arch/x86/xen/enlighten_hvm.c

   1 // SPDX-License-Identifier: GPL-2.0
   2
   3 #include <linux/acpi.h>
   4 #include <linux/cpu.h>
   5 #include <linux/kexec.h>
   6 #include <linux/memblock.h>
   7
   8 #include <xen/features.h>
   9 #include <xen/events.h>
  10 #include <xen/interface/memory.h>
  11
  12 #include <asm/cpu.h>
  13 #include <asm/smp.h>
  14 #include <asm/io_apic.h>
  15 #include <asm/reboot.h>
  16 #include <asm/setup.h>
  17 #include <asm/idtentry.h>
  18 #include <asm/hypervisor.h>
  19 #include <asm/e820/api.h>
  20 #include <asm/early_ioremap.h>
  21
  22 #include <asm/xen/cpuid.h>
  23 #include <asm/xen/hypervisor.h>
  24 #include <asm/xen/page.h>
  25
  26 #include "xen-ops.h"
  27 #include "mmu.h"
  28 #include "smp.h"
  29
  30 static unsigned long shared_info_pfn;
  31
  32 void xen_hvm_init_shared_info(void)
  33 {
  34         struct xen_add_to_physmap xatp;
  35
  36         xatp.domid = DOMID_SELF;
  37         xatp.idx = 0;
  38         xatp.space = XENMAPSPACE_shared_info;
  39         xatp.gpfn = shared_info_pfn;
  40         if (HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp))
  41                 BUG();
  42 }
  43
  44 static void __init reserve_shared_info(void)
  45 {
  46         u64 pa;
  47
  48         /*
  49          * Search for a free page starting at 4kB physical address.
  50          * Low memory is preferred to avoid an EPT large page split up
  51          * by the mapping.
  52          * Starting below X86_RESERVE_LOW (usually 64kB) is fine as
  53          * the BIOS used for HVM guests is well behaved and won't
  54          * clobber memory other than the first 4kB.
  55          */
  56         for (pa = PAGE_SIZE;
  57              !e820__mapped_all(pa, pa + PAGE_SIZE, E820_TYPE_RAM) ||
  58              memblock_is_reserved(pa);
  59              pa += PAGE_SIZE)
  60                 ;
  61
  62         shared_info_pfn = PHYS_PFN(pa);
  63
  64         memblock_reserve(pa, PAGE_SIZE);
  65         HYPERVISOR_shared_info = early_memremap(pa, PAGE_SIZE);
  66 }
  67
  68 static void __init xen_hvm_init_mem_mapping(void)
  69 {
  70         early_memunmap(HYPERVISOR_shared_info, PAGE_SIZE);
  71         HYPERVISOR_shared_info = __va(PFN_PHYS(shared_info_pfn));
  72
  73         /*
  74          * The virtual address of the shared_info page has changed, so
  75          * the vcpu_info pointer for VCPU 0 is now stale.
  76          *
  77          * The prepare_boot_cpu callback will re-initialize it via
  78          * xen_vcpu_setup, but we can't rely on that to be called for
  79          * old Xen versions (xen_have_vector_callback == 0).
  80          *
  81          * It is, in any case, bad to have a stale vcpu_info pointer
  82          * so reset it now.
  83          */
  84         xen_vcpu_info_reset(0);
  85 }
  86
  87 static void __init init_hvm_pv_info(void)
  88 {
  89         int major, minor;
  90         uint32_t eax, ebx, ecx, edx, base;
  91
  92         base = xen_cpuid_base();
  93         eax = cpuid_eax(base + 1);
  94
  95         major = eax >> 16;
  96         minor = eax & 0xffff;
  97         printk(KERN_INFO "Xen version %d.%d.\n", major, minor);
  98
  99         xen_domain_type = XEN_HVM_DOMAIN;
 100
 101         /* PVH set up hypercall page in xen_prepare_pvh(). */
 102         if (xen_pvh_domain())
 103                 pv_info.name = "Xen PVH";
 104         else {
 105                 u64 pfn;
 106                 uint32_t msr;
 107
 108                 pv_info.name = "Xen HVM";
 109                 msr = cpuid_ebx(base + 2);
 110                 pfn = __pa(hypercall_page);
 111                 wrmsr_safe(msr, (u32)pfn, (u32)(pfn >> 32));
 112         }
 113
 114         xen_setup_features();
 115
 116         cpuid(base + 4, &eax, &ebx, &ecx, &edx);
 117         if (eax & XEN_HVM_CPUID_VCPU_ID_PRESENT)
 118                 this_cpu_write(xen_vcpu_id, ebx);
 119         else
 120                 this_cpu_write(xen_vcpu_id, smp_processor_id());
 121 }
 122
 123 DEFINE_IDTENTRY_SYSVEC(sysvec_xen_hvm_callback)
 124 {
 125         struct pt_regs *old_regs = set_irq_regs(regs);
 126
 127         inc_irq_stat(irq_hv_callback_count);
 128
 129         xen_hvm_evtchn_do_upcall();
 130
 131         set_irq_regs(old_regs);
 132 }
 133
 134 #ifdef CONFIG_KEXEC_CORE
 135 static void xen_hvm_shutdown(void)
 136 {
 137         native_machine_shutdown();
 138         if (kexec_in_progress)
 139                 xen_reboot(SHUTDOWN_soft_reset);
 140 }
 141
 142 static void xen_hvm_crash_shutdown(struct pt_regs *regs)
 143 {
 144         native_machine_crash_shutdown(regs);
 145         xen_reboot(SHUTDOWN_soft_reset);
 146 }
 147 #endif
 148
 149 static int xen_cpu_up_prepare_hvm(unsigned int cpu)
 150 {
 151         int rc = 0;
 152
 153         /*
 154          * This can happen if CPU was offlined earlier and
 155          * offlining timed out in common_cpu_die().
 156          */
 157         if (cpu_report_state(cpu) == CPU_DEAD_FROZEN) {
 158                 xen_smp_intr_free(cpu);
 159                 xen_uninit_lock_cpu(cpu);
 160         }
 161
 162         if (cpu_acpi_id(cpu) != U32_MAX)
 163                 per_cpu(xen_vcpu_id, cpu) = cpu_acpi_id(cpu);
 164         else
 165                 per_cpu(xen_vcpu_id, cpu) = cpu;
 166         xen_vcpu_setup(cpu);
 167         if (!xen_have_vector_callback)
 168                 return 0;
 169
 170         if (xen_feature(XENFEAT_hvm_safe_pvclock))
 171                 xen_setup_timer(cpu);
 172
 173         rc = xen_smp_intr_init(cpu);
 174         if (rc) {
 175                 WARN(1, "xen_smp_intr_init() for CPU %d failed: %d\n",
 176                      cpu, rc);
 177         }
 178         return rc;
 179 }
 180
 181 static int xen_cpu_dead_hvm(unsigned int cpu)
 182 {
 183         xen_smp_intr_free(cpu);
 184
 185         if (xen_have_vector_callback && xen_feature(XENFEAT_hvm_safe_pvclock))
 186                 xen_teardown_timer(cpu);
 187
 188        return 0;
 189 }
 190
 191 static bool no_vector_callback __initdata;
 192
 193 static void __init xen_hvm_guest_init(void)
 194 {
 195         if (xen_pv_domain())
 196                 return;
 197
 198         init_hvm_pv_info();
 199
 200         reserve_shared_info();
 201         xen_hvm_init_shared_info();
 202
 203         /*
 204          * xen_vcpu is a pointer to the vcpu_info struct in the shared_info
 205          * page, we use it in the event channel upcall and in some pvclock
 206          * related functions.
 207          */
 208         xen_vcpu_info_reset(0);
 209
 210         xen_panic_handler_init();
 211
 212         if (!no_vector_callback && xen_feature(XENFEAT_hvm_callback_vector))
 213                 xen_have_vector_callback = 1;
 214
 215         xen_hvm_smp_init();
 216         WARN_ON(xen_cpuhp_setup(xen_cpu_up_prepare_hvm, xen_cpu_dead_hvm));
 217         xen_unplug_emulated_devices();
 218         x86_init.irqs.intr_init = xen_init_IRQ;
 219         xen_hvm_init_time_ops();
 220         xen_hvm_init_mmu_ops();
 221
 222 #ifdef CONFIG_KEXEC_CORE
 223         machine_ops.shutdown = xen_hvm_shutdown;
 224         machine_ops.crash_shutdown = xen_hvm_crash_shutdown;
 225 #endif
 226 }
 227
 228 static __init int xen_parse_nopv(char *arg)
 229 {
 230         pr_notice("\"xen_nopv\" is deprecated, please use \"nopv\" instead\n");
 231
 232         if (xen_cpuid_base())
 233                 nopv = true;
 234         return 0;
 235 }
 236 early_param("xen_nopv", xen_parse_nopv);
 237
 238 static __init int xen_parse_no_vector_callback(char *arg)
 239 {
 240         no_vector_callback = true;
 241         return 0;
 242 }
 243 early_param("xen_no_vector_callback", xen_parse_no_vector_callback);
 244
 245 bool __init xen_hvm_need_lapic(void)
 246 {
 247         if (xen_pv_domain())
 248                 return false;
 249         if (!xen_hvm_domain())
 250                 return false;
 251         if (xen_feature(XENFEAT_hvm_pirqs) && xen_have_vector_callback)
 252                 return false;
 253         return true;
 254 }
 255
 256 static __init void xen_hvm_guest_late_init(void)
 257 {
 258 #ifdef CONFIG_XEN_PVH
 259         /* Test for PVH domain (PVH boot path taken overrides ACPI flags). */
 260         if (!xen_pvh &&
 261             (x86_platform.legacy.rtc || !x86_platform.legacy.no_vga))
 262                 return;
 263
 264         /* PVH detected. */
 265         xen_pvh = true;
 266
 267         if (nopv)
 268                 panic("\"nopv\" and \"xen_nopv\" parameters are unsupported in PVH guest.");
 269
 270         /* Make sure we don't fall back to (default) ACPI_IRQ_MODEL_PIC. */
 271         if (!nr_ioapics && acpi_irq_model == ACPI_IRQ_MODEL_PIC)
 272                 acpi_irq_model = ACPI_IRQ_MODEL_PLATFORM;
 273
 274         machine_ops.emergency_restart = xen_emergency_restart;
 275         pv_info.name = "Xen PVH";
 276 #endif
 277 }
 278
 279 static uint32_t __init xen_platform_hvm(void)
 280 {
 281         uint32_t xen_domain = xen_cpuid_base();
 282         struct x86_hyper_init *h = &x86_hyper_xen_hvm.init;
 283
 284         if (xen_pv_domain())
 285                 return 0;
 286
 287         if (xen_pvh_domain() && nopv) {
 288                 /* Guest booting via the Xen-PVH boot entry goes here */
 289                 pr_info("\"nopv\" parameter is ignored in PVH guest\n");
 290                 nopv = false;
 291         } else if (nopv && xen_domain) {
 292                 /*
 293                  * Guest booting via normal boot entry (like via grub2) goes
 294                  * here.
 295                  *
 296                  * Use interface functions for bare hardware if nopv,
 297                  * xen_hvm_guest_late_init is an exception as we need to
 298                  * detect PVH and panic there.
 299                  */
 300                 h->init_platform = x86_init_noop;
 301                 h->x2apic_available = bool_x86_init_noop;
 302                 h->init_mem_mapping = x86_init_noop;
 303                 h->init_after_bootmem = x86_init_noop;
 304                 h->guest_late_init = xen_hvm_guest_late_init;
 305                 x86_hyper_xen_hvm.runtime.pin_vcpu = x86_op_int_noop;
 306         }
 307         return xen_domain;
 308 }
 309
 310 struct hypervisor_x86 x86_hyper_xen_hvm __initdata = {
 311         .name                   = "Xen HVM",
 312         .detect                 = xen_platform_hvm,
 313         .type                   = X86_HYPER_XEN_HVM,
 314         .init.init_platform     = xen_hvm_guest_init,
 315         .init.x2apic_available  = xen_x2apic_para_available,
 316         .init.init_mem_mapping  = xen_hvm_init_mem_mapping,
 317         .init.guest_late_init   = xen_hvm_guest_late_init,
 318         .runtime.pin_vcpu       = xen_pin_vcpu,
 319         .ignore_nopv            = true,
 320 };