arch/x86/xen/enlighten_hvm.c

   1 #include <linux/cpu.h>
   2 #include <linux/kexec.h>
   3 #include <linux/memblock.h>
   4
   5 #include <xen/features.h>
   6 #include <xen/events.h>
   7 #include <xen/interface/memory.h>
   8
   9 #include <asm/cpu.h>
  10 #include <asm/smp.h>
  11 #include <asm/reboot.h>
  12 #include <asm/setup.h>
  13 #include <asm/hypervisor.h>
  14 #include <asm/e820/api.h>
  15 #include <asm/early_ioremap.h>
  16
  17 #include <asm/xen/cpuid.h>
  18 #include <asm/xen/hypervisor.h>
  19 #include <asm/xen/page.h>
  20
  21 #include "xen-ops.h"
  22 #include "mmu.h"
  23 #include "smp.h"
  24
  25 static unsigned long shared_info_pfn;
  26
  27 void xen_hvm_init_shared_info(void)
  28 {
  29         struct xen_add_to_physmap xatp;
  30
  31         xatp.domid = DOMID_SELF;
  32         xatp.idx = 0;
  33         xatp.space = XENMAPSPACE_shared_info;
  34         xatp.gpfn = shared_info_pfn;
  35         if (HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp))
  36                 BUG();
  37 }
  38
  39 static void __init reserve_shared_info(void)
  40 {
  41         u64 pa;
  42
  43         /*
  44          * Search for a free page starting at 4kB physical address.
  45          * Low memory is preferred to avoid an EPT large page split up
  46          * by the mapping.
  47          * Starting below X86_RESERVE_LOW (usually 64kB) is fine as
  48          * the BIOS used for HVM guests is well behaved and won't
  49          * clobber memory other than the first 4kB.
  50          */
  51         for (pa = PAGE_SIZE;
  52              !e820__mapped_all(pa, pa + PAGE_SIZE, E820_TYPE_RAM) ||
  53              memblock_is_reserved(pa);
  54              pa += PAGE_SIZE)
  55                 ;
  56
  57         shared_info_pfn = PHYS_PFN(pa);
  58
  59         memblock_reserve(pa, PAGE_SIZE);
  60         HYPERVISOR_shared_info = early_memremap(pa, PAGE_SIZE);
  61 }
  62
  63 static void __init xen_hvm_init_mem_mapping(void)
  64 {
  65         early_memunmap(HYPERVISOR_shared_info, PAGE_SIZE);
  66         HYPERVISOR_shared_info = __va(PFN_PHYS(shared_info_pfn));
  67
  68         /*
  69          * The virtual address of the shared_info page has changed, so
  70          * the vcpu_info pointer for VCPU 0 is now stale.
  71          *
  72          * The prepare_boot_cpu callback will re-initialize it via
  73          * xen_vcpu_setup, but we can't rely on that to be called for
  74          * old Xen versions (xen_have_vector_callback == 0).
  75          *
  76          * It is, in any case, bad to have a stale vcpu_info pointer
  77          * so reset it now.
  78          */
  79         xen_vcpu_info_reset(0);
  80 }
  81
  82 static void __init init_hvm_pv_info(void)
  83 {
  84         int major, minor;
  85         uint32_t eax, ebx, ecx, edx, base;
  86
  87         base = xen_cpuid_base();
  88         eax = cpuid_eax(base + 1);
  89
  90         major = eax >> 16;
  91         minor = eax & 0xffff;
  92         printk(KERN_INFO "Xen version %d.%d.\n", major, minor);
  93
  94         xen_domain_type = XEN_HVM_DOMAIN;
  95
  96         /* PVH set up hypercall page in xen_prepare_pvh(). */
  97         if (xen_pvh_domain())
  98                 pv_info.name = "Xen PVH";
  99         else {
 100                 u64 pfn;
 101                 uint32_t msr;
 102
 103                 pv_info.name = "Xen HVM";
 104                 msr = cpuid_ebx(base + 2);
 105                 pfn = __pa(hypercall_page);
 106                 wrmsr_safe(msr, (u32)pfn, (u32)(pfn >> 32));
 107         }
 108
 109         xen_setup_features();
 110
 111         cpuid(base + 4, &eax, &ebx, &ecx, &edx);
 112         if (eax & XEN_HVM_CPUID_VCPU_ID_PRESENT)
 113                 this_cpu_write(xen_vcpu_id, ebx);
 114         else
 115                 this_cpu_write(xen_vcpu_id, smp_processor_id());
 116 }
 117
 118 #ifdef CONFIG_KEXEC_CORE
 119 static void xen_hvm_shutdown(void)
 120 {
 121         native_machine_shutdown();
 122         if (kexec_in_progress)
 123                 xen_reboot(SHUTDOWN_soft_reset);
 124 }
 125
 126 static void xen_hvm_crash_shutdown(struct pt_regs *regs)
 127 {
 128         native_machine_crash_shutdown(regs);
 129         xen_reboot(SHUTDOWN_soft_reset);
 130 }
 131 #endif
 132
 133 static int xen_cpu_up_prepare_hvm(unsigned int cpu)
 134 {
 135         int rc = 0;
 136
 137         /*
 138          * This can happen if CPU was offlined earlier and
 139          * offlining timed out in common_cpu_die().
 140          */
 141         if (cpu_report_state(cpu) == CPU_DEAD_FROZEN) {
 142                 xen_smp_intr_free(cpu);
 143                 xen_uninit_lock_cpu(cpu);
 144         }
 145
 146         if (cpu_acpi_id(cpu) != U32_MAX)
 147                 per_cpu(xen_vcpu_id, cpu) = cpu_acpi_id(cpu);
 148         else
 149                 per_cpu(xen_vcpu_id, cpu) = cpu;
 150         rc = xen_vcpu_setup(cpu);
 151         if (rc)
 152                 return rc;
 153
 154         if (xen_have_vector_callback && xen_feature(XENFEAT_hvm_safe_pvclock))
 155                 xen_setup_timer(cpu);
 156
 157         rc = xen_smp_intr_init(cpu);
 158         if (rc) {
 159                 WARN(1, "xen_smp_intr_init() for CPU %d failed: %d\n",
 160                      cpu, rc);
 161         }
 162         return rc;
 163 }
 164
 165 static int xen_cpu_dead_hvm(unsigned int cpu)
 166 {
 167         xen_smp_intr_free(cpu);
 168
 169         if (xen_have_vector_callback && xen_feature(XENFEAT_hvm_safe_pvclock))
 170                 xen_teardown_timer(cpu);
 171
 172        return 0;
 173 }
 174
 175 static void __init xen_hvm_guest_init(void)
 176 {
 177         if (xen_pv_domain())
 178                 return;
 179
 180         init_hvm_pv_info();
 181
 182         reserve_shared_info();
 183         xen_hvm_init_shared_info();
 184
 185         /*
 186          * xen_vcpu is a pointer to the vcpu_info struct in the shared_info
 187          * page, we use it in the event channel upcall and in some pvclock
 188          * related functions.
 189          */
 190         xen_vcpu_info_reset(0);
 191
 192         xen_panic_handler_init();
 193
 194         if (xen_feature(XENFEAT_hvm_callback_vector))
 195                 xen_have_vector_callback = 1;
 196
 197         xen_hvm_smp_init();
 198         WARN_ON(xen_cpuhp_setup(xen_cpu_up_prepare_hvm, xen_cpu_dead_hvm));
 199         xen_unplug_emulated_devices();
 200         x86_init.irqs.intr_init = xen_init_IRQ;
 201         xen_hvm_init_time_ops();
 202         xen_hvm_init_mmu_ops();
 203
 204         if (xen_pvh_domain())
 205                 machine_ops.emergency_restart = xen_emergency_restart;
 206 #ifdef CONFIG_KEXEC_CORE
 207         machine_ops.shutdown = xen_hvm_shutdown;
 208         machine_ops.crash_shutdown = xen_hvm_crash_shutdown;
 209 #endif
 210 }
 211
 212 static bool xen_nopv;
 213 static __init int xen_parse_nopv(char *arg)
 214 {
 215        xen_nopv = true;
 216        return 0;
 217 }
 218 early_param("xen_nopv", xen_parse_nopv);
 219
 220 bool xen_hvm_need_lapic(void)
 221 {
 222         if (xen_nopv)
 223                 return false;
 224         if (xen_pv_domain())
 225                 return false;
 226         if (!xen_hvm_domain())
 227                 return false;
 228         if (xen_feature(XENFEAT_hvm_pirqs) && xen_have_vector_callback)
 229                 return false;
 230         return true;
 231 }
 232 EXPORT_SYMBOL_GPL(xen_hvm_need_lapic);
 233
 234 static uint32_t __init xen_platform_hvm(void)
 235 {
 236         if (xen_pv_domain() || xen_nopv)
 237                 return 0;
 238
 239         return xen_cpuid_base();
 240 }
 241
 242 const __initconst struct hypervisor_x86 x86_hyper_xen_hvm = {
 243         .name                   = "Xen HVM",
 244         .detect                 = xen_platform_hvm,
 245         .type                   = X86_HYPER_XEN_HVM,
 246         .init.init_platform     = xen_hvm_guest_init,
 247         .init.x2apic_available  = xen_x2apic_para_available,
 248         .init.init_mem_mapping  = xen_hvm_init_mem_mapping,
 249         .runtime.pin_vcpu       = xen_pin_vcpu,
 250 };