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/memblock.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/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 #include "../kernel/cpu/cpu.h" /* get_cpu_cap() */
92 void *xen_initial_gdt
;
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
);
110 static void __init
xen_banner(void)
112 unsigned version
= HYPERVISOR_xen_version(XENVER_version
, NULL
);
113 struct xen_extraversion extra
;
114 HYPERVISOR_xen_version(XENVER_extraversion
, &extra
);
116 pr_info("Booting paravirtualized kernel on %s\n", pv_info
.name
);
117 printk(KERN_INFO
"Xen version: %d.%d%s%s\n",
118 version
>> 16, version
& 0xffff, extra
.extraversion
,
119 xen_feature(XENFEAT_mmu_pt_update_preserve_ad
) ? " (preserve-AD)" : "");
122 static void __init
xen_pv_init_platform(void)
124 populate_extra_pte(fix_to_virt(FIX_PARAVIRT_BOOTMAP
));
126 set_fixmap(FIX_PARAVIRT_BOOTMAP
, xen_start_info
->shared_info
);
127 HYPERVISOR_shared_info
= (void *)fix_to_virt(FIX_PARAVIRT_BOOTMAP
);
129 /* xen clock uses per-cpu vcpu_info, need to init it for boot cpu */
130 xen_vcpu_info_reset(0);
132 /* pvclock is in shared info area */
136 static void __init
xen_pv_guest_late_init(void)
139 /* Setup shared vcpu info for non-smp configurations */
140 xen_setup_vcpu_info_placement();
144 /* Check if running on Xen version (major, minor) or later */
146 xen_running_on_version_or_later(unsigned int major
, unsigned int minor
)
148 unsigned int version
;
153 version
= HYPERVISOR_xen_version(XENVER_version
, NULL
);
154 if ((((version
>> 16) == major
) && ((version
& 0xffff) >= minor
)) ||
155 ((version
>> 16) > major
))
160 static __read_mostly
unsigned int cpuid_leaf5_ecx_val
;
161 static __read_mostly
unsigned int cpuid_leaf5_edx_val
;
163 static void xen_cpuid(unsigned int *ax
, unsigned int *bx
,
164 unsigned int *cx
, unsigned int *dx
)
166 unsigned maskebx
= ~0;
169 * Mask out inconvenient features, to try and disable as many
170 * unsupported kernel subsystems as possible.
173 case CPUID_MWAIT_LEAF
:
174 /* Synthesize the values.. */
177 *cx
= cpuid_leaf5_ecx_val
;
178 *dx
= cpuid_leaf5_edx_val
;
182 /* Suppress extended topology stuff */
187 asm(XEN_EMULATE_PREFIX
"cpuid"
192 : "0" (*ax
), "2" (*cx
));
196 STACK_FRAME_NON_STANDARD(xen_cpuid
); /* XEN_EMULATE_PREFIX */
198 static bool __init
xen_check_mwait(void)
201 struct xen_platform_op op
= {
202 .cmd
= XENPF_set_processor_pminfo
,
203 .u
.set_pminfo
.id
= -1,
204 .u
.set_pminfo
.type
= XEN_PM_PDC
,
207 unsigned int ax
, bx
, cx
, dx
;
208 unsigned int mwait_mask
;
210 /* We need to determine whether it is OK to expose the MWAIT
211 * capability to the kernel to harvest deeper than C3 states from ACPI
212 * _CST using the processor_harvest_xen.c module. For this to work, we
213 * need to gather the MWAIT_LEAF values (which the cstate.c code
214 * checks against). The hypervisor won't expose the MWAIT flag because
215 * it would break backwards compatibility; so we will find out directly
216 * from the hardware and hypercall.
218 if (!xen_initial_domain())
222 * When running under platform earlier than Xen4.2, do not expose
223 * mwait, to avoid the risk of loading native acpi pad driver
225 if (!xen_running_on_version_or_later(4, 2))
231 native_cpuid(&ax
, &bx
, &cx
, &dx
);
233 mwait_mask
= (1 << (X86_FEATURE_EST
% 32)) |
234 (1 << (X86_FEATURE_MWAIT
% 32));
236 if ((cx
& mwait_mask
) != mwait_mask
)
239 /* We need to emulate the MWAIT_LEAF and for that we need both
240 * ecx and edx. The hypercall provides only partial information.
243 ax
= CPUID_MWAIT_LEAF
;
248 native_cpuid(&ax
, &bx
, &cx
, &dx
);
250 /* Ask the Hypervisor whether to clear ACPI_PDC_C_C2C3_FFH. If so,
251 * don't expose MWAIT_LEAF and let ACPI pick the IOPORT version of C3.
253 buf
[0] = ACPI_PDC_REVISION_ID
;
255 buf
[2] = (ACPI_PDC_C_CAPABILITY_SMP
| ACPI_PDC_EST_CAPABILITY_SWSMP
);
257 set_xen_guest_handle(op
.u
.set_pminfo
.pdc
, buf
);
259 if ((HYPERVISOR_platform_op(&op
) == 0) &&
260 (buf
[2] & (ACPI_PDC_C_C1_FFH
| ACPI_PDC_C_C2C3_FFH
))) {
261 cpuid_leaf5_ecx_val
= cx
;
262 cpuid_leaf5_edx_val
= dx
;
270 static bool __init
xen_check_xsave(void)
272 unsigned int cx
, xsave_mask
;
276 xsave_mask
= (1 << (X86_FEATURE_XSAVE
% 32)) |
277 (1 << (X86_FEATURE_OSXSAVE
% 32));
279 /* Xen will set CR4.OSXSAVE if supported and not disabled by force */
280 return (cx
& xsave_mask
) == xsave_mask
;
283 static void __init
xen_init_capabilities(void)
285 setup_force_cpu_cap(X86_FEATURE_XENPV
);
286 setup_clear_cpu_cap(X86_FEATURE_DCA
);
287 setup_clear_cpu_cap(X86_FEATURE_APERFMPERF
);
288 setup_clear_cpu_cap(X86_FEATURE_MTRR
);
289 setup_clear_cpu_cap(X86_FEATURE_ACC
);
290 setup_clear_cpu_cap(X86_FEATURE_X2APIC
);
291 setup_clear_cpu_cap(X86_FEATURE_SME
);
294 * Xen PV would need some work to support PCID: CR3 handling as well
295 * as xen_flush_tlb_others() would need updating.
297 setup_clear_cpu_cap(X86_FEATURE_PCID
);
299 if (!xen_initial_domain())
300 setup_clear_cpu_cap(X86_FEATURE_ACPI
);
302 if (xen_check_mwait())
303 setup_force_cpu_cap(X86_FEATURE_MWAIT
);
305 setup_clear_cpu_cap(X86_FEATURE_MWAIT
);
307 if (!xen_check_xsave()) {
308 setup_clear_cpu_cap(X86_FEATURE_XSAVE
);
309 setup_clear_cpu_cap(X86_FEATURE_OSXSAVE
);
313 static void xen_set_debugreg(int reg
, unsigned long val
)
315 HYPERVISOR_set_debugreg(reg
, val
);
318 static unsigned long xen_get_debugreg(int reg
)
320 return HYPERVISOR_get_debugreg(reg
);
323 static void xen_end_context_switch(struct task_struct
*next
)
326 paravirt_end_context_switch(next
);
329 static unsigned long xen_store_tr(void)
335 * Set the page permissions for a particular virtual address. If the
336 * address is a vmalloc mapping (or other non-linear mapping), then
337 * find the linear mapping of the page and also set its protections to
340 static void set_aliased_prot(void *v
, pgprot_t prot
)
349 ptep
= lookup_address((unsigned long)v
, &level
);
350 BUG_ON(ptep
== NULL
);
352 pfn
= pte_pfn(*ptep
);
353 page
= pfn_to_page(pfn
);
355 pte
= pfn_pte(pfn
, prot
);
358 * Careful: update_va_mapping() will fail if the virtual address
359 * we're poking isn't populated in the page tables. We don't
360 * need to worry about the direct map (that's always in the page
361 * tables), but we need to be careful about vmap space. In
362 * particular, the top level page table can lazily propagate
363 * entries between processes, so if we've switched mms since we
364 * vmapped the target in the first place, we might not have the
365 * top-level page table entry populated.
367 * We disable preemption because we want the same mm active when
368 * we probe the target and when we issue the hypercall. We'll
369 * have the same nominal mm, but if we're a kernel thread, lazy
370 * mm dropping could change our pgd.
372 * Out of an abundance of caution, this uses __get_user() to fault
373 * in the target address just in case there's some obscure case
374 * in which the target address isn't readable.
379 probe_kernel_read(&dummy
, v
, 1);
381 if (HYPERVISOR_update_va_mapping((unsigned long)v
, pte
, 0))
384 if (!PageHighMem(page
)) {
385 void *av
= __va(PFN_PHYS(pfn
));
388 if (HYPERVISOR_update_va_mapping((unsigned long)av
, pte
, 0))
396 static void xen_alloc_ldt(struct desc_struct
*ldt
, unsigned entries
)
398 const unsigned entries_per_page
= PAGE_SIZE
/ LDT_ENTRY_SIZE
;
402 * We need to mark the all aliases of the LDT pages RO. We
403 * don't need to call vm_flush_aliases(), though, since that's
404 * only responsible for flushing aliases out the TLBs, not the
405 * page tables, and Xen will flush the TLB for us if needed.
407 * To avoid confusing future readers: none of this is necessary
408 * to load the LDT. The hypervisor only checks this when the
409 * LDT is faulted in due to subsequent descriptor access.
412 for (i
= 0; i
< entries
; i
+= entries_per_page
)
413 set_aliased_prot(ldt
+ i
, PAGE_KERNEL_RO
);
416 static void xen_free_ldt(struct desc_struct
*ldt
, unsigned entries
)
418 const unsigned entries_per_page
= PAGE_SIZE
/ LDT_ENTRY_SIZE
;
421 for (i
= 0; i
< entries
; i
+= entries_per_page
)
422 set_aliased_prot(ldt
+ i
, PAGE_KERNEL
);
425 static void xen_set_ldt(const void *addr
, unsigned entries
)
427 struct mmuext_op
*op
;
428 struct multicall_space mcs
= xen_mc_entry(sizeof(*op
));
430 trace_xen_cpu_set_ldt(addr
, entries
);
433 op
->cmd
= MMUEXT_SET_LDT
;
434 op
->arg1
.linear_addr
= (unsigned long)addr
;
435 op
->arg2
.nr_ents
= entries
;
437 MULTI_mmuext_op(mcs
.mc
, op
, 1, NULL
, DOMID_SELF
);
439 xen_mc_issue(PARAVIRT_LAZY_CPU
);
442 static void xen_load_gdt(const struct desc_ptr
*dtr
)
444 unsigned long va
= dtr
->address
;
445 unsigned int size
= dtr
->size
+ 1;
446 unsigned long pfn
, mfn
;
451 /* @size should be at most GDT_SIZE which is smaller than PAGE_SIZE. */
452 BUG_ON(size
> PAGE_SIZE
);
453 BUG_ON(va
& ~PAGE_MASK
);
456 * The GDT is per-cpu and is in the percpu data area.
457 * That can be virtually mapped, so we need to do a
458 * page-walk to get the underlying MFN for the
459 * hypercall. The page can also be in the kernel's
460 * linear range, so we need to RO that mapping too.
462 ptep
= lookup_address(va
, &level
);
463 BUG_ON(ptep
== NULL
);
465 pfn
= pte_pfn(*ptep
);
466 mfn
= pfn_to_mfn(pfn
);
467 virt
= __va(PFN_PHYS(pfn
));
469 make_lowmem_page_readonly((void *)va
);
470 make_lowmem_page_readonly(virt
);
472 if (HYPERVISOR_set_gdt(&mfn
, size
/ sizeof(struct desc_struct
)))
477 * load_gdt for early boot, when the gdt is only mapped once
479 static void __init
xen_load_gdt_boot(const struct desc_ptr
*dtr
)
481 unsigned long va
= dtr
->address
;
482 unsigned int size
= dtr
->size
+ 1;
483 unsigned long pfn
, mfn
;
486 /* @size should be at most GDT_SIZE which is smaller than PAGE_SIZE. */
487 BUG_ON(size
> PAGE_SIZE
);
488 BUG_ON(va
& ~PAGE_MASK
);
490 pfn
= virt_to_pfn(va
);
491 mfn
= pfn_to_mfn(pfn
);
493 pte
= pfn_pte(pfn
, PAGE_KERNEL_RO
);
495 if (HYPERVISOR_update_va_mapping((unsigned long)va
, pte
, 0))
498 if (HYPERVISOR_set_gdt(&mfn
, size
/ sizeof(struct desc_struct
)))
502 static inline bool desc_equal(const struct desc_struct
*d1
,
503 const struct desc_struct
*d2
)
505 return !memcmp(d1
, d2
, sizeof(*d1
));
508 static void load_TLS_descriptor(struct thread_struct
*t
,
509 unsigned int cpu
, unsigned int i
)
511 struct desc_struct
*shadow
= &per_cpu(shadow_tls_desc
, cpu
).desc
[i
];
512 struct desc_struct
*gdt
;
514 struct multicall_space mc
;
516 if (desc_equal(shadow
, &t
->tls_array
[i
]))
519 *shadow
= t
->tls_array
[i
];
521 gdt
= get_cpu_gdt_rw(cpu
);
522 maddr
= arbitrary_virt_to_machine(&gdt
[GDT_ENTRY_TLS_MIN
+i
]);
523 mc
= __xen_mc_entry(0);
525 MULTI_update_descriptor(mc
.mc
, maddr
.maddr
, t
->tls_array
[i
]);
528 static void xen_load_tls(struct thread_struct
*t
, unsigned int cpu
)
531 * XXX sleazy hack: If we're being called in a lazy-cpu zone
532 * and lazy gs handling is enabled, it means we're in a
533 * context switch, and %gs has just been saved. This means we
534 * can zero it out to prevent faults on exit from the
535 * hypervisor if the next process has no %gs. Either way, it
536 * has been saved, and the new value will get loaded properly.
537 * This will go away as soon as Xen has been modified to not
538 * save/restore %gs for normal hypercalls.
540 * On x86_64, this hack is not used for %gs, because gs points
541 * to KERNEL_GS_BASE (and uses it for PDA references), so we
542 * must not zero %gs on x86_64
544 * For x86_64, we need to zero %fs, otherwise we may get an
545 * exception between the new %fs descriptor being loaded and
546 * %fs being effectively cleared at __switch_to().
548 if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_CPU
) {
558 load_TLS_descriptor(t
, cpu
, 0);
559 load_TLS_descriptor(t
, cpu
, 1);
560 load_TLS_descriptor(t
, cpu
, 2);
562 xen_mc_issue(PARAVIRT_LAZY_CPU
);
566 static void xen_load_gs_index(unsigned int idx
)
568 if (HYPERVISOR_set_segment_base(SEGBASE_GS_USER_SEL
, idx
))
573 static void xen_write_ldt_entry(struct desc_struct
*dt
, int entrynum
,
576 xmaddr_t mach_lp
= arbitrary_virt_to_machine(&dt
[entrynum
]);
577 u64 entry
= *(u64
*)ptr
;
579 trace_xen_cpu_write_ldt_entry(dt
, entrynum
, entry
);
584 if (HYPERVISOR_update_descriptor(mach_lp
.maddr
, entry
))
591 struct trap_array_entry
{
597 static struct trap_array_entry trap_array
[] = {
598 { debug
, xen_xendebug
, true },
599 { int3
, xen_xenint3
, true },
600 { double_fault
, xen_double_fault
, true },
601 #ifdef CONFIG_X86_MCE
602 { machine_check
, xen_machine_check
, true },
604 { nmi
, xen_xennmi
, true },
605 { overflow
, xen_overflow
, false },
606 #ifdef CONFIG_IA32_EMULATION
607 { entry_INT80_compat
, xen_entry_INT80_compat
, false },
609 { page_fault
, xen_page_fault
, false },
610 { divide_error
, xen_divide_error
, false },
611 { bounds
, xen_bounds
, false },
612 { invalid_op
, xen_invalid_op
, false },
613 { device_not_available
, xen_device_not_available
, false },
614 { coprocessor_segment_overrun
, xen_coprocessor_segment_overrun
, false },
615 { invalid_TSS
, xen_invalid_TSS
, false },
616 { segment_not_present
, xen_segment_not_present
, false },
617 { stack_segment
, xen_stack_segment
, false },
618 { general_protection
, xen_general_protection
, false },
619 { spurious_interrupt_bug
, xen_spurious_interrupt_bug
, false },
620 { coprocessor_error
, xen_coprocessor_error
, false },
621 { alignment_check
, xen_alignment_check
, false },
622 { simd_coprocessor_error
, xen_simd_coprocessor_error
, false },
625 static bool __ref
get_trap_addr(void **addr
, unsigned int ist
)
628 bool ist_okay
= false;
631 * Replace trap handler addresses by Xen specific ones.
632 * Check for known traps using IST and whitelist them.
633 * The debugger ones are the only ones we care about.
634 * Xen will handle faults like double_fault, * so we should never see
635 * them. Warn if there's an unexpected IST-using fault handler.
637 for (nr
= 0; nr
< ARRAY_SIZE(trap_array
); nr
++) {
638 struct trap_array_entry
*entry
= trap_array
+ nr
;
640 if (*addr
== entry
->orig
) {
642 ist_okay
= entry
->ist_okay
;
647 if (nr
== ARRAY_SIZE(trap_array
) &&
648 *addr
>= (void *)early_idt_handler_array
[0] &&
649 *addr
< (void *)early_idt_handler_array
[NUM_EXCEPTION_VECTORS
]) {
650 nr
= (*addr
- (void *)early_idt_handler_array
[0]) /
651 EARLY_IDT_HANDLER_SIZE
;
652 *addr
= (void *)xen_early_idt_handler_array
[nr
];
655 if (WARN_ON(ist
!= 0 && !ist_okay
))
662 static int cvt_gate_to_trap(int vector
, const gate_desc
*val
,
663 struct trap_info
*info
)
667 if (val
->bits
.type
!= GATE_TRAP
&& val
->bits
.type
!= GATE_INTERRUPT
)
670 info
->vector
= vector
;
672 addr
= gate_offset(val
);
674 if (!get_trap_addr((void **)&addr
, val
->bits
.ist
))
676 #endif /* CONFIG_X86_64 */
677 info
->address
= addr
;
679 info
->cs
= gate_segment(val
);
680 info
->flags
= val
->bits
.dpl
;
681 /* interrupt gates clear IF */
682 if (val
->bits
.type
== GATE_INTERRUPT
)
683 info
->flags
|= 1 << 2;
688 /* Locations of each CPU's IDT */
689 static DEFINE_PER_CPU(struct desc_ptr
, idt_desc
);
691 /* Set an IDT entry. If the entry is part of the current IDT, then
693 static void xen_write_idt_entry(gate_desc
*dt
, int entrynum
, const gate_desc
*g
)
695 unsigned long p
= (unsigned long)&dt
[entrynum
];
696 unsigned long start
, end
;
698 trace_xen_cpu_write_idt_entry(dt
, entrynum
, g
);
702 start
= __this_cpu_read(idt_desc
.address
);
703 end
= start
+ __this_cpu_read(idt_desc
.size
) + 1;
707 native_write_idt_entry(dt
, entrynum
, g
);
709 if (p
>= start
&& (p
+ 8) <= end
) {
710 struct trap_info info
[2];
714 if (cvt_gate_to_trap(entrynum
, g
, &info
[0]))
715 if (HYPERVISOR_set_trap_table(info
))
722 static void xen_convert_trap_info(const struct desc_ptr
*desc
,
723 struct trap_info
*traps
)
725 unsigned in
, out
, count
;
727 count
= (desc
->size
+1) / sizeof(gate_desc
);
730 for (in
= out
= 0; in
< count
; in
++) {
731 gate_desc
*entry
= (gate_desc
*)(desc
->address
) + in
;
733 if (cvt_gate_to_trap(in
, entry
, &traps
[out
]))
736 traps
[out
].address
= 0;
739 void xen_copy_trap_info(struct trap_info
*traps
)
741 const struct desc_ptr
*desc
= this_cpu_ptr(&idt_desc
);
743 xen_convert_trap_info(desc
, traps
);
746 /* Load a new IDT into Xen. In principle this can be per-CPU, so we
747 hold a spinlock to protect the static traps[] array (static because
748 it avoids allocation, and saves stack space). */
749 static void xen_load_idt(const struct desc_ptr
*desc
)
751 static DEFINE_SPINLOCK(lock
);
752 static struct trap_info traps
[257];
754 trace_xen_cpu_load_idt(desc
);
758 memcpy(this_cpu_ptr(&idt_desc
), desc
, sizeof(idt_desc
));
760 xen_convert_trap_info(desc
, traps
);
763 if (HYPERVISOR_set_trap_table(traps
))
769 /* Write a GDT descriptor entry. Ignore LDT descriptors, since
770 they're handled differently. */
771 static void xen_write_gdt_entry(struct desc_struct
*dt
, int entry
,
772 const void *desc
, int type
)
774 trace_xen_cpu_write_gdt_entry(dt
, entry
, desc
, type
);
785 xmaddr_t maddr
= arbitrary_virt_to_machine(&dt
[entry
]);
788 if (HYPERVISOR_update_descriptor(maddr
.maddr
, *(u64
*)desc
))
798 * Version of write_gdt_entry for use at early boot-time needed to
799 * update an entry as simply as possible.
801 static void __init
xen_write_gdt_entry_boot(struct desc_struct
*dt
, int entry
,
802 const void *desc
, int type
)
804 trace_xen_cpu_write_gdt_entry(dt
, entry
, desc
, type
);
813 xmaddr_t maddr
= virt_to_machine(&dt
[entry
]);
815 if (HYPERVISOR_update_descriptor(maddr
.maddr
, *(u64
*)desc
))
816 dt
[entry
] = *(struct desc_struct
*)desc
;
822 static void xen_load_sp0(unsigned long sp0
)
824 struct multicall_space mcs
;
826 mcs
= xen_mc_entry(0);
827 MULTI_stack_switch(mcs
.mc
, __KERNEL_DS
, sp0
);
828 xen_mc_issue(PARAVIRT_LAZY_CPU
);
829 this_cpu_write(cpu_tss_rw
.x86_tss
.sp0
, sp0
);
832 void xen_set_iopl_mask(unsigned mask
)
834 struct physdev_set_iopl set_iopl
;
836 /* Force the change at ring 0. */
837 set_iopl
.iopl
= (mask
== 0) ? 1 : (mask
>> 12) & 3;
838 HYPERVISOR_physdev_op(PHYSDEVOP_set_iopl
, &set_iopl
);
841 static void xen_io_delay(void)
845 static DEFINE_PER_CPU(unsigned long, xen_cr0_value
);
847 static unsigned long xen_read_cr0(void)
849 unsigned long cr0
= this_cpu_read(xen_cr0_value
);
851 if (unlikely(cr0
== 0)) {
852 cr0
= native_read_cr0();
853 this_cpu_write(xen_cr0_value
, cr0
);
859 static void xen_write_cr0(unsigned long cr0
)
861 struct multicall_space mcs
;
863 this_cpu_write(xen_cr0_value
, cr0
);
865 /* Only pay attention to cr0.TS; everything else is
867 mcs
= xen_mc_entry(0);
869 MULTI_fpu_taskswitch(mcs
.mc
, (cr0
& X86_CR0_TS
) != 0);
871 xen_mc_issue(PARAVIRT_LAZY_CPU
);
874 static void xen_write_cr4(unsigned long cr4
)
876 cr4
&= ~(X86_CR4_PGE
| X86_CR4_PSE
| X86_CR4_PCE
);
878 native_write_cr4(cr4
);
881 static inline unsigned long xen_read_cr8(void)
885 static inline void xen_write_cr8(unsigned long val
)
891 static u64
xen_read_msr_safe(unsigned int msr
, int *err
)
895 if (pmu_msr_read(msr
, &val
, err
))
898 val
= native_read_msr_safe(msr
, err
);
900 case MSR_IA32_APICBASE
:
901 val
&= ~X2APIC_ENABLE
;
907 static int xen_write_msr_safe(unsigned int msr
, unsigned low
, unsigned high
)
918 case MSR_FS_BASE
: which
= SEGBASE_FS
; goto set
;
919 case MSR_KERNEL_GS_BASE
: which
= SEGBASE_GS_USER
; goto set
;
920 case MSR_GS_BASE
: which
= SEGBASE_GS_KERNEL
; goto set
;
923 base
= ((u64
)high
<< 32) | low
;
924 if (HYPERVISOR_set_segment_base(which
, base
) != 0)
932 case MSR_SYSCALL_MASK
:
933 case MSR_IA32_SYSENTER_CS
:
934 case MSR_IA32_SYSENTER_ESP
:
935 case MSR_IA32_SYSENTER_EIP
:
936 /* Fast syscall setup is all done in hypercalls, so
937 these are all ignored. Stub them out here to stop
938 Xen console noise. */
942 if (!pmu_msr_write(msr
, low
, high
, &ret
))
943 ret
= native_write_msr_safe(msr
, low
, high
);
949 static u64
xen_read_msr(unsigned int msr
)
952 * This will silently swallow a #GP from RDMSR. It may be worth
957 return xen_read_msr_safe(msr
, &err
);
960 static void xen_write_msr(unsigned int msr
, unsigned low
, unsigned high
)
963 * This will silently swallow a #GP from WRMSR. It may be worth
966 xen_write_msr_safe(msr
, low
, high
);
969 /* This is called once we have the cpu_possible_mask */
970 void __init
xen_setup_vcpu_info_placement(void)
974 for_each_possible_cpu(cpu
) {
975 /* Set up direct vCPU id mapping for PV guests. */
976 per_cpu(xen_vcpu_id
, cpu
) = cpu
;
979 * xen_vcpu_setup(cpu) can fail -- in which case it
980 * falls back to the shared_info version for cpus
981 * where xen_vcpu_nr(cpu) < MAX_VIRT_CPUS.
983 * xen_cpu_up_prepare_pv() handles the rest by failing
986 (void) xen_vcpu_setup(cpu
);
990 * xen_vcpu_setup managed to place the vcpu_info within the
991 * percpu area for all cpus, so make use of it.
993 if (xen_have_vcpu_info_placement
) {
994 pv_ops
.irq
.save_fl
= __PV_IS_CALLEE_SAVE(xen_save_fl_direct
);
995 pv_ops
.irq
.restore_fl
=
996 __PV_IS_CALLEE_SAVE(xen_restore_fl_direct
);
997 pv_ops
.irq
.irq_disable
=
998 __PV_IS_CALLEE_SAVE(xen_irq_disable_direct
);
999 pv_ops
.irq
.irq_enable
=
1000 __PV_IS_CALLEE_SAVE(xen_irq_enable_direct
);
1001 pv_ops
.mmu
.read_cr2
= xen_read_cr2_direct
;
1005 static const struct pv_info xen_info __initconst
= {
1006 .shared_kernel_pmd
= 0,
1008 #ifdef CONFIG_X86_64
1009 .extra_user_64bit_cs
= FLAT_USER_CS64
,
1014 static const struct pv_cpu_ops xen_cpu_ops __initconst
= {
1017 .set_debugreg
= xen_set_debugreg
,
1018 .get_debugreg
= xen_get_debugreg
,
1020 .read_cr0
= xen_read_cr0
,
1021 .write_cr0
= xen_write_cr0
,
1023 .write_cr4
= xen_write_cr4
,
1025 #ifdef CONFIG_X86_64
1026 .read_cr8
= xen_read_cr8
,
1027 .write_cr8
= xen_write_cr8
,
1030 .wbinvd
= native_wbinvd
,
1032 .read_msr
= xen_read_msr
,
1033 .write_msr
= xen_write_msr
,
1035 .read_msr_safe
= xen_read_msr_safe
,
1036 .write_msr_safe
= xen_write_msr_safe
,
1038 .read_pmc
= xen_read_pmc
,
1041 #ifdef CONFIG_X86_64
1042 .usergs_sysret64
= xen_sysret64
,
1045 .load_tr_desc
= paravirt_nop
,
1046 .set_ldt
= xen_set_ldt
,
1047 .load_gdt
= xen_load_gdt
,
1048 .load_idt
= xen_load_idt
,
1049 .load_tls
= xen_load_tls
,
1050 #ifdef CONFIG_X86_64
1051 .load_gs_index
= xen_load_gs_index
,
1054 .alloc_ldt
= xen_alloc_ldt
,
1055 .free_ldt
= xen_free_ldt
,
1057 .store_tr
= xen_store_tr
,
1059 .write_ldt_entry
= xen_write_ldt_entry
,
1060 .write_gdt_entry
= xen_write_gdt_entry
,
1061 .write_idt_entry
= xen_write_idt_entry
,
1062 .load_sp0
= xen_load_sp0
,
1064 .set_iopl_mask
= xen_set_iopl_mask
,
1065 .io_delay
= xen_io_delay
,
1067 /* Xen takes care of %gs when switching to usermode for us */
1068 .swapgs
= paravirt_nop
,
1070 .start_context_switch
= paravirt_start_context_switch
,
1071 .end_context_switch
= xen_end_context_switch
,
1074 static void xen_restart(char *msg
)
1076 xen_reboot(SHUTDOWN_reboot
);
1079 static void xen_machine_halt(void)
1081 xen_reboot(SHUTDOWN_poweroff
);
1084 static void xen_machine_power_off(void)
1088 xen_reboot(SHUTDOWN_poweroff
);
1091 static void xen_crash_shutdown(struct pt_regs
*regs
)
1093 xen_reboot(SHUTDOWN_crash
);
1096 static const struct machine_ops xen_machine_ops __initconst
= {
1097 .restart
= xen_restart
,
1098 .halt
= xen_machine_halt
,
1099 .power_off
= xen_machine_power_off
,
1100 .shutdown
= xen_machine_halt
,
1101 .crash_shutdown
= xen_crash_shutdown
,
1102 .emergency_restart
= xen_emergency_restart
,
1105 static unsigned char xen_get_nmi_reason(void)
1107 unsigned char reason
= 0;
1109 /* Construct a value which looks like it came from port 0x61. */
1110 if (test_bit(_XEN_NMIREASON_io_error
,
1111 &HYPERVISOR_shared_info
->arch
.nmi_reason
))
1112 reason
|= NMI_REASON_IOCHK
;
1113 if (test_bit(_XEN_NMIREASON_pci_serr
,
1114 &HYPERVISOR_shared_info
->arch
.nmi_reason
))
1115 reason
|= NMI_REASON_SERR
;
1120 static void __init
xen_boot_params_init_edd(void)
1122 #if IS_ENABLED(CONFIG_EDD)
1123 struct xen_platform_op op
;
1124 struct edd_info
*edd_info
;
1129 edd_info
= boot_params
.eddbuf
;
1130 mbr_signature
= boot_params
.edd_mbr_sig_buffer
;
1132 op
.cmd
= XENPF_firmware_info
;
1134 op
.u
.firmware_info
.type
= XEN_FW_DISK_INFO
;
1135 for (nr
= 0; nr
< EDDMAXNR
; nr
++) {
1136 struct edd_info
*info
= edd_info
+ nr
;
1138 op
.u
.firmware_info
.index
= nr
;
1139 info
->params
.length
= sizeof(info
->params
);
1140 set_xen_guest_handle(op
.u
.firmware_info
.u
.disk_info
.edd_params
,
1142 ret
= HYPERVISOR_platform_op(&op
);
1146 #define C(x) info->x = op.u.firmware_info.u.disk_info.x
1149 C(interface_support
);
1150 C(legacy_max_cylinder
);
1152 C(legacy_sectors_per_track
);
1155 boot_params
.eddbuf_entries
= nr
;
1157 op
.u
.firmware_info
.type
= XEN_FW_DISK_MBR_SIGNATURE
;
1158 for (nr
= 0; nr
< EDD_MBR_SIG_MAX
; nr
++) {
1159 op
.u
.firmware_info
.index
= nr
;
1160 ret
= HYPERVISOR_platform_op(&op
);
1163 mbr_signature
[nr
] = op
.u
.firmware_info
.u
.disk_mbr_signature
.mbr_signature
;
1165 boot_params
.edd_mbr_sig_buf_entries
= nr
;
1170 * Set up the GDT and segment registers for -fstack-protector. Until
1171 * we do this, we have to be careful not to call any stack-protected
1172 * function, which is most of the kernel.
1174 static void __init
xen_setup_gdt(int cpu
)
1176 pv_ops
.cpu
.write_gdt_entry
= xen_write_gdt_entry_boot
;
1177 pv_ops
.cpu
.load_gdt
= xen_load_gdt_boot
;
1179 setup_stack_canary_segment(cpu
);
1180 switch_to_new_gdt(cpu
);
1182 pv_ops
.cpu
.write_gdt_entry
= xen_write_gdt_entry
;
1183 pv_ops
.cpu
.load_gdt
= xen_load_gdt
;
1186 static void __init
xen_dom0_set_legacy_features(void)
1188 x86_platform
.legacy
.rtc
= 1;
1191 /* First C function to be called on Xen boot */
1192 asmlinkage __visible
void __init
xen_start_kernel(void)
1194 struct physdev_set_iopl set_iopl
;
1195 unsigned long initrd_start
= 0;
1198 if (!xen_start_info
)
1201 xen_domain_type
= XEN_PV_DOMAIN
;
1202 xen_start_flags
= xen_start_info
->flags
;
1204 xen_setup_features();
1206 /* Install Xen paravirt ops */
1208 pv_ops
.init
.patch
= paravirt_patch_default
;
1209 pv_ops
.cpu
= xen_cpu_ops
;
1213 * Setup xen_vcpu early because it is needed for
1214 * local_irq_disable(), irqs_disabled(), e.g. in printk().
1216 * Don't do the full vcpu_info placement stuff until we have
1217 * the cpu_possible_mask and a non-dummy shared_info.
1219 xen_vcpu_info_reset(0);
1221 x86_platform
.get_nmi_reason
= xen_get_nmi_reason
;
1223 x86_init
.resources
.memory_setup
= xen_memory_setup
;
1224 x86_init
.irqs
.intr_mode_init
= x86_init_noop
;
1225 x86_init
.oem
.arch_setup
= xen_arch_setup
;
1226 x86_init
.oem
.banner
= xen_banner
;
1227 x86_init
.hyper
.init_platform
= xen_pv_init_platform
;
1228 x86_init
.hyper
.guest_late_init
= xen_pv_guest_late_init
;
1231 * Set up some pagetable state before starting to set any ptes.
1234 xen_setup_machphys_mapping();
1237 /* Prevent unwanted bits from being set in PTEs. */
1238 __supported_pte_mask
&= ~_PAGE_GLOBAL
;
1239 __default_kernel_pte_mask
&= ~_PAGE_GLOBAL
;
1242 * Prevent page tables from being allocated in highmem, even
1243 * if CONFIG_HIGHPTE is enabled.
1245 __userpte_alloc_gfp
&= ~__GFP_HIGHMEM
;
1248 xen_build_dynamic_phys_to_machine();
1251 * Set up kernel GDT and segment registers, mainly so that
1252 * -fstack-protector code can be executed.
1256 /* Work out if we support NX */
1257 get_cpu_cap(&boot_cpu_data
);
1260 /* Determine virtual and physical address sizes */
1261 get_cpu_address_sizes(&boot_cpu_data
);
1263 /* Let's presume PV guests always boot on vCPU with id 0. */
1264 per_cpu(xen_vcpu_id
, 0) = 0;
1266 idt_setup_early_handler();
1268 xen_init_capabilities();
1270 #ifdef CONFIG_X86_LOCAL_APIC
1272 * set up the basic apic ops.
1277 if (xen_feature(XENFEAT_mmu_pt_update_preserve_ad
)) {
1278 pv_ops
.mmu
.ptep_modify_prot_start
=
1279 xen_ptep_modify_prot_start
;
1280 pv_ops
.mmu
.ptep_modify_prot_commit
=
1281 xen_ptep_modify_prot_commit
;
1284 machine_ops
= xen_machine_ops
;
1287 * The only reliable way to retain the initial address of the
1288 * percpu gdt_page is to remember it here, so we can go and
1289 * mark it RW later, when the initial percpu area is freed.
1291 xen_initial_gdt
= &per_cpu(gdt_page
, 0);
1295 #ifdef CONFIG_ACPI_NUMA
1297 * The pages we from Xen are not related to machine pages, so
1298 * any NUMA information the kernel tries to get from ACPI will
1299 * be meaningless. Prevent it from trying.
1303 WARN_ON(xen_cpuhp_setup(xen_cpu_up_prepare_pv
, xen_cpu_dead_pv
));
1305 local_irq_disable();
1306 early_boot_irqs_disabled
= true;
1308 xen_raw_console_write("mapping kernel into physical memory\n");
1309 xen_setup_kernel_pagetable((pgd_t
*)xen_start_info
->pt_base
,
1310 xen_start_info
->nr_pages
);
1311 xen_reserve_special_pages();
1313 /* keep using Xen gdt for now; no urgent need to change it */
1315 #ifdef CONFIG_X86_32
1316 pv_info
.kernel_rpl
= 1;
1317 if (xen_feature(XENFEAT_supervisor_mode_kernel
))
1318 pv_info
.kernel_rpl
= 0;
1320 pv_info
.kernel_rpl
= 0;
1322 /* set the limit of our address space */
1326 * We used to do this in xen_arch_setup, but that is too late
1327 * on AMD were early_cpu_init (run before ->arch_setup()) calls
1328 * early_amd_init which pokes 0xcf8 port.
1331 rc
= HYPERVISOR_physdev_op(PHYSDEVOP_set_iopl
, &set_iopl
);
1333 xen_raw_printk("physdev_op failed %d\n", rc
);
1335 #ifdef CONFIG_X86_32
1336 /* set up basic CPUID stuff */
1337 cpu_detect(&new_cpu_data
);
1338 set_cpu_cap(&new_cpu_data
, X86_FEATURE_FPU
);
1339 new_cpu_data
.x86_capability
[CPUID_1_EDX
] = cpuid_edx(1);
1342 if (xen_start_info
->mod_start
) {
1343 if (xen_start_info
->flags
& SIF_MOD_START_PFN
)
1344 initrd_start
= PFN_PHYS(xen_start_info
->mod_start
);
1346 initrd_start
= __pa(xen_start_info
->mod_start
);
1349 /* Poke various useful things into boot_params */
1350 boot_params
.hdr
.type_of_loader
= (9 << 4) | 0;
1351 boot_params
.hdr
.ramdisk_image
= initrd_start
;
1352 boot_params
.hdr
.ramdisk_size
= xen_start_info
->mod_len
;
1353 boot_params
.hdr
.cmd_line_ptr
= __pa(xen_start_info
->cmd_line
);
1354 boot_params
.hdr
.hardware_subarch
= X86_SUBARCH_XEN
;
1356 if (!xen_initial_domain()) {
1357 add_preferred_console("xenboot", 0, NULL
);
1359 x86_init
.pci
.arch_init
= pci_xen_init
;
1361 const struct dom0_vga_console_info
*info
=
1362 (void *)((char *)xen_start_info
+
1363 xen_start_info
->console
.dom0
.info_off
);
1364 struct xen_platform_op op
= {
1365 .cmd
= XENPF_firmware_info
,
1366 .interface_version
= XENPF_INTERFACE_VERSION
,
1367 .u
.firmware_info
.type
= XEN_FW_KBD_SHIFT_FLAGS
,
1370 x86_platform
.set_legacy_features
=
1371 xen_dom0_set_legacy_features
;
1372 xen_init_vga(info
, xen_start_info
->console
.dom0
.info_size
);
1373 xen_start_info
->console
.domU
.mfn
= 0;
1374 xen_start_info
->console
.domU
.evtchn
= 0;
1376 if (HYPERVISOR_platform_op(&op
) == 0)
1377 boot_params
.kbd_status
= op
.u
.firmware_info
.u
.kbd_shift_flags
;
1379 /* Make sure ACS will be enabled */
1382 xen_acpi_sleep_register();
1384 /* Avoid searching for BIOS MP tables */
1385 x86_init
.mpparse
.find_smp_config
= x86_init_noop
;
1386 x86_init
.mpparse
.get_smp_config
= x86_init_uint_noop
;
1388 xen_boot_params_init_edd();
1391 if (!boot_params
.screen_info
.orig_video_isVGA
)
1392 add_preferred_console("tty", 0, NULL
);
1393 add_preferred_console("hvc", 0, NULL
);
1394 if (boot_params
.screen_info
.orig_video_isVGA
)
1395 add_preferred_console("tty", 0, NULL
);
1398 /* PCI BIOS service won't work from a PV guest. */
1399 pci_probe
&= ~PCI_PROBE_BIOS
;
1401 xen_raw_console_write("about to get started...\n");
1403 /* We need this for printk timestamps */
1404 xen_setup_runstate_info(0);
1406 xen_efi_init(&boot_params
);
1408 /* Start the world */
1409 #ifdef CONFIG_X86_32
1410 i386_start_kernel();
1412 cr4_init_shadow(); /* 32b kernel does this in i386_start_kernel() */
1413 x86_64_start_reservations((char *)__pa_symbol(&boot_params
));
1417 static int xen_cpu_up_prepare_pv(unsigned int cpu
)
1421 if (per_cpu(xen_vcpu
, cpu
) == NULL
)
1424 xen_setup_timer(cpu
);
1426 rc
= xen_smp_intr_init(cpu
);
1428 WARN(1, "xen_smp_intr_init() for CPU %d failed: %d\n",
1433 rc
= xen_smp_intr_init_pv(cpu
);
1435 WARN(1, "xen_smp_intr_init_pv() for CPU %d failed: %d\n",
1443 static int xen_cpu_dead_pv(unsigned int cpu
)
1445 xen_smp_intr_free(cpu
);
1446 xen_smp_intr_free_pv(cpu
);
1448 xen_teardown_timer(cpu
);
1453 static uint32_t __init
xen_platform_pv(void)
1455 if (xen_pv_domain())
1456 return xen_cpuid_base();
1461 const __initconst
struct hypervisor_x86 x86_hyper_xen_pv
= {
1463 .detect
= xen_platform_pv
,
1464 .type
= X86_HYPER_XEN_PV
,
1465 .runtime
.pin_vcpu
= xen_pin_vcpu
,