1 // SPDX-License-Identifier: GPL-2.0
3 * Core of Xen paravirt_ops implementation.
5 * This file contains the xen_paravirt_ops structure itself, and the
7 * - privileged instructions
12 * Jeremy Fitzhardinge <jeremy@xensource.com>, XenSource Inc, 2007
15 #include <linux/cpu.h>
16 #include <linux/kernel.h>
17 #include <linux/init.h>
18 #include <linux/smp.h>
19 #include <linux/preempt.h>
20 #include <linux/hardirq.h>
21 #include <linux/percpu.h>
22 #include <linux/delay.h>
23 #include <linux/start_kernel.h>
24 #include <linux/sched.h>
25 #include <linux/kprobes.h>
26 #include <linux/bootmem.h>
27 #include <linux/export.h>
29 #include <linux/page-flags.h>
30 #include <linux/highmem.h>
31 #include <linux/console.h>
32 #include <linux/pci.h>
33 #include <linux/gfp.h>
34 #include <linux/memblock.h>
35 #include <linux/edd.h>
36 #include <linux/frame.h>
39 #include <xen/events.h>
40 #include <xen/interface/xen.h>
41 #include <xen/interface/version.h>
42 #include <xen/interface/physdev.h>
43 #include <xen/interface/vcpu.h>
44 #include <xen/interface/memory.h>
45 #include <xen/interface/nmi.h>
46 #include <xen/interface/xen-mca.h>
47 #include <xen/features.h>
49 #include <xen/hvc-console.h>
52 #include <asm/paravirt.h>
55 #include <asm/xen/pci.h>
56 #include <asm/xen/hypercall.h>
57 #include <asm/xen/hypervisor.h>
58 #include <asm/xen/cpuid.h>
59 #include <asm/fixmap.h>
60 #include <asm/processor.h>
61 #include <asm/proto.h>
62 #include <asm/msr-index.h>
63 #include <asm/traps.h>
64 #include <asm/setup.h>
66 #include <asm/pgalloc.h>
67 #include <asm/pgtable.h>
68 #include <asm/tlbflush.h>
69 #include <asm/reboot.h>
70 #include <asm/stackprotector.h>
71 #include <asm/hypervisor.h>
72 #include <asm/mach_traps.h>
73 #include <asm/mwait.h>
74 #include <asm/pci_x86.h>
78 #include <linux/acpi.h>
80 #include <acpi/pdc_intel.h>
81 #include <acpi/processor.h>
82 #include <xen/interface/platform.h>
88 #include "multicalls.h"
91 #include "../kernel/cpu/cpu.h" /* get_cpu_cap() */
93 void *xen_initial_gdt
;
95 static int xen_cpu_up_prepare_pv(unsigned int cpu
);
96 static int xen_cpu_dead_pv(unsigned int cpu
);
99 struct desc_struct desc
[3];
103 * Updating the 3 TLS descriptors in the GDT on every task switch is
104 * surprisingly expensive so we avoid updating them if they haven't
105 * changed. Since Xen writes different descriptors than the one
106 * passed in the update_descriptor hypercall we keep shadow copies to
109 static DEFINE_PER_CPU(struct tls_descs
, shadow_tls_desc
);
111 static void __init
xen_banner(void)
113 unsigned version
= HYPERVISOR_xen_version(XENVER_version
, NULL
);
114 struct xen_extraversion extra
;
115 HYPERVISOR_xen_version(XENVER_extraversion
, &extra
);
117 pr_info("Booting paravirtualized kernel on %s\n", pv_info
.name
);
118 printk(KERN_INFO
"Xen version: %d.%d%s%s\n",
119 version
>> 16, version
& 0xffff, extra
.extraversion
,
120 xen_feature(XENFEAT_mmu_pt_update_preserve_ad
) ? " (preserve-AD)" : "");
122 /* Check if running on Xen version (major, minor) or later */
124 xen_running_on_version_or_later(unsigned int major
, unsigned int minor
)
126 unsigned int version
;
131 version
= HYPERVISOR_xen_version(XENVER_version
, NULL
);
132 if ((((version
>> 16) == major
) && ((version
& 0xffff) >= minor
)) ||
133 ((version
>> 16) > major
))
138 static __read_mostly
unsigned int cpuid_leaf5_ecx_val
;
139 static __read_mostly
unsigned int cpuid_leaf5_edx_val
;
141 static void xen_cpuid(unsigned int *ax
, unsigned int *bx
,
142 unsigned int *cx
, unsigned int *dx
)
144 unsigned maskebx
= ~0;
147 * Mask out inconvenient features, to try and disable as many
148 * unsupported kernel subsystems as possible.
151 case CPUID_MWAIT_LEAF
:
152 /* Synthesize the values.. */
155 *cx
= cpuid_leaf5_ecx_val
;
156 *dx
= cpuid_leaf5_edx_val
;
160 /* Suppress extended topology stuff */
165 asm(XEN_EMULATE_PREFIX
"cpuid"
170 : "0" (*ax
), "2" (*cx
));
174 STACK_FRAME_NON_STANDARD(xen_cpuid
); /* XEN_EMULATE_PREFIX */
176 static bool __init
xen_check_mwait(void)
179 struct xen_platform_op op
= {
180 .cmd
= XENPF_set_processor_pminfo
,
181 .u
.set_pminfo
.id
= -1,
182 .u
.set_pminfo
.type
= XEN_PM_PDC
,
185 unsigned int ax
, bx
, cx
, dx
;
186 unsigned int mwait_mask
;
188 /* We need to determine whether it is OK to expose the MWAIT
189 * capability to the kernel to harvest deeper than C3 states from ACPI
190 * _CST using the processor_harvest_xen.c module. For this to work, we
191 * need to gather the MWAIT_LEAF values (which the cstate.c code
192 * checks against). The hypervisor won't expose the MWAIT flag because
193 * it would break backwards compatibility; so we will find out directly
194 * from the hardware and hypercall.
196 if (!xen_initial_domain())
200 * When running under platform earlier than Xen4.2, do not expose
201 * mwait, to avoid the risk of loading native acpi pad driver
203 if (!xen_running_on_version_or_later(4, 2))
209 native_cpuid(&ax
, &bx
, &cx
, &dx
);
211 mwait_mask
= (1 << (X86_FEATURE_EST
% 32)) |
212 (1 << (X86_FEATURE_MWAIT
% 32));
214 if ((cx
& mwait_mask
) != mwait_mask
)
217 /* We need to emulate the MWAIT_LEAF and for that we need both
218 * ecx and edx. The hypercall provides only partial information.
221 ax
= CPUID_MWAIT_LEAF
;
226 native_cpuid(&ax
, &bx
, &cx
, &dx
);
228 /* Ask the Hypervisor whether to clear ACPI_PDC_C_C2C3_FFH. If so,
229 * don't expose MWAIT_LEAF and let ACPI pick the IOPORT version of C3.
231 buf
[0] = ACPI_PDC_REVISION_ID
;
233 buf
[2] = (ACPI_PDC_C_CAPABILITY_SMP
| ACPI_PDC_EST_CAPABILITY_SWSMP
);
235 set_xen_guest_handle(op
.u
.set_pminfo
.pdc
, buf
);
237 if ((HYPERVISOR_platform_op(&op
) == 0) &&
238 (buf
[2] & (ACPI_PDC_C_C1_FFH
| ACPI_PDC_C_C2C3_FFH
))) {
239 cpuid_leaf5_ecx_val
= cx
;
240 cpuid_leaf5_edx_val
= dx
;
248 static bool __init
xen_check_xsave(void)
250 unsigned int cx
, xsave_mask
;
254 xsave_mask
= (1 << (X86_FEATURE_XSAVE
% 32)) |
255 (1 << (X86_FEATURE_OSXSAVE
% 32));
257 /* Xen will set CR4.OSXSAVE if supported and not disabled by force */
258 return (cx
& xsave_mask
) == xsave_mask
;
261 static void __init
xen_init_capabilities(void)
263 setup_force_cpu_cap(X86_FEATURE_XENPV
);
264 setup_clear_cpu_cap(X86_FEATURE_DCA
);
265 setup_clear_cpu_cap(X86_FEATURE_APERFMPERF
);
266 setup_clear_cpu_cap(X86_FEATURE_MTRR
);
267 setup_clear_cpu_cap(X86_FEATURE_ACC
);
268 setup_clear_cpu_cap(X86_FEATURE_X2APIC
);
269 setup_clear_cpu_cap(X86_FEATURE_SME
);
272 * Xen PV would need some work to support PCID: CR3 handling as well
273 * as xen_flush_tlb_others() would need updating.
275 setup_clear_cpu_cap(X86_FEATURE_PCID
);
277 if (!xen_initial_domain())
278 setup_clear_cpu_cap(X86_FEATURE_ACPI
);
280 if (xen_check_mwait())
281 setup_force_cpu_cap(X86_FEATURE_MWAIT
);
283 setup_clear_cpu_cap(X86_FEATURE_MWAIT
);
285 if (!xen_check_xsave()) {
286 setup_clear_cpu_cap(X86_FEATURE_XSAVE
);
287 setup_clear_cpu_cap(X86_FEATURE_OSXSAVE
);
291 static void xen_set_debugreg(int reg
, unsigned long val
)
293 HYPERVISOR_set_debugreg(reg
, val
);
296 static unsigned long xen_get_debugreg(int reg
)
298 return HYPERVISOR_get_debugreg(reg
);
301 static void xen_end_context_switch(struct task_struct
*next
)
304 paravirt_end_context_switch(next
);
307 static unsigned long xen_store_tr(void)
313 * Set the page permissions for a particular virtual address. If the
314 * address is a vmalloc mapping (or other non-linear mapping), then
315 * find the linear mapping of the page and also set its protections to
318 static void set_aliased_prot(void *v
, pgprot_t prot
)
327 ptep
= lookup_address((unsigned long)v
, &level
);
328 BUG_ON(ptep
== NULL
);
330 pfn
= pte_pfn(*ptep
);
331 page
= pfn_to_page(pfn
);
333 pte
= pfn_pte(pfn
, prot
);
336 * Careful: update_va_mapping() will fail if the virtual address
337 * we're poking isn't populated in the page tables. We don't
338 * need to worry about the direct map (that's always in the page
339 * tables), but we need to be careful about vmap space. In
340 * particular, the top level page table can lazily propagate
341 * entries between processes, so if we've switched mms since we
342 * vmapped the target in the first place, we might not have the
343 * top-level page table entry populated.
345 * We disable preemption because we want the same mm active when
346 * we probe the target and when we issue the hypercall. We'll
347 * have the same nominal mm, but if we're a kernel thread, lazy
348 * mm dropping could change our pgd.
350 * Out of an abundance of caution, this uses __get_user() to fault
351 * in the target address just in case there's some obscure case
352 * in which the target address isn't readable.
357 probe_kernel_read(&dummy
, v
, 1);
359 if (HYPERVISOR_update_va_mapping((unsigned long)v
, pte
, 0))
362 if (!PageHighMem(page
)) {
363 void *av
= __va(PFN_PHYS(pfn
));
366 if (HYPERVISOR_update_va_mapping((unsigned long)av
, pte
, 0))
374 static void xen_alloc_ldt(struct desc_struct
*ldt
, unsigned entries
)
376 const unsigned entries_per_page
= PAGE_SIZE
/ LDT_ENTRY_SIZE
;
380 * We need to mark the all aliases of the LDT pages RO. We
381 * don't need to call vm_flush_aliases(), though, since that's
382 * only responsible for flushing aliases out the TLBs, not the
383 * page tables, and Xen will flush the TLB for us if needed.
385 * To avoid confusing future readers: none of this is necessary
386 * to load the LDT. The hypervisor only checks this when the
387 * LDT is faulted in due to subsequent descriptor access.
390 for (i
= 0; i
< entries
; i
+= entries_per_page
)
391 set_aliased_prot(ldt
+ i
, PAGE_KERNEL_RO
);
394 static void xen_free_ldt(struct desc_struct
*ldt
, unsigned entries
)
396 const unsigned entries_per_page
= PAGE_SIZE
/ LDT_ENTRY_SIZE
;
399 for (i
= 0; i
< entries
; i
+= entries_per_page
)
400 set_aliased_prot(ldt
+ i
, PAGE_KERNEL
);
403 static void xen_set_ldt(const void *addr
, unsigned entries
)
405 struct mmuext_op
*op
;
406 struct multicall_space mcs
= xen_mc_entry(sizeof(*op
));
408 trace_xen_cpu_set_ldt(addr
, entries
);
411 op
->cmd
= MMUEXT_SET_LDT
;
412 op
->arg1
.linear_addr
= (unsigned long)addr
;
413 op
->arg2
.nr_ents
= entries
;
415 MULTI_mmuext_op(mcs
.mc
, op
, 1, NULL
, DOMID_SELF
);
417 xen_mc_issue(PARAVIRT_LAZY_CPU
);
420 static void xen_load_gdt(const struct desc_ptr
*dtr
)
422 unsigned long va
= dtr
->address
;
423 unsigned int size
= dtr
->size
+ 1;
424 unsigned pages
= DIV_ROUND_UP(size
, PAGE_SIZE
);
425 unsigned long frames
[pages
];
429 * A GDT can be up to 64k in size, which corresponds to 8192
430 * 8-byte entries, or 16 4k pages..
433 BUG_ON(size
> 65536);
434 BUG_ON(va
& ~PAGE_MASK
);
436 for (f
= 0; va
< dtr
->address
+ size
; va
+= PAGE_SIZE
, f
++) {
439 unsigned long pfn
, mfn
;
443 * The GDT is per-cpu and is in the percpu data area.
444 * That can be virtually mapped, so we need to do a
445 * page-walk to get the underlying MFN for the
446 * hypercall. The page can also be in the kernel's
447 * linear range, so we need to RO that mapping too.
449 ptep
= lookup_address(va
, &level
);
450 BUG_ON(ptep
== NULL
);
452 pfn
= pte_pfn(*ptep
);
453 mfn
= pfn_to_mfn(pfn
);
454 virt
= __va(PFN_PHYS(pfn
));
458 make_lowmem_page_readonly((void *)va
);
459 make_lowmem_page_readonly(virt
);
462 if (HYPERVISOR_set_gdt(frames
, size
/ sizeof(struct desc_struct
)))
467 * load_gdt for early boot, when the gdt is only mapped once
469 static void __init
xen_load_gdt_boot(const struct desc_ptr
*dtr
)
471 unsigned long va
= dtr
->address
;
472 unsigned int size
= dtr
->size
+ 1;
473 unsigned pages
= DIV_ROUND_UP(size
, PAGE_SIZE
);
474 unsigned long frames
[pages
];
478 * A GDT can be up to 64k in size, which corresponds to 8192
479 * 8-byte entries, or 16 4k pages..
482 BUG_ON(size
> 65536);
483 BUG_ON(va
& ~PAGE_MASK
);
485 for (f
= 0; va
< dtr
->address
+ size
; va
+= PAGE_SIZE
, f
++) {
487 unsigned long pfn
, mfn
;
489 pfn
= virt_to_pfn(va
);
490 mfn
= pfn_to_mfn(pfn
);
492 pte
= pfn_pte(pfn
, PAGE_KERNEL_RO
);
494 if (HYPERVISOR_update_va_mapping((unsigned long)va
, pte
, 0))
500 if (HYPERVISOR_set_gdt(frames
, size
/ sizeof(struct desc_struct
)))
504 static inline bool desc_equal(const struct desc_struct
*d1
,
505 const struct desc_struct
*d2
)
507 return !memcmp(d1
, d2
, sizeof(*d1
));
510 static void load_TLS_descriptor(struct thread_struct
*t
,
511 unsigned int cpu
, unsigned int i
)
513 struct desc_struct
*shadow
= &per_cpu(shadow_tls_desc
, cpu
).desc
[i
];
514 struct desc_struct
*gdt
;
516 struct multicall_space mc
;
518 if (desc_equal(shadow
, &t
->tls_array
[i
]))
521 *shadow
= t
->tls_array
[i
];
523 gdt
= get_cpu_gdt_rw(cpu
);
524 maddr
= arbitrary_virt_to_machine(&gdt
[GDT_ENTRY_TLS_MIN
+i
]);
525 mc
= __xen_mc_entry(0);
527 MULTI_update_descriptor(mc
.mc
, maddr
.maddr
, t
->tls_array
[i
]);
530 static void xen_load_tls(struct thread_struct
*t
, unsigned int cpu
)
533 * XXX sleazy hack: If we're being called in a lazy-cpu zone
534 * and lazy gs handling is enabled, it means we're in a
535 * context switch, and %gs has just been saved. This means we
536 * can zero it out to prevent faults on exit from the
537 * hypervisor if the next process has no %gs. Either way, it
538 * has been saved, and the new value will get loaded properly.
539 * This will go away as soon as Xen has been modified to not
540 * save/restore %gs for normal hypercalls.
542 * On x86_64, this hack is not used for %gs, because gs points
543 * to KERNEL_GS_BASE (and uses it for PDA references), so we
544 * must not zero %gs on x86_64
546 * For x86_64, we need to zero %fs, otherwise we may get an
547 * exception between the new %fs descriptor being loaded and
548 * %fs being effectively cleared at __switch_to().
550 if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_CPU
) {
560 load_TLS_descriptor(t
, cpu
, 0);
561 load_TLS_descriptor(t
, cpu
, 1);
562 load_TLS_descriptor(t
, cpu
, 2);
564 xen_mc_issue(PARAVIRT_LAZY_CPU
);
568 static void xen_load_gs_index(unsigned int idx
)
570 if (HYPERVISOR_set_segment_base(SEGBASE_GS_USER_SEL
, idx
))
575 static void xen_write_ldt_entry(struct desc_struct
*dt
, int entrynum
,
578 xmaddr_t mach_lp
= arbitrary_virt_to_machine(&dt
[entrynum
]);
579 u64 entry
= *(u64
*)ptr
;
581 trace_xen_cpu_write_ldt_entry(dt
, entrynum
, entry
);
586 if (HYPERVISOR_update_descriptor(mach_lp
.maddr
, entry
))
593 struct trap_array_entry
{
599 static struct trap_array_entry trap_array
[] = {
600 { debug
, xen_xendebug
, true },
601 { double_fault
, xen_double_fault
, true },
602 #ifdef CONFIG_X86_MCE
603 { machine_check
, xen_machine_check
, true },
605 { nmi
, xen_xennmi
, true },
606 { int3
, xen_int3
, false },
607 { overflow
, xen_overflow
, false },
608 #ifdef CONFIG_IA32_EMULATION
609 { entry_INT80_compat
, xen_entry_INT80_compat
, false },
611 { page_fault
, xen_page_fault
, false },
612 { divide_error
, xen_divide_error
, false },
613 { bounds
, xen_bounds
, false },
614 { invalid_op
, xen_invalid_op
, false },
615 { device_not_available
, xen_device_not_available
, false },
616 { coprocessor_segment_overrun
, xen_coprocessor_segment_overrun
, false },
617 { invalid_TSS
, xen_invalid_TSS
, false },
618 { segment_not_present
, xen_segment_not_present
, false },
619 { stack_segment
, xen_stack_segment
, false },
620 { general_protection
, xen_general_protection
, false },
621 { spurious_interrupt_bug
, xen_spurious_interrupt_bug
, false },
622 { coprocessor_error
, xen_coprocessor_error
, false },
623 { alignment_check
, xen_alignment_check
, false },
624 { simd_coprocessor_error
, xen_simd_coprocessor_error
, false },
627 static bool __ref
get_trap_addr(void **addr
, unsigned int ist
)
630 bool ist_okay
= false;
633 * Replace trap handler addresses by Xen specific ones.
634 * Check for known traps using IST and whitelist them.
635 * The debugger ones are the only ones we care about.
636 * Xen will handle faults like double_fault, * so we should never see
637 * them. Warn if there's an unexpected IST-using fault handler.
639 for (nr
= 0; nr
< ARRAY_SIZE(trap_array
); nr
++) {
640 struct trap_array_entry
*entry
= trap_array
+ nr
;
642 if (*addr
== entry
->orig
) {
644 ist_okay
= entry
->ist_okay
;
649 if (nr
== ARRAY_SIZE(trap_array
) &&
650 *addr
>= (void *)early_idt_handler_array
[0] &&
651 *addr
< (void *)early_idt_handler_array
[NUM_EXCEPTION_VECTORS
]) {
652 nr
= (*addr
- (void *)early_idt_handler_array
[0]) /
653 EARLY_IDT_HANDLER_SIZE
;
654 *addr
= (void *)xen_early_idt_handler_array
[nr
];
657 if (WARN_ON(ist
!= 0 && !ist_okay
))
664 static int cvt_gate_to_trap(int vector
, const gate_desc
*val
,
665 struct trap_info
*info
)
669 if (val
->bits
.type
!= GATE_TRAP
&& val
->bits
.type
!= GATE_INTERRUPT
)
672 info
->vector
= vector
;
674 addr
= gate_offset(val
);
676 if (!get_trap_addr((void **)&addr
, val
->bits
.ist
))
678 #endif /* CONFIG_X86_64 */
679 info
->address
= addr
;
681 info
->cs
= gate_segment(val
);
682 info
->flags
= val
->bits
.dpl
;
683 /* interrupt gates clear IF */
684 if (val
->bits
.type
== GATE_INTERRUPT
)
685 info
->flags
|= 1 << 2;
690 /* Locations of each CPU's IDT */
691 static DEFINE_PER_CPU(struct desc_ptr
, idt_desc
);
693 /* Set an IDT entry. If the entry is part of the current IDT, then
695 static void xen_write_idt_entry(gate_desc
*dt
, int entrynum
, const gate_desc
*g
)
697 unsigned long p
= (unsigned long)&dt
[entrynum
];
698 unsigned long start
, end
;
700 trace_xen_cpu_write_idt_entry(dt
, entrynum
, g
);
704 start
= __this_cpu_read(idt_desc
.address
);
705 end
= start
+ __this_cpu_read(idt_desc
.size
) + 1;
709 native_write_idt_entry(dt
, entrynum
, g
);
711 if (p
>= start
&& (p
+ 8) <= end
) {
712 struct trap_info info
[2];
716 if (cvt_gate_to_trap(entrynum
, g
, &info
[0]))
717 if (HYPERVISOR_set_trap_table(info
))
724 static void xen_convert_trap_info(const struct desc_ptr
*desc
,
725 struct trap_info
*traps
)
727 unsigned in
, out
, count
;
729 count
= (desc
->size
+1) / sizeof(gate_desc
);
732 for (in
= out
= 0; in
< count
; in
++) {
733 gate_desc
*entry
= (gate_desc
*)(desc
->address
) + in
;
735 if (cvt_gate_to_trap(in
, entry
, &traps
[out
]))
738 traps
[out
].address
= 0;
741 void xen_copy_trap_info(struct trap_info
*traps
)
743 const struct desc_ptr
*desc
= this_cpu_ptr(&idt_desc
);
745 xen_convert_trap_info(desc
, traps
);
748 /* Load a new IDT into Xen. In principle this can be per-CPU, so we
749 hold a spinlock to protect the static traps[] array (static because
750 it avoids allocation, and saves stack space). */
751 static void xen_load_idt(const struct desc_ptr
*desc
)
753 static DEFINE_SPINLOCK(lock
);
754 static struct trap_info traps
[257];
756 trace_xen_cpu_load_idt(desc
);
760 memcpy(this_cpu_ptr(&idt_desc
), desc
, sizeof(idt_desc
));
762 xen_convert_trap_info(desc
, traps
);
765 if (HYPERVISOR_set_trap_table(traps
))
771 /* Write a GDT descriptor entry. Ignore LDT descriptors, since
772 they're handled differently. */
773 static void xen_write_gdt_entry(struct desc_struct
*dt
, int entry
,
774 const void *desc
, int type
)
776 trace_xen_cpu_write_gdt_entry(dt
, entry
, desc
, type
);
787 xmaddr_t maddr
= arbitrary_virt_to_machine(&dt
[entry
]);
790 if (HYPERVISOR_update_descriptor(maddr
.maddr
, *(u64
*)desc
))
800 * Version of write_gdt_entry for use at early boot-time needed to
801 * update an entry as simply as possible.
803 static void __init
xen_write_gdt_entry_boot(struct desc_struct
*dt
, int entry
,
804 const void *desc
, int type
)
806 trace_xen_cpu_write_gdt_entry(dt
, entry
, desc
, type
);
815 xmaddr_t maddr
= virt_to_machine(&dt
[entry
]);
817 if (HYPERVISOR_update_descriptor(maddr
.maddr
, *(u64
*)desc
))
818 dt
[entry
] = *(struct desc_struct
*)desc
;
824 static void xen_load_sp0(unsigned long sp0
)
826 struct multicall_space mcs
;
828 mcs
= xen_mc_entry(0);
829 MULTI_stack_switch(mcs
.mc
, __KERNEL_DS
, sp0
);
830 xen_mc_issue(PARAVIRT_LAZY_CPU
);
831 this_cpu_write(cpu_tss_rw
.x86_tss
.sp0
, sp0
);
834 void xen_set_iopl_mask(unsigned mask
)
836 struct physdev_set_iopl set_iopl
;
838 /* Force the change at ring 0. */
839 set_iopl
.iopl
= (mask
== 0) ? 1 : (mask
>> 12) & 3;
840 HYPERVISOR_physdev_op(PHYSDEVOP_set_iopl
, &set_iopl
);
843 static void xen_io_delay(void)
847 static DEFINE_PER_CPU(unsigned long, xen_cr0_value
);
849 static unsigned long xen_read_cr0(void)
851 unsigned long cr0
= this_cpu_read(xen_cr0_value
);
853 if (unlikely(cr0
== 0)) {
854 cr0
= native_read_cr0();
855 this_cpu_write(xen_cr0_value
, cr0
);
861 static void xen_write_cr0(unsigned long cr0
)
863 struct multicall_space mcs
;
865 this_cpu_write(xen_cr0_value
, cr0
);
867 /* Only pay attention to cr0.TS; everything else is
869 mcs
= xen_mc_entry(0);
871 MULTI_fpu_taskswitch(mcs
.mc
, (cr0
& X86_CR0_TS
) != 0);
873 xen_mc_issue(PARAVIRT_LAZY_CPU
);
876 static void xen_write_cr4(unsigned long cr4
)
878 cr4
&= ~(X86_CR4_PGE
| X86_CR4_PSE
| X86_CR4_PCE
);
880 native_write_cr4(cr4
);
883 static inline unsigned long xen_read_cr8(void)
887 static inline void xen_write_cr8(unsigned long val
)
893 static u64
xen_read_msr_safe(unsigned int msr
, int *err
)
897 if (pmu_msr_read(msr
, &val
, err
))
900 val
= native_read_msr_safe(msr
, err
);
902 case MSR_IA32_APICBASE
:
903 val
&= ~X2APIC_ENABLE
;
909 static int xen_write_msr_safe(unsigned int msr
, unsigned low
, unsigned high
)
921 case MSR_FS_BASE
: which
= SEGBASE_FS
; goto set
;
922 case MSR_KERNEL_GS_BASE
: which
= SEGBASE_GS_USER
; goto set
;
923 case MSR_GS_BASE
: which
= SEGBASE_GS_KERNEL
; goto set
;
926 base
= ((u64
)high
<< 32) | low
;
927 if (HYPERVISOR_set_segment_base(which
, base
) != 0)
935 case MSR_SYSCALL_MASK
:
936 case MSR_IA32_SYSENTER_CS
:
937 case MSR_IA32_SYSENTER_ESP
:
938 case MSR_IA32_SYSENTER_EIP
:
939 /* Fast syscall setup is all done in hypercalls, so
940 these are all ignored. Stub them out here to stop
941 Xen console noise. */
945 if (!pmu_msr_write(msr
, low
, high
, &ret
))
946 ret
= native_write_msr_safe(msr
, low
, high
);
952 static u64
xen_read_msr(unsigned int msr
)
955 * This will silently swallow a #GP from RDMSR. It may be worth
960 return xen_read_msr_safe(msr
, &err
);
963 static void xen_write_msr(unsigned int msr
, unsigned low
, unsigned high
)
966 * This will silently swallow a #GP from WRMSR. It may be worth
969 xen_write_msr_safe(msr
, low
, high
);
972 void xen_setup_shared_info(void)
974 set_fixmap(FIX_PARAVIRT_BOOTMAP
, xen_start_info
->shared_info
);
976 HYPERVISOR_shared_info
=
977 (struct shared_info
*)fix_to_virt(FIX_PARAVIRT_BOOTMAP
);
979 xen_setup_mfn_list_list();
981 if (system_state
== SYSTEM_BOOTING
) {
984 * In UP this is as good a place as any to set up shared info.
985 * Limit this to boot only, at restore vcpu setup is done via
986 * xen_vcpu_restore().
988 xen_setup_vcpu_info_placement();
991 * Now that shared info is set up we can start using routines
992 * that point to pvclock area.
998 /* This is called once we have the cpu_possible_mask */
999 void __ref
xen_setup_vcpu_info_placement(void)
1003 for_each_possible_cpu(cpu
) {
1004 /* Set up direct vCPU id mapping for PV guests. */
1005 per_cpu(xen_vcpu_id
, cpu
) = cpu
;
1008 * xen_vcpu_setup(cpu) can fail -- in which case it
1009 * falls back to the shared_info version for cpus
1010 * where xen_vcpu_nr(cpu) < MAX_VIRT_CPUS.
1012 * xen_cpu_up_prepare_pv() handles the rest by failing
1015 (void) xen_vcpu_setup(cpu
);
1019 * xen_vcpu_setup managed to place the vcpu_info within the
1020 * percpu area for all cpus, so make use of it.
1022 if (xen_have_vcpu_info_placement
) {
1023 pv_irq_ops
.save_fl
= __PV_IS_CALLEE_SAVE(xen_save_fl_direct
);
1024 pv_irq_ops
.restore_fl
= __PV_IS_CALLEE_SAVE(xen_restore_fl_direct
);
1025 pv_irq_ops
.irq_disable
= __PV_IS_CALLEE_SAVE(xen_irq_disable_direct
);
1026 pv_irq_ops
.irq_enable
= __PV_IS_CALLEE_SAVE(xen_irq_enable_direct
);
1027 pv_mmu_ops
.read_cr2
= xen_read_cr2_direct
;
1031 static const struct pv_info xen_info __initconst
= {
1032 .shared_kernel_pmd
= 0,
1034 #ifdef CONFIG_X86_64
1035 .extra_user_64bit_cs
= FLAT_USER_CS64
,
1040 static const struct pv_cpu_ops xen_cpu_ops __initconst
= {
1043 .set_debugreg
= xen_set_debugreg
,
1044 .get_debugreg
= xen_get_debugreg
,
1046 .read_cr0
= xen_read_cr0
,
1047 .write_cr0
= xen_write_cr0
,
1049 .write_cr4
= xen_write_cr4
,
1051 #ifdef CONFIG_X86_64
1052 .read_cr8
= xen_read_cr8
,
1053 .write_cr8
= xen_write_cr8
,
1056 .wbinvd
= native_wbinvd
,
1058 .read_msr
= xen_read_msr
,
1059 .write_msr
= xen_write_msr
,
1061 .read_msr_safe
= xen_read_msr_safe
,
1062 .write_msr_safe
= xen_write_msr_safe
,
1064 .read_pmc
= xen_read_pmc
,
1067 #ifdef CONFIG_X86_64
1068 .usergs_sysret64
= xen_sysret64
,
1071 .load_tr_desc
= paravirt_nop
,
1072 .set_ldt
= xen_set_ldt
,
1073 .load_gdt
= xen_load_gdt
,
1074 .load_idt
= xen_load_idt
,
1075 .load_tls
= xen_load_tls
,
1076 #ifdef CONFIG_X86_64
1077 .load_gs_index
= xen_load_gs_index
,
1080 .alloc_ldt
= xen_alloc_ldt
,
1081 .free_ldt
= xen_free_ldt
,
1083 .store_tr
= xen_store_tr
,
1085 .write_ldt_entry
= xen_write_ldt_entry
,
1086 .write_gdt_entry
= xen_write_gdt_entry
,
1087 .write_idt_entry
= xen_write_idt_entry
,
1088 .load_sp0
= xen_load_sp0
,
1090 .set_iopl_mask
= xen_set_iopl_mask
,
1091 .io_delay
= xen_io_delay
,
1093 /* Xen takes care of %gs when switching to usermode for us */
1094 .swapgs
= paravirt_nop
,
1096 .start_context_switch
= paravirt_start_context_switch
,
1097 .end_context_switch
= xen_end_context_switch
,
1100 static void xen_restart(char *msg
)
1102 xen_reboot(SHUTDOWN_reboot
);
1105 static void xen_machine_halt(void)
1107 xen_reboot(SHUTDOWN_poweroff
);
1110 static void xen_machine_power_off(void)
1114 xen_reboot(SHUTDOWN_poweroff
);
1117 static void xen_crash_shutdown(struct pt_regs
*regs
)
1119 xen_reboot(SHUTDOWN_crash
);
1122 static const struct machine_ops xen_machine_ops __initconst
= {
1123 .restart
= xen_restart
,
1124 .halt
= xen_machine_halt
,
1125 .power_off
= xen_machine_power_off
,
1126 .shutdown
= xen_machine_halt
,
1127 .crash_shutdown
= xen_crash_shutdown
,
1128 .emergency_restart
= xen_emergency_restart
,
1131 static unsigned char xen_get_nmi_reason(void)
1133 unsigned char reason
= 0;
1135 /* Construct a value which looks like it came from port 0x61. */
1136 if (test_bit(_XEN_NMIREASON_io_error
,
1137 &HYPERVISOR_shared_info
->arch
.nmi_reason
))
1138 reason
|= NMI_REASON_IOCHK
;
1139 if (test_bit(_XEN_NMIREASON_pci_serr
,
1140 &HYPERVISOR_shared_info
->arch
.nmi_reason
))
1141 reason
|= NMI_REASON_SERR
;
1146 static void __init
xen_boot_params_init_edd(void)
1148 #if IS_ENABLED(CONFIG_EDD)
1149 struct xen_platform_op op
;
1150 struct edd_info
*edd_info
;
1155 edd_info
= boot_params
.eddbuf
;
1156 mbr_signature
= boot_params
.edd_mbr_sig_buffer
;
1158 op
.cmd
= XENPF_firmware_info
;
1160 op
.u
.firmware_info
.type
= XEN_FW_DISK_INFO
;
1161 for (nr
= 0; nr
< EDDMAXNR
; nr
++) {
1162 struct edd_info
*info
= edd_info
+ nr
;
1164 op
.u
.firmware_info
.index
= nr
;
1165 info
->params
.length
= sizeof(info
->params
);
1166 set_xen_guest_handle(op
.u
.firmware_info
.u
.disk_info
.edd_params
,
1168 ret
= HYPERVISOR_platform_op(&op
);
1172 #define C(x) info->x = op.u.firmware_info.u.disk_info.x
1175 C(interface_support
);
1176 C(legacy_max_cylinder
);
1178 C(legacy_sectors_per_track
);
1181 boot_params
.eddbuf_entries
= nr
;
1183 op
.u
.firmware_info
.type
= XEN_FW_DISK_MBR_SIGNATURE
;
1184 for (nr
= 0; nr
< EDD_MBR_SIG_MAX
; nr
++) {
1185 op
.u
.firmware_info
.index
= nr
;
1186 ret
= HYPERVISOR_platform_op(&op
);
1189 mbr_signature
[nr
] = op
.u
.firmware_info
.u
.disk_mbr_signature
.mbr_signature
;
1191 boot_params
.edd_mbr_sig_buf_entries
= nr
;
1196 * Set up the GDT and segment registers for -fstack-protector. Until
1197 * we do this, we have to be careful not to call any stack-protected
1198 * function, which is most of the kernel.
1200 static void xen_setup_gdt(int cpu
)
1202 pv_cpu_ops
.write_gdt_entry
= xen_write_gdt_entry_boot
;
1203 pv_cpu_ops
.load_gdt
= xen_load_gdt_boot
;
1205 setup_stack_canary_segment(0);
1206 switch_to_new_gdt(0);
1208 pv_cpu_ops
.write_gdt_entry
= xen_write_gdt_entry
;
1209 pv_cpu_ops
.load_gdt
= xen_load_gdt
;
1212 static void __init
xen_dom0_set_legacy_features(void)
1214 x86_platform
.legacy
.rtc
= 1;
1217 /* First C function to be called on Xen boot */
1218 asmlinkage __visible
void __init
xen_start_kernel(void)
1220 struct physdev_set_iopl set_iopl
;
1221 unsigned long initrd_start
= 0;
1224 if (!xen_start_info
)
1227 xen_domain_type
= XEN_PV_DOMAIN
;
1229 xen_setup_features();
1231 /* Install Xen paravirt ops */
1233 pv_init_ops
.patch
= paravirt_patch_default
;
1234 pv_cpu_ops
= xen_cpu_ops
;
1238 * Setup xen_vcpu early because it is needed for
1239 * local_irq_disable(), irqs_disabled(), e.g. in printk().
1241 * Don't do the full vcpu_info placement stuff until we have
1242 * the cpu_possible_mask and a non-dummy shared_info.
1244 xen_vcpu_info_reset(0);
1246 x86_platform
.get_nmi_reason
= xen_get_nmi_reason
;
1248 x86_init
.resources
.memory_setup
= xen_memory_setup
;
1249 x86_init
.oem
.arch_setup
= xen_arch_setup
;
1250 x86_init
.oem
.banner
= xen_banner
;
1253 * Set up some pagetable state before starting to set any ptes.
1256 xen_setup_machphys_mapping();
1259 /* Prevent unwanted bits from being set in PTEs. */
1260 __supported_pte_mask
&= ~_PAGE_GLOBAL
;
1263 * Prevent page tables from being allocated in highmem, even
1264 * if CONFIG_HIGHPTE is enabled.
1266 __userpte_alloc_gfp
&= ~__GFP_HIGHMEM
;
1269 xen_build_dynamic_phys_to_machine();
1272 * Set up kernel GDT and segment registers, mainly so that
1273 * -fstack-protector code can be executed.
1277 /* Work out if we support NX */
1278 get_cpu_cap(&boot_cpu_data
);
1281 /* Let's presume PV guests always boot on vCPU with id 0. */
1282 per_cpu(xen_vcpu_id
, 0) = 0;
1284 idt_setup_early_handler();
1286 xen_init_capabilities();
1288 #ifdef CONFIG_X86_LOCAL_APIC
1290 * set up the basic apic ops.
1295 if (xen_feature(XENFEAT_mmu_pt_update_preserve_ad
)) {
1296 pv_mmu_ops
.ptep_modify_prot_start
= xen_ptep_modify_prot_start
;
1297 pv_mmu_ops
.ptep_modify_prot_commit
= xen_ptep_modify_prot_commit
;
1300 machine_ops
= xen_machine_ops
;
1303 * The only reliable way to retain the initial address of the
1304 * percpu gdt_page is to remember it here, so we can go and
1305 * mark it RW later, when the initial percpu area is freed.
1307 xen_initial_gdt
= &per_cpu(gdt_page
, 0);
1311 #ifdef CONFIG_ACPI_NUMA
1313 * The pages we from Xen are not related to machine pages, so
1314 * any NUMA information the kernel tries to get from ACPI will
1315 * be meaningless. Prevent it from trying.
1319 WARN_ON(xen_cpuhp_setup(xen_cpu_up_prepare_pv
, xen_cpu_dead_pv
));
1321 local_irq_disable();
1322 early_boot_irqs_disabled
= true;
1324 xen_raw_console_write("mapping kernel into physical memory\n");
1325 xen_setup_kernel_pagetable((pgd_t
*)xen_start_info
->pt_base
,
1326 xen_start_info
->nr_pages
);
1327 xen_reserve_special_pages();
1329 /* keep using Xen gdt for now; no urgent need to change it */
1331 #ifdef CONFIG_X86_32
1332 pv_info
.kernel_rpl
= 1;
1333 if (xen_feature(XENFEAT_supervisor_mode_kernel
))
1334 pv_info
.kernel_rpl
= 0;
1336 pv_info
.kernel_rpl
= 0;
1338 /* set the limit of our address space */
1342 * We used to do this in xen_arch_setup, but that is too late
1343 * on AMD were early_cpu_init (run before ->arch_setup()) calls
1344 * early_amd_init which pokes 0xcf8 port.
1347 rc
= HYPERVISOR_physdev_op(PHYSDEVOP_set_iopl
, &set_iopl
);
1349 xen_raw_printk("physdev_op failed %d\n", rc
);
1351 #ifdef CONFIG_X86_32
1352 /* set up basic CPUID stuff */
1353 cpu_detect(&new_cpu_data
);
1354 set_cpu_cap(&new_cpu_data
, X86_FEATURE_FPU
);
1355 new_cpu_data
.x86_capability
[CPUID_1_EDX
] = cpuid_edx(1);
1358 if (xen_start_info
->mod_start
) {
1359 if (xen_start_info
->flags
& SIF_MOD_START_PFN
)
1360 initrd_start
= PFN_PHYS(xen_start_info
->mod_start
);
1362 initrd_start
= __pa(xen_start_info
->mod_start
);
1365 /* Poke various useful things into boot_params */
1366 boot_params
.hdr
.type_of_loader
= (9 << 4) | 0;
1367 boot_params
.hdr
.ramdisk_image
= initrd_start
;
1368 boot_params
.hdr
.ramdisk_size
= xen_start_info
->mod_len
;
1369 boot_params
.hdr
.cmd_line_ptr
= __pa(xen_start_info
->cmd_line
);
1370 boot_params
.hdr
.hardware_subarch
= X86_SUBARCH_XEN
;
1372 if (!xen_initial_domain()) {
1373 add_preferred_console("xenboot", 0, NULL
);
1374 add_preferred_console("tty", 0, NULL
);
1375 add_preferred_console("hvc", 0, NULL
);
1377 x86_init
.pci
.arch_init
= pci_xen_init
;
1379 const struct dom0_vga_console_info
*info
=
1380 (void *)((char *)xen_start_info
+
1381 xen_start_info
->console
.dom0
.info_off
);
1382 struct xen_platform_op op
= {
1383 .cmd
= XENPF_firmware_info
,
1384 .interface_version
= XENPF_INTERFACE_VERSION
,
1385 .u
.firmware_info
.type
= XEN_FW_KBD_SHIFT_FLAGS
,
1388 x86_platform
.set_legacy_features
=
1389 xen_dom0_set_legacy_features
;
1390 xen_init_vga(info
, xen_start_info
->console
.dom0
.info_size
);
1391 xen_start_info
->console
.domU
.mfn
= 0;
1392 xen_start_info
->console
.domU
.evtchn
= 0;
1394 if (HYPERVISOR_platform_op(&op
) == 0)
1395 boot_params
.kbd_status
= op
.u
.firmware_info
.u
.kbd_shift_flags
;
1397 /* Make sure ACS will be enabled */
1400 xen_acpi_sleep_register();
1402 /* Avoid searching for BIOS MP tables */
1403 x86_init
.mpparse
.find_smp_config
= x86_init_noop
;
1404 x86_init
.mpparse
.get_smp_config
= x86_init_uint_noop
;
1406 xen_boot_params_init_edd();
1410 * Disable selecting "Firmware First mode" for correctable
1411 * memory errors, as this is the duty of the hypervisor to
1414 acpi_disable_cmcff
= 1;
1418 /* PCI BIOS service won't work from a PV guest. */
1419 pci_probe
&= ~PCI_PROBE_BIOS
;
1421 xen_raw_console_write("about to get started...\n");
1423 /* We need this for printk timestamps */
1424 xen_setup_runstate_info(0);
1428 /* Start the world */
1429 #ifdef CONFIG_X86_32
1430 i386_start_kernel();
1432 cr4_init_shadow(); /* 32b kernel does this in i386_start_kernel() */
1433 x86_64_start_reservations((char *)__pa_symbol(&boot_params
));
1437 static int xen_cpu_up_prepare_pv(unsigned int cpu
)
1441 if (per_cpu(xen_vcpu
, cpu
) == NULL
)
1444 xen_setup_timer(cpu
);
1446 rc
= xen_smp_intr_init(cpu
);
1448 WARN(1, "xen_smp_intr_init() for CPU %d failed: %d\n",
1453 rc
= xen_smp_intr_init_pv(cpu
);
1455 WARN(1, "xen_smp_intr_init_pv() for CPU %d failed: %d\n",
1463 static int xen_cpu_dead_pv(unsigned int cpu
)
1465 xen_smp_intr_free(cpu
);
1466 xen_smp_intr_free_pv(cpu
);
1468 xen_teardown_timer(cpu
);
1473 static uint32_t __init
xen_platform_pv(void)
1475 if (xen_pv_domain())
1476 return xen_cpuid_base();
1481 const __initconst
struct hypervisor_x86 x86_hyper_xen_pv
= {
1483 .detect
= xen_platform_pv
,
1484 .type
= X86_HYPER_XEN_PV
,
1485 .runtime
.pin_vcpu
= xen_pin_vcpu
,