(val
->ist
!= 0))
661 #endif /* CONFIG_X86_64 */
662 info
->address
= addr
;
664 info
->cs
= gate_segment(*val
);
665 info
->flags
= val
->dpl
;
666 /* interrupt gates clear IF */
667 if (val
->type
== GATE_INTERRUPT
)
668 info
->flags
|= 1 << 2;
673 /* Locations of each CPU's IDT */
674 static DEFINE_PER_CPU(struct desc_ptr
, idt_desc
);
676 /* Set an IDT entry. If the entry is part of the current IDT, then
678 static void xen_write_idt_entry(gate_desc
*dt
, int entrynum
, const gate_desc
*g
)
680 unsigned long p
= (unsigned long)&dt
[entrynum
];
681 unsigned long start
, end
;
683 trace_xen_cpu_write_idt_entry(dt
, entrynum
, g
);
687 start
= __this_cpu_read(idt_desc
.address
);
688 end
= start
+ __this_cpu_read(idt_desc
.size
) + 1;
692 native_write_idt_entry(dt
, entrynum
, g
);
694 if (p
>= start
&& (p
+ 8) <= end
) {
695 struct trap_info info
[2];
699 if (cvt_gate_to_trap(entrynum
, g
, &info
[0]))
700 if (HYPERVISOR_set_trap_table(info
))
707 static void xen_convert_trap_info(const struct desc_ptr
*desc
,
708 struct trap_info
*traps
)
710 unsigned in
, out
, count
;
712 count
= (desc
->size
+1) / sizeof(gate_desc
);
715 for (in
= out
= 0; in
< count
; in
++) {
716 gate_desc
*entry
= (gate_desc
*)(desc
->address
) + in
;
718 if (cvt_gate_to_trap(in
, entry
, &traps
[out
]))
721 traps
[out
].address
= 0;
724 void xen_copy_trap_info(struct trap_info
*traps
)
726 const struct desc_ptr
*desc
= this_cpu_ptr(&idt_desc
);
728 xen_convert_trap_info(desc
, traps
);
731 /* Load a new IDT into Xen. In principle this can be per-CPU, so we
732 hold a spinlock to protect the static traps[] array (static because
733 it avoids allocation, and saves stack space). */
734 static void xen_load_idt(const struct desc_ptr
*desc
)
736 static DEFINE_SPINLOCK(lock
);
737 static struct trap_info traps
[257];
739 trace_xen_cpu_load_idt(desc
);
743 memcpy(this_cpu_ptr(&idt_desc
), desc
, sizeof(idt_desc
));
745 xen_convert_trap_info(desc
, traps
);
748 if (HYPERVISOR_set_trap_table(traps
))
754 /* Write a GDT descriptor entry. Ignore LDT descriptors, since
755 they're handled differently. */
756 static void xen_write_gdt_entry(struct desc_struct
*dt
, int entry
,
757 const void *desc
, int type
)
759 trace_xen_cpu_write_gdt_entry(dt
, entry
, desc
, type
);
770 xmaddr_t maddr
= arbitrary_virt_to_machine(&dt
[entry
]);
773 if (HYPERVISOR_update_descriptor(maddr
.maddr
, *(u64
*)desc
))
783 * Version of write_gdt_entry for use at early boot-time needed to
784 * update an entry as simply as possible.
786 static void __init
xen_write_gdt_entry_boot(struct desc_struct
*dt
, int entry
,
787 const void *desc
, int type
)
789 trace_xen_cpu_write_gdt_entry(dt
, entry
, desc
, type
);
798 xmaddr_t maddr
= virt_to_machine(&dt
[entry
]);
800 if (HYPERVISOR_update_descriptor(maddr
.maddr
, *(u64
*)desc
))
801 dt
[entry
] = *(struct desc_struct
*)desc
;
807 static void xen_load_sp0(struct tss_struct
*tss
,
808 struct thread_struct
*thread
)
810 struct multicall_space mcs
;
812 mcs
= xen_mc_entry(0);
813 MULTI_stack_switch(mcs
.mc
, __KERNEL_DS
, thread
->sp0
);
814 xen_mc_issue(PARAVIRT_LAZY_CPU
);
815 tss
->x86_tss
.sp0
= thread
->sp0
;
818 void xen_set_iopl_mask(unsigned mask
)
820 struct physdev_set_iopl set_iopl
;
822 /* Force the change at ring 0. */
823 set_iopl
.iopl
= (mask
== 0) ? 1 : (mask
>> 12) & 3;
824 HYPERVISOR_physdev_op(PHYSDEVOP_set_iopl
, &set_iopl
);
827 static void xen_io_delay(void)
831 static DEFINE_PER_CPU(unsigned long, xen_cr0_value
);
833 static unsigned long xen_read_cr0(void)
835 unsigned long cr0
= this_cpu_read(xen_cr0_value
);
837 if (unlikely(cr0
== 0)) {
838 cr0
= native_read_cr0();
839 this_cpu_write(xen_cr0_value
, cr0
);
845 static void xen_write_cr0(unsigned long cr0
)
847 struct multicall_space mcs
;
849 this_cpu_write(xen_cr0_value
, cr0
);
851 /* Only pay attention to cr0.TS; everything else is
853 mcs
= xen_mc_entry(0);
855 MULTI_fpu_taskswitch(mcs
.mc
, (cr0
& X86_CR0_TS
) != 0);
857 xen_mc_issue(PARAVIRT_LAZY_CPU
);
860 static void xen_write_cr4(unsigned long cr4
)
862 cr4
&= ~(X86_CR4_PGE
| X86_CR4_PSE
| X86_CR4_PCE
);
864 native_write_cr4(cr4
);
867 static inline unsigned long xen_read_cr8(void)
871 static inline void xen_write_cr8(unsigned long val
)
877 static u64
xen_read_msr_safe(unsigned int msr
, int *err
)
881 if (pmu_msr_read(msr
, &val
, err
))
884 val
= native_read_msr_safe(msr
, err
);
886 case MSR_IA32_APICBASE
:
887 #ifdef CONFIG_X86_X2APIC
888 if (!(cpuid_ecx(1) & (1 << (X86_FEATURE_X2APIC
& 31))))
890 val
&= ~X2APIC_ENABLE
;
896 static int xen_write_msr_safe(unsigned int msr
, unsigned low
, unsigned high
)
907 case MSR_FS_BASE
: which
= SEGBASE_FS
; goto set
;
908 case MSR_KERNEL_GS_BASE
: which
= SEGBASE_GS_USER
; goto set
;
909 case MSR_GS_BASE
: which
= SEGBASE_GS_KERNEL
; goto set
;
912 base
= ((u64
)high
<< 32) | low
;
913 if (HYPERVISOR_set_segment_base(which
, base
) != 0)
921 case MSR_SYSCALL_MASK
:
922 case MSR_IA32_SYSENTER_CS
:
923 case MSR_IA32_SYSENTER_ESP
:
924 case MSR_IA32_SYSENTER_EIP
:
925 /* Fast syscall setup is all done in hypercalls, so
926 these are all ignored. Stub them out here to stop
927 Xen console noise. */
931 if (!pmu_msr_write(msr
, low
, high
, &ret
))
932 ret
= native_write_msr_safe(msr
, low
, high
);
938 static u64
xen_read_msr(unsigned int msr
)
941 * This will silently swallow a #GP from RDMSR. It may be worth
946 return xen_read_msr_safe(msr
, &err
);
949 static void xen_write_msr(unsigned int msr
, unsigned low
, unsigned high
)
952 * This will silently swallow a #GP from WRMSR. It may be worth
955 xen_write_msr_safe(msr
, low
, high
);
958 void xen_setup_shared_info(void)
960 if (!xen_feature(XENFEAT_auto_translated_physmap
)) {
961 set_fixmap(FIX_PARAVIRT_BOOTMAP
,
962 xen_start_info
->shared_info
);
964 HYPERVISOR_shared_info
=
965 (struct shared_info
*)fix_to_virt(FIX_PARAVIRT_BOOTMAP
);
967 HYPERVISOR_shared_info
=
968 (struct shared_info
*)__va(xen_start_info
->shared_info
);
971 /* In UP this is as good a place as any to set up shared info */
972 xen_setup_vcpu_info_placement();
975 xen_setup_mfn_list_list();
978 * Now that shared info is set up we can start using routines that
979 * point to pvclock area.
981 if (system_state
== SYSTEM_BOOTING
)
985 /* This is called once we have the cpu_possible_mask */
986 void xen_setup_vcpu_info_placement(void)
990 for_each_possible_cpu(cpu
) {
991 /* Set up direct vCPU id mapping for PV guests. */
992 per_cpu(xen_vcpu_id
, cpu
) = cpu
;
997 * xen_vcpu_setup managed to place the vcpu_info within the
998 * percpu area for all cpus, so make use of it.
1000 if (xen_have_vcpu_info_placement
) {
1001 pv_irq_ops
.save_fl
= __PV_IS_CALLEE_SAVE(xen_save_fl_direct
);
1002 pv_irq_ops
.restore_fl
= __PV_IS_CALLEE_SAVE(xen_restore_fl_direct
);
1003 pv_irq_ops
.irq_disable
= __PV_IS_CALLEE_SAVE(xen_irq_disable_direct
);
1004 pv_irq_ops
.irq_enable
= __PV_IS_CALLEE_SAVE(xen_irq_enable_direct
);
1005 pv_mmu_ops
.read_cr2
= xen_read_cr2_direct
;
1009 static unsigned xen_patch(u8 type
, u16 clobbers
, void *insnbuf
,
1010 unsigned long addr
, unsigned len
)
1012 char *start
, *end
, *reloc
;
1015 start
= end
= reloc
= NULL
;
1017 #define SITE(op, x) \
1018 case PARAVIRT_PATCH(op.x): \
1019 if (xen_have_vcpu_info_placement) { \
1020 start = (char *)xen_##x##_direct; \
1021 end = xen_##x##_direct_end; \
1022 reloc = xen_##x##_direct_reloc; \
1027 SITE(pv_irq_ops
, irq_enable
);
1028 SITE(pv_irq_ops
, irq_disable
);
1029 SITE(pv_irq_ops
, save_fl
);
1030 SITE(pv_irq_ops
, restore_fl
);
1034 if (start
== NULL
|| (end
-start
) > len
)
1037 ret
= paravirt_patch_insns(insnbuf
, len
, start
, end
);
1039 /* Note: because reloc is assigned from something that
1040 appears to be an array, gcc assumes it's non-null,
1041 but doesn't know its relationship with start and
1043 if (reloc
> start
&& reloc
< end
) {
1044 int reloc_off
= reloc
- start
;
1045 long *relocp
= (long *)(insnbuf
+ reloc_off
);
1046 long delta
= start
- (char *)addr
;
1054 ret
= paravirt_patch_default(type
, clobbers
, insnbuf
,
1062 static const struct pv_info xen_info __initconst
= {
1063 .shared_kernel_pmd
= 0,
1065 #ifdef CONFIG_X86_64
1066 .extra_user_64bit_cs
= FLAT_USER_CS64
,
1071 static const struct pv_init_ops xen_init_ops __initconst
= {
1075 static const struct pv_cpu_ops xen_cpu_ops __initconst
= {
1078 .set_debugreg
= xen_set_debugreg
,
1079 .get_debugreg
= xen_get_debugreg
,
1081 .read_cr0
= xen_read_cr0
,
1082 .write_cr0
= xen_write_cr0
,
1084 .read_cr4
= native_read_cr4
,
1085 .write_cr4
= xen_write_cr4
,
1087 #ifdef CONFIG_X86_64
1088 .read_cr8
= xen_read_cr8
,
1089 .write_cr8
= xen_write_cr8
,
1092 .wbinvd
= native_wbinvd
,
1094 .read_msr
= xen_read_msr
,
1095 .write_msr
= xen_write_msr
,
1097 .read_msr_safe
= xen_read_msr_safe
,
1098 .write_msr_safe
= xen_write_msr_safe
,
1100 .read_pmc
= xen_read_pmc
,
1103 #ifdef CONFIG_X86_64
1104 .usergs_sysret64
= xen_sysret64
,
1107 .load_tr_desc
= paravirt_nop
,
1108 .set_ldt
= xen_set_ldt
,
1109 .load_gdt
= xen_load_gdt
,
1110 .load_idt
= xen_load_idt
,
1111 .load_tls
= xen_load_tls
,
1112 #ifdef CONFIG_X86_64
1113 .load_gs_index
= xen_load_gs_index
,
1116 .alloc_ldt
= xen_alloc_ldt
,
1117 .free_ldt
= xen_free_ldt
,
1119 .store_idt
= native_store_idt
,
1120 .store_tr
= xen_store_tr
,
1122 .write_ldt_entry
= xen_write_ldt_entry
,
1123 .write_gdt_entry
= xen_write_gdt_entry
,
1124 .write_idt_entry
= xen_write_idt_entry
,
1125 .load_sp0
= xen_load_sp0
,
1127 .set_iopl_mask
= xen_set_iopl_mask
,
1128 .io_delay
= xen_io_delay
,
1130 /* Xen takes care of %gs when switching to usermode for us */
1131 .swapgs
= paravirt_nop
,
1133 .start_context_switch
= paravirt_start_context_switch
,
1134 .end_context_switch
= xen_end_context_switch
,
1137 static void xen_restart(char *msg
)
1139 xen_reboot(SHUTDOWN_reboot
);
1142 static void xen_machine_halt(void)
1144 xen_reboot(SHUTDOWN_poweroff
);
1147 static void xen_machine_power_off(void)
1151 xen_reboot(SHUTDOWN_poweroff
);
1154 static void xen_crash_shutdown(struct pt_regs
*regs
)
1156 xen_reboot(SHUTDOWN_crash
);
1159 static const struct machine_ops xen_machine_ops __initconst
= {
1160 .restart
= xen_restart
,
1161 .halt
= xen_machine_halt
,
1162 .power_off
= xen_machine_power_off
,
1163 .shutdown
= xen_machine_halt
,
1164 .crash_shutdown
= xen_crash_shutdown
,
1165 .emergency_restart
= xen_emergency_restart
,
1168 static unsigned char xen_get_nmi_reason(void)
1170 unsigned char reason
= 0;
1172 /* Construct a value which looks like it came from port 0x61. */
1173 if (test_bit(_XEN_NMIREASON_io_error
,
1174 &HYPERVISOR_shared_info
->arch
.nmi_reason
))
1175 reason
|= NMI_REASON_IOCHK
;
1176 if (test_bit(_XEN_NMIREASON_pci_serr
,
1177 &HYPERVISOR_shared_info
->arch
.nmi_reason
))
1178 reason
|= NMI_REASON_SERR
;
1183 static void __init
xen_boot_params_init_edd(void)
1185 #if IS_ENABLED(CONFIG_EDD)
1186 struct xen_platform_op op
;
1187 struct edd_info
*edd_info
;
1192 edd_info
= boot_params
.eddbuf
;
1193 mbr_signature
= boot_params
.edd_mbr_sig_buffer
;
1195 op
.cmd
= XENPF_firmware_info
;
1197 op
.u
.firmware_info
.type
= XEN_FW_DISK_INFO
;
1198 for (nr
= 0; nr
< EDDMAXNR
; nr
++) {
1199 struct edd_info
*info
= edd_info
+ nr
;
1201 op
.u
.firmware_info
.index
= nr
;
1202 info
->params
.length
= sizeof(info
->params
);
1203 set_xen_guest_handle(op
.u
.firmware_info
.u
.disk_info
.edd_params
,
1205 ret
= HYPERVISOR_platform_op(&op
);
1209 #define C(x) info->x = op.u.firmware_info.u.disk_info.x
1212 C(interface_support
);
1213 C(legacy_max_cylinder
);
1215 C(legacy_sectors_per_track
);
1218 boot_params
.eddbuf_entries
= nr
;
1220 op
.u
.firmware_info
.type
= XEN_FW_DISK_MBR_SIGNATURE
;
1221 for (nr
= 0; nr
< EDD_MBR_SIG_MAX
; nr
++) {
1222 op
.u
.firmware_info
.index
= nr
;
1223 ret
= HYPERVISOR_platform_op(&op
);
1226 mbr_signature
[nr
] = op
.u
.firmware_info
.u
.disk_mbr_signature
.mbr_signature
;
1228 boot_params
.edd_mbr_sig_buf_entries
= nr
;
1233 * Set up the GDT and segment registers for -fstack-protector. Until
1234 * we do this, we have to be careful not to call any stack-protected
1235 * function, which is most of the kernel.
1237 static void xen_setup_gdt(int cpu
)
1239 pv_cpu_ops
.write_gdt_entry
= xen_write_gdt_entry_boot
;
1240 pv_cpu_ops
.load_gdt
= xen_load_gdt_boot
;
1242 setup_stack_canary_segment(0);
1243 switch_to_new_gdt(0);
1245 pv_cpu_ops
.write_gdt_entry
= xen_write_gdt_entry
;
1246 pv_cpu_ops
.load_gdt
= xen_load_gdt
;
1249 static void __init
xen_dom0_set_legacy_features(void)
1251 x86_platform
.legacy
.rtc
= 1;
1254 /* First C function to be called on Xen boot */
1255 asmlinkage __visible
void __init
xen_start_kernel(void)
1257 struct physdev_set_iopl set_iopl
;
1258 unsigned long initrd_start
= 0;
1261 if (!xen_start_info
)
1264 xen_domain_type
= XEN_PV_DOMAIN
;
1266 xen_setup_features();
1268 xen_setup_machphys_mapping();
1270 /* Install Xen paravirt ops */
1272 pv_init_ops
= xen_init_ops
;
1273 pv_cpu_ops
= xen_cpu_ops
;
1275 x86_platform
.get_nmi_reason
= xen_get_nmi_reason
;
1277 x86_init
.resources
.memory_setup
= xen_memory_setup
;
1278 x86_init
.oem
.arch_setup
= xen_arch_setup
;
1279 x86_init
.oem
.banner
= xen_banner
;
1282 * Set up some pagetable state before starting to set any ptes.
1287 /* Prevent unwanted bits from being set in PTEs. */
1288 __supported_pte_mask
&= ~_PAGE_GLOBAL
;
1291 * Prevent page tables from being allocated in highmem, even
1292 * if CONFIG_HIGHPTE is enabled.
1294 __userpte_alloc_gfp
&= ~__GFP_HIGHMEM
;
1296 /* Work out if we support NX */
1300 xen_build_dynamic_phys_to_machine();
1303 * Set up kernel GDT and segment registers, mainly so that
1304 * -fstack-protector code can be executed.
1309 xen_init_capabilities();
1311 #ifdef CONFIG_X86_LOCAL_APIC
1313 * set up the basic apic ops.
1318 if (xen_feature(XENFEAT_mmu_pt_update_preserve_ad
)) {
1319 pv_mmu_ops
.ptep_modify_prot_start
= xen_ptep_modify_prot_start
;
1320 pv_mmu_ops
.ptep_modify_prot_commit
= xen_ptep_modify_prot_commit
;
1323 machine_ops
= xen_machine_ops
;
1326 * The only reliable way to retain the initial address of the
1327 * percpu gdt_page is to remember it here, so we can go and
1328 * mark it RW later, when the initial percpu area is freed.
1330 xen_initial_gdt
= &per_cpu(gdt_page
, 0);
1334 #ifdef CONFIG_ACPI_NUMA
1336 * The pages we from Xen are not related to machine pages, so
1337 * any NUMA information the kernel tries to get from ACPI will
1338 * be meaningless. Prevent it from trying.
1342 /* Don't do the full vcpu_info placement stuff until we have a
1343 possible map and a non-dummy shared_info. */
1344 per_cpu(xen_vcpu
, 0) = &HYPERVISOR_shared_info
->vcpu_info
[0];
1346 WARN_ON(xen_cpuhp_setup(xen_cpu_up_prepare_pv
, xen_cpu_dead_pv
));
1348 local_irq_disable();
1349 early_boot_irqs_disabled
= true;
1351 xen_raw_console_write("mapping kernel into physical memory\n");
1352 xen_setup_kernel_pagetable((pgd_t
*)xen_start_info
->pt_base
,
1353 xen_start_info
->nr_pages
);
1354 xen_reserve_special_pages();
1356 /* keep using Xen gdt for now; no urgent need to change it */
1358 #ifdef CONFIG_X86_32
1359 pv_info
.kernel_rpl
= 1;
1360 if (xen_feature(XENFEAT_supervisor_mode_kernel
))
1361 pv_info
.kernel_rpl
= 0;
1363 pv_info
.kernel_rpl
= 0;
1365 /* set the limit of our address space */
1369 * We used to do this in xen_arch_setup, but that is too late
1370 * on AMD were early_cpu_init (run before ->arch_setup()) calls
1371 * early_amd_init which pokes 0xcf8 port.
1374 rc
= HYPERVISOR_physdev_op(PHYSDEVOP_set_iopl
, &set_iopl
);
1376 xen_raw_printk("physdev_op failed %d\n", rc
);
1378 #ifdef CONFIG_X86_32
1379 /* set up basic CPUID stuff */
1380 cpu_detect(&new_cpu_data
);
1381 set_cpu_cap(&new_cpu_data
, X86_FEATURE_FPU
);
1382 new_cpu_data
.x86_capability
[CPUID_1_EDX
] = cpuid_edx(1);
1385 if (xen_start_info
->mod_start
) {
1386 if (xen_start_info
->flags
& SIF_MOD_START_PFN
)
1387 initrd_start
= PFN_PHYS(xen_start_info
->mod_start
);
1389 initrd_start
= __pa(xen_start_info
->mod_start
);
1392 /* Poke various useful things into boot_params */
1393 boot_params
.hdr
.type_of_loader
= (9 << 4) | 0;
1394 boot_params
.hdr
.ramdisk_image
= initrd_start
;
1395 boot_params
.hdr
.ramdisk_size
= xen_start_info
->mod_len
;
1396 boot_params
.hdr
.cmd_line_ptr
= __pa(xen_start_info
->cmd_line
);
1397 boot_params
.hdr
.hardware_subarch
= X86_SUBARCH_XEN
;
1399 if (!xen_initial_domain()) {
1400 add_preferred_console("xenboot", 0, NULL
);
1401 add_preferred_console("tty", 0, NULL
);
1402 add_preferred_console("hvc", 0, NULL
);
1404 x86_init
.pci
.arch_init
= pci_xen_init
;
1406 const struct dom0_vga_console_info
*info
=
1407 (void *)((char *)xen_start_info
+
1408 xen_start_info
->console
.dom0
.info_off
);
1409 struct xen_platform_op op
= {
1410 .cmd
= XENPF_firmware_info
,
1411 .interface_version
= XENPF_INTERFACE_VERSION
,
1412 .u
.firmware_info
.type
= XEN_FW_KBD_SHIFT_FLAGS
,
1415 x86_platform
.set_legacy_features
=
1416 xen_dom0_set_legacy_features
;
1417 xen_init_vga(info
, xen_start_info
->console
.dom0
.info_size
);
1418 xen_start_info
->console
.domU
.mfn
= 0;
1419 xen_start_info
->console
.domU
.evtchn
= 0;
1421 if (HYPERVISOR_platform_op(&op
) == 0)
1422 boot_params
.kbd_status
= op
.u
.firmware_info
.u
.kbd_shift_flags
;
1424 /* Make sure ACS will be enabled */
1427 xen_acpi_sleep_register();
1429 /* Avoid searching for BIOS MP tables */
1430 x86_init
.mpparse
.find_smp_config
= x86_init_noop
;
1431 x86_init
.mpparse
.get_smp_config
= x86_init_uint_noop
;
1433 xen_boot_params_init_edd();
1436 /* PCI BIOS service won't work from a PV guest. */
1437 pci_probe
&= ~PCI_PROBE_BIOS
;
1439 xen_raw_console_write("about to get started...\n");
1441 /* Let's presume PV guests always boot on vCPU with id 0. */
1442 per_cpu(xen_vcpu_id
, 0) = 0;
1444 xen_setup_runstate_info(0);
1448 /* Start the world */
1449 #ifdef CONFIG_X86_32
1450 i386_start_kernel();
1452 cr4_init_shadow(); /* 32b kernel does this in i386_start_kernel() */
1453 x86_64_start_reservations((char *)__pa_symbol(&boot_params
));
1457 static int xen_cpu_up_prepare_pv(unsigned int cpu
)
1461 xen_setup_timer(cpu
);
1463 rc
= xen_smp_intr_init(cpu
);
1465 WARN(1, "xen_smp_intr_init() for CPU %d failed: %d\n",
1470 rc
= xen_smp_intr_init_pv(cpu
);
1472 WARN(1, "xen_smp_intr_init_pv() for CPU %d failed: %d\n",
1480 static int xen_cpu_dead_pv(unsigned int cpu
)
1482 xen_smp_intr_free(cpu
);
1483 xen_smp_intr_free_pv(cpu
);
1485 xen_teardown_timer(cpu
);
1490 static uint32_t __init
xen_platform_pv(void)
1492 if (xen_pv_domain())
1493 return xen_cpuid_base();
1498 const struct hypervisor_x86 x86_hyper_xen_pv
= {
1500 .detect
= xen_platform_pv
,
1501 .pin_vcpu
= xen_pin_vcpu
,
1503 EXPORT_SYMBOL(x86_hyper_xen_pv
);