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 #include <linux/virtio_anchor.h>
   8
   9 #include <xen/features.h>
  10 #include <xen/events.h>
  11 #include <xen/hvm.h>
  12 #include <xen/interface/hvm/hvm_op.h>
  13 #include <xen/interface/memory.h>
  14
  15 #include <asm/apic.h>
  16 #include <asm/cpu.h>
  17 #include <asm/smp.h>
  18 #include <asm/io_apic.h>
  19 #include <asm/reboot.h>
  20 #include <asm/setup.h>
  21 #include <asm/idtentry.h>
  22 #include <asm/hypervisor.h>
  23 #include <asm/e820/api.h>
  24 #include <asm/early_ioremap.h>
  25
  26 #include <asm/xen/cpuid.h>
  27 #include <asm/xen/hypervisor.h>
  28 #include <asm/xen/page.h>
  29
  30 #include "xen-ops.h"
  31
  32 static unsigned long shared_info_pfn;
  33
  34 __ro_after_init bool xen_percpu_upcall;
  35 EXPORT_SYMBOL_GPL(xen_percpu_upcall);
  36
  37 void xen_hvm_init_shared_info(void)
  38 {
  39         struct xen_add_to_physmap xatp;
  40
  41         xatp.domid = DOMID_SELF;
  42         xatp.idx = 0;
  43         xatp.space = XENMAPSPACE_shared_info;
  44         xatp.gpfn = shared_info_pfn;
  45         if (HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp))
  46                 BUG();
  47 }
  48
  49 static void __init reserve_shared_info(void)
  50 {
  51         u64 pa;
  52
  53         /*
  54          * Search for a free page starting at 4kB physical address.
  55          * Low memory is preferred to avoid an EPT large page split up
  56          * by the mapping.
  57          * Starting below X86_RESERVE_LOW (usually 64kB) is fine as
  58          * the BIOS used for HVM guests is well behaved and won't
  59          * clobber memory other than the first 4kB.
  60          */
  61         for (pa = PAGE_SIZE;
  62              !e820__mapped_all(pa, pa + PAGE_SIZE, E820_TYPE_RAM) ||
  63              memblock_is_reserved(pa);
  64              pa += PAGE_SIZE)
  65                 ;
  66
  67         shared_info_pfn = PHYS_PFN(pa);
  68
  69         memblock_reserve(pa, PAGE_SIZE);
  70         HYPERVISOR_shared_info = early_memremap(pa, PAGE_SIZE);
  71 }
  72
  73 static void __init xen_hvm_init_mem_mapping(void)
  74 {
  75         early_memunmap(HYPERVISOR_shared_info, PAGE_SIZE);
  76         HYPERVISOR_shared_info = __va(PFN_PHYS(shared_info_pfn));
  77
  78         /*
  79          * The virtual address of the shared_info page has changed, so
  80          * the vcpu_info pointer for VCPU 0 is now stale.
  81          *
  82          * The prepare_boot_cpu callback will re-initialize it via
  83          * xen_vcpu_setup, but we can't rely on that to be called for
  84          * old Xen versions (xen_have_vector_callback == 0).
  85          *
  86          * It is, in any case, bad to have a stale vcpu_info pointer
  87          * so reset it now.
  88          */
  89         xen_vcpu_info_reset(0);
  90 }
  91
  92 static void __init init_hvm_pv_info(void)
  93 {
  94         int major, minor;
  95         uint32_t eax, ebx, ecx, edx, base;
  96
  97         base = xen_cpuid_base();
  98         eax = cpuid_eax(base + 1);
  99
 100         major = eax >> 16;
 101         minor = eax & 0xffff;
 102         printk(KERN_INFO "Xen version %d.%d.\n", major, minor);
 103
 104         xen_domain_type = XEN_HVM_DOMAIN;
 105
 106         /* PVH set up hypercall page in xen_prepare_pvh(). */
 107         if (xen_pvh_domain())
 108                 pv_info.name = "Xen PVH";
 109         else {
 110                 u64 pfn;
 111                 uint32_t msr;
 112
 113                 pv_info.name = "Xen HVM";
 114                 msr = cpuid_ebx(base + 2);
 115                 pfn = __pa(hypercall_page);
 116                 wrmsr_safe(msr, (u32)pfn, (u32)(pfn >> 32));
 117         }
 118
 119         xen_setup_features();
 120
 121         cpuid(base + 4, &eax, &ebx, &ecx, &edx);
 122         if (eax & XEN_HVM_CPUID_VCPU_ID_PRESENT)
 123                 this_cpu_write(xen_vcpu_id, ebx);
 124         else
 125                 this_cpu_write(xen_vcpu_id, smp_processor_id());
 126 }
 127
 128 DEFINE_IDTENTRY_SYSVEC(sysvec_xen_hvm_callback)
 129 {
 130         struct pt_regs *old_regs = set_irq_regs(regs);
 131
 132         if (xen_percpu_upcall)
 133                 apic_eoi();
 134
 135         inc_irq_stat(irq_hv_callback_count);
 136
 137         xen_evtchn_do_upcall();
 138
 139         set_irq_regs(old_regs);
 140 }
 141
 142 #ifdef CONFIG_KEXEC_CORE
 143 static void xen_hvm_shutdown(void)
 144 {
 145         native_machine_shutdown();
 146         if (kexec_in_progress)
 147                 xen_reboot(SHUTDOWN_soft_reset);
 148 }
 149 #endif
 150
 151 #ifdef CONFIG_CRASH_DUMP
 152 static void xen_hvm_crash_shutdown(struct pt_regs *regs)
 153 {
 154         native_machine_crash_shutdown(regs);
 155         xen_reboot(SHUTDOWN_soft_reset);
 156 }
 157 #endif
 158
 159 static int xen_cpu_up_prepare_hvm(unsigned int cpu)
 160 {
 161         int rc = 0;
 162
 163         /*
 164          * If a CPU was offlined earlier and offlining timed out then the
 165          * lock mechanism is still initialized. Uninit it unconditionally
 166          * as it's safe to call even if already uninited. Interrupts and
 167          * timer have already been handled in xen_cpu_dead_hvm().
 168          */
 169         xen_uninit_lock_cpu(cpu);
 170
 171         if (cpu_acpi_id(cpu) != CPU_ACPIID_INVALID)
 172                 per_cpu(xen_vcpu_id, cpu) = cpu_acpi_id(cpu);
 173         else
 174                 per_cpu(xen_vcpu_id, cpu) = cpu;
 175         xen_vcpu_setup(cpu);
 176         if (!xen_have_vector_callback)
 177                 return 0;
 178
 179         if (xen_percpu_upcall) {
 180                 rc = xen_set_upcall_vector(cpu);
 181                 if (rc) {
 182                         WARN(1, "HVMOP_set_evtchn_upcall_vector"
 183                              " for CPU %d failed: %d\n", cpu, rc);
 184                         return rc;
 185                 }
 186         }
 187
 188         if (xen_feature(XENFEAT_hvm_safe_pvclock))
 189                 xen_setup_timer(cpu);
 190
 191         rc = xen_smp_intr_init(cpu);
 192         if (rc) {
 193                 WARN(1, "xen_smp_intr_init() for CPU %d failed: %d\n",
 194                      cpu, rc);
 195         }
 196         return rc;
 197 }
 198
 199 static int xen_cpu_dead_hvm(unsigned int cpu)
 200 {
 201         xen_smp_intr_free(cpu);
 202
 203         if (xen_have_vector_callback && xen_feature(XENFEAT_hvm_safe_pvclock))
 204                 xen_teardown_timer(cpu);
 205         return 0;
 206 }
 207
 208 static void __init xen_hvm_guest_init(void)
 209 {
 210         if (xen_pv_domain())
 211                 return;
 212
 213         if (IS_ENABLED(CONFIG_XEN_VIRTIO_FORCE_GRANT))
 214                 virtio_set_mem_acc_cb(xen_virtio_restricted_mem_acc);
 215
 216         init_hvm_pv_info();
 217
 218         reserve_shared_info();
 219         xen_hvm_init_shared_info();
 220
 221         /*
 222          * xen_vcpu is a pointer to the vcpu_info struct in the shared_info
 223          * page, we use it in the event channel upcall and in some pvclock
 224          * related functions.
 225          */
 226         xen_vcpu_info_reset(0);
 227
 228         xen_panic_handler_init();
 229
 230         xen_hvm_smp_init();
 231         WARN_ON(xen_cpuhp_setup(xen_cpu_up_prepare_hvm, xen_cpu_dead_hvm));
 232         xen_unplug_emulated_devices();
 233         x86_init.irqs.intr_init = xen_init_IRQ;
 234         xen_hvm_init_time_ops();
 235         xen_hvm_init_mmu_ops();
 236
 237 #ifdef CONFIG_KEXEC_CORE
 238         machine_ops.shutdown = xen_hvm_shutdown;
 239 #endif
 240 #ifdef CONFIG_CRASH_DUMP
 241         machine_ops.crash_shutdown = xen_hvm_crash_shutdown;
 242 #endif
 243 }
 244
 245 static __init int xen_parse_nopv(char *arg)
 246 {
 247         pr_notice("\"xen_nopv\" is deprecated, please use \"nopv\" instead\n");
 248
 249         if (xen_cpuid_base())
 250                 nopv = true;
 251         return 0;
 252 }
 253 early_param("xen_nopv", xen_parse_nopv);
 254
 255 static __init int xen_parse_no_vector_callback(char *arg)
 256 {
 257         xen_have_vector_callback = false;
 258         return 0;
 259 }
 260 early_param("xen_no_vector_callback", xen_parse_no_vector_callback);
 261
 262 static __init bool xen_x2apic_available(void)
 263 {
 264         return x2apic_supported();
 265 }
 266
 267 static bool __init msi_ext_dest_id(void)
 268 {
 269        return cpuid_eax(xen_cpuid_base() + 4) & XEN_HVM_CPUID_EXT_DEST_ID;
 270 }
 271
 272 static __init void xen_hvm_guest_late_init(void)
 273 {
 274 #ifdef CONFIG_XEN_PVH
 275         /* Test for PVH domain (PVH boot path taken overrides ACPI flags). */
 276         if (!xen_pvh &&
 277             (x86_platform.legacy.rtc || !x86_platform.legacy.no_vga))
 278                 return;
 279
 280         /* PVH detected. */
 281         xen_pvh = true;
 282
 283         if (nopv)
 284                 panic("\"nopv\" and \"xen_nopv\" parameters are unsupported in PVH guest.");
 285
 286         /* Make sure we don't fall back to (default) ACPI_IRQ_MODEL_PIC. */
 287         if (!nr_ioapics && acpi_irq_model == ACPI_IRQ_MODEL_PIC)
 288                 acpi_irq_model = ACPI_IRQ_MODEL_PLATFORM;
 289
 290         machine_ops.emergency_restart = xen_emergency_restart;
 291         pv_info.name = "Xen PVH";
 292 #endif
 293 }
 294
 295 static uint32_t __init xen_platform_hvm(void)
 296 {
 297         uint32_t xen_domain = xen_cpuid_base();
 298         struct x86_hyper_init *h = &x86_hyper_xen_hvm.init;
 299
 300         if (xen_pv_domain())
 301                 return 0;
 302
 303         if (xen_pvh_domain() && nopv) {
 304                 /* Guest booting via the Xen-PVH boot entry goes here */
 305                 pr_info("\"nopv\" parameter is ignored in PVH guest\n");
 306                 nopv = false;
 307         } else if (nopv && xen_domain) {
 308                 /*
 309                  * Guest booting via normal boot entry (like via grub2) goes
 310                  * here.
 311                  *
 312                  * Use interface functions for bare hardware if nopv,
 313                  * xen_hvm_guest_late_init is an exception as we need to
 314                  * detect PVH and panic there.
 315                  */
 316                 h->init_platform = x86_init_noop;
 317                 h->x2apic_available = bool_x86_init_noop;
 318                 h->init_mem_mapping = x86_init_noop;
 319                 h->init_after_bootmem = x86_init_noop;
 320                 h->guest_late_init = xen_hvm_guest_late_init;
 321                 x86_hyper_xen_hvm.runtime.pin_vcpu = x86_op_int_noop;
 322         }
 323         return xen_domain;
 324 }
 325
 326 struct hypervisor_x86 x86_hyper_xen_hvm __initdata = {
 327         .name                   = "Xen HVM",
 328         .detect                 = xen_platform_hvm,
 329         .type                   = X86_HYPER_XEN_HVM,
 330         .init.init_platform     = xen_hvm_guest_init,
 331         .init.x2apic_available  = xen_x2apic_available,
 332         .init.init_mem_mapping  = xen_hvm_init_mem_mapping,
 333         .init.guest_late_init   = xen_hvm_guest_late_init,
 334         .init.msi_ext_dest_id   = msi_ext_dest_id,
 335         .runtime.pin_vcpu       = xen_pin_vcpu,
 336         .ignore_nopv            = true,
 337 };