x86/xen/enlighten_hvm.c

0001 // SPDX-License-Identifier: GPL-2.0
0002
0003 #include <linux/acpi.h>
0004 #include <linux/cpu.h>
0005 #include <linux/kexec.h>
0006 #include <linux/memblock.h>
0007 #include <linux/virtio_anchor.h>
0008
0009 #include <xen/features.h>
0010 #include <xen/events.h>
0011 #include <xen/hvm.h>
0012 #include <xen/interface/hvm/hvm_op.h>
0013 #include <xen/interface/memory.h>
0014
0015 #include <asm/apic.h>
0016 #include <asm/cpu.h>
0017 #include <asm/smp.h>
0018 #include <asm/io_apic.h>
0019 #include <asm/reboot.h>
0020 #include <asm/setup.h>
0021 #include <asm/idtentry.h>
0022 #include <asm/hypervisor.h>
0023 #include <asm/e820/api.h>
0024 #include <asm/early_ioremap.h>
0025
0026 #include <asm/xen/cpuid.h>
0027 #include <asm/xen/hypervisor.h>
0028 #include <asm/xen/page.h>
0029
0030 #include "xen-ops.h"
0031 #include "mmu.h"
0032 #include "smp.h"
0033
0034 static unsigned long shared_info_pfn;
0035
0036 __ro_after_init bool xen_percpu_upcall;
0037 EXPORT_SYMBOL_GPL(xen_percpu_upcall);
0038
0039 void xen_hvm_init_shared_info(void)
0040 {
0041     struct xen_add_to_physmap xatp;
0042
0043     xatp.domid = DOMID_SELF;
0044     xatp.idx = 0;
0045     xatp.space = XENMAPSPACE_shared_info;
0046     xatp.gpfn = shared_info_pfn;
0047     if (HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp))
0048         BUG();
0049 }
0050
0051 static void __init reserve_shared_info(void)
0052 {
0053     u64 pa;
0054
0055     /*
0056      * Search for a free page starting at 4kB physical address.
0057      * Low memory is preferred to avoid an EPT large page split up
0058      * by the mapping.
0059      * Starting below X86_RESERVE_LOW (usually 64kB) is fine as
0060      * the BIOS used for HVM guests is well behaved and won't
0061      * clobber memory other than the first 4kB.
0062      */
0063     for (pa = PAGE_SIZE;
0064          !e820__mapped_all(pa, pa + PAGE_SIZE, E820_TYPE_RAM) ||
0065          memblock_is_reserved(pa);
0066          pa += PAGE_SIZE)
0067         ;
0068
0069     shared_info_pfn = PHYS_PFN(pa);
0070
0071     memblock_reserve(pa, PAGE_SIZE);
0072     HYPERVISOR_shared_info = early_memremap(pa, PAGE_SIZE);
0073 }
0074
0075 static void __init xen_hvm_init_mem_mapping(void)
0076 {
0077     early_memunmap(HYPERVISOR_shared_info, PAGE_SIZE);
0078     HYPERVISOR_shared_info = __va(PFN_PHYS(shared_info_pfn));
0079
0080     /*
0081      * The virtual address of the shared_info page has changed, so
0082      * the vcpu_info pointer for VCPU 0 is now stale.
0083      *
0084      * The prepare_boot_cpu callback will re-initialize it via
0085      * xen_vcpu_setup, but we can't rely on that to be called for
0086      * old Xen versions (xen_have_vector_callback == 0).
0087      *
0088      * It is, in any case, bad to have a stale vcpu_info pointer
0089      * so reset it now.
0090      */
0091     xen_vcpu_info_reset(0);
0092 }
0093
0094 static void __init init_hvm_pv_info(void)
0095 {
0096     int major, minor;
0097     uint32_t eax, ebx, ecx, edx, base;
0098
0099     base = xen_cpuid_base();
0100     eax = cpuid_eax(base + 1);
0101
0102     major = eax >> 16;
0103     minor = eax & 0xffff;
0104     printk(KERN_INFO "Xen version %d.%d.\n", major, minor);
0105
0106     xen_domain_type = XEN_HVM_DOMAIN;
0107
0108     /* PVH set up hypercall page in xen_prepare_pvh(). */
0109     if (xen_pvh_domain())
0110         pv_info.name = "Xen PVH";
0111     else {
0112         u64 pfn;
0113         uint32_t msr;
0114
0115         pv_info.name = "Xen HVM";
0116         msr = cpuid_ebx(base + 2);
0117         pfn = __pa(hypercall_page);
0118         wrmsr_safe(msr, (u32)pfn, (u32)(pfn >> 32));
0119     }
0120
0121     xen_setup_features();
0122
0123     cpuid(base + 4, &eax, &ebx, &ecx, &edx);
0124     if (eax & XEN_HVM_CPUID_VCPU_ID_PRESENT)
0125         this_cpu_write(xen_vcpu_id, ebx);
0126     else
0127         this_cpu_write(xen_vcpu_id, smp_processor_id());
0128 }
0129
0130 DEFINE_IDTENTRY_SYSVEC(sysvec_xen_hvm_callback)
0131 {
0132     struct pt_regs *old_regs = set_irq_regs(regs);
0133
0134     if (xen_percpu_upcall)
0135         ack_APIC_irq();
0136
0137     inc_irq_stat(irq_hv_callback_count);
0138
0139     xen_hvm_evtchn_do_upcall();
0140
0141     set_irq_regs(old_regs);
0142 }
0143
0144 #ifdef CONFIG_KEXEC_CORE
0145 static void xen_hvm_shutdown(void)
0146 {
0147     native_machine_shutdown();
0148     if (kexec_in_progress)
0149         xen_reboot(SHUTDOWN_soft_reset);
0150 }
0151
0152 static void xen_hvm_crash_shutdown(struct pt_regs *regs)
0153 {
0154     native_machine_crash_shutdown(regs);
0155     xen_reboot(SHUTDOWN_soft_reset);
0156 }
0157 #endif
0158
0159 static int xen_cpu_up_prepare_hvm(unsigned int cpu)
0160 {
0161     int rc = 0;
0162
0163     /*
0164      * This can happen if CPU was offlined earlier and
0165      * offlining timed out in common_cpu_die().
0166      */
0167     if (cpu_report_state(cpu) == CPU_DEAD_FROZEN) {
0168         xen_smp_intr_free(cpu);
0169         xen_uninit_lock_cpu(cpu);
0170     }
0171
0172     if (cpu_acpi_id(cpu) != U32_MAX)
0173         per_cpu(xen_vcpu_id, cpu) = cpu_acpi_id(cpu);
0174     else
0175         per_cpu(xen_vcpu_id, cpu) = cpu;
0176     xen_vcpu_setup(cpu);
0177     if (!xen_have_vector_callback)
0178         return 0;
0179
0180     if (xen_percpu_upcall) {
0181         rc = xen_set_upcall_vector(cpu);
0182         if (rc) {
0183             WARN(1, "HVMOP_set_evtchn_upcall_vector"
0184                  " for CPU %d failed: %d\n", cpu, rc);
0185             return rc;
0186         }
0187     }
0188
0189     if (xen_feature(XENFEAT_hvm_safe_pvclock))
0190         xen_setup_timer(cpu);
0191
0192     rc = xen_smp_intr_init(cpu);
0193     if (rc) {
0194         WARN(1, "xen_smp_intr_init() for CPU %d failed: %d\n",
0195              cpu, rc);
0196     }
0197     return rc;
0198 }
0199
0200 static int xen_cpu_dead_hvm(unsigned int cpu)
0201 {
0202     xen_smp_intr_free(cpu);
0203
0204     if (xen_have_vector_callback && xen_feature(XENFEAT_hvm_safe_pvclock))
0205         xen_teardown_timer(cpu);
0206     return 0;
0207 }
0208
0209 static void __init xen_hvm_guest_init(void)
0210 {
0211     if (xen_pv_domain())
0212         return;
0213
0214     if (IS_ENABLED(CONFIG_XEN_VIRTIO_FORCE_GRANT))
0215         virtio_set_mem_acc_cb(virtio_require_restricted_mem_acc);
0216
0217     init_hvm_pv_info();
0218
0219     reserve_shared_info();
0220     xen_hvm_init_shared_info();
0221
0222     /*
0223      * xen_vcpu is a pointer to the vcpu_info struct in the shared_info
0224      * page, we use it in the event channel upcall and in some pvclock
0225      * related functions.
0226      */
0227     xen_vcpu_info_reset(0);
0228
0229     xen_panic_handler_init();
0230
0231     xen_hvm_smp_init();
0232     WARN_ON(xen_cpuhp_setup(xen_cpu_up_prepare_hvm, xen_cpu_dead_hvm));
0233     xen_unplug_emulated_devices();
0234     x86_init.irqs.intr_init = xen_init_IRQ;
0235     xen_hvm_init_time_ops();
0236     xen_hvm_init_mmu_ops();
0237
0238 #ifdef CONFIG_KEXEC_CORE
0239     machine_ops.shutdown = xen_hvm_shutdown;
0240     machine_ops.crash_shutdown = xen_hvm_crash_shutdown;
0241 #endif
0242 }
0243
0244 static __init int xen_parse_nopv(char *arg)
0245 {
0246     pr_notice("\"xen_nopv\" is deprecated, please use \"nopv\" instead\n");
0247
0248     if (xen_cpuid_base())
0249         nopv = true;
0250     return 0;
0251 }
0252 early_param("xen_nopv", xen_parse_nopv);
0253
0254 static __init int xen_parse_no_vector_callback(char *arg)
0255 {
0256     xen_have_vector_callback = false;
0257     return 0;
0258 }
0259 early_param("xen_no_vector_callback", xen_parse_no_vector_callback);
0260
0261 static __init bool xen_x2apic_available(void)
0262 {
0263     return x2apic_supported();
0264 }
0265
0266 static bool __init msi_ext_dest_id(void)
0267 {
0268        return cpuid_eax(xen_cpuid_base() + 4) & XEN_HVM_CPUID_EXT_DEST_ID;
0269 }
0270
0271 static __init void xen_hvm_guest_late_init(void)
0272 {
0273 #ifdef CONFIG_XEN_PVH
0274     /* Test for PVH domain (PVH boot path taken overrides ACPI flags). */
0275     if (!xen_pvh &&
0276         (x86_platform.legacy.rtc || !x86_platform.legacy.no_vga))
0277         return;
0278
0279     /* PVH detected. */
0280     xen_pvh = true;
0281
0282     if (nopv)
0283         panic("\"nopv\" and \"xen_nopv\" parameters are unsupported in PVH guest.");
0284
0285     /* Make sure we don't fall back to (default) ACPI_IRQ_MODEL_PIC. */
0286     if (!nr_ioapics && acpi_irq_model == ACPI_IRQ_MODEL_PIC)
0287         acpi_irq_model = ACPI_IRQ_MODEL_PLATFORM;
0288
0289     machine_ops.emergency_restart = xen_emergency_restart;
0290     pv_info.name = "Xen PVH";
0291 #endif
0292 }
0293
0294 static uint32_t __init xen_platform_hvm(void)
0295 {
0296     uint32_t xen_domain = xen_cpuid_base();
0297     struct x86_hyper_init *h = &x86_hyper_xen_hvm.init;
0298
0299     if (xen_pv_domain())
0300         return 0;
0301
0302     if (xen_pvh_domain() && nopv) {
0303         /* Guest booting via the Xen-PVH boot entry goes here */
0304         pr_info("\"nopv\" parameter is ignored in PVH guest\n");
0305         nopv = false;
0306     } else if (nopv && xen_domain) {
0307         /*
0308          * Guest booting via normal boot entry (like via grub2) goes
0309          * here.
0310          *
0311          * Use interface functions for bare hardware if nopv,
0312          * xen_hvm_guest_late_init is an exception as we need to
0313          * detect PVH and panic there.
0314          */
0315         h->init_platform = x86_init_noop;
0316         h->x2apic_available = bool_x86_init_noop;
0317         h->init_mem_mapping = x86_init_noop;
0318         h->init_after_bootmem = x86_init_noop;
0319         h->guest_late_init = xen_hvm_guest_late_init;
0320         x86_hyper_xen_hvm.runtime.pin_vcpu = x86_op_int_noop;
0321     }
0322     return xen_domain;
0323 }
0324
0325 struct hypervisor_x86 x86_hyper_xen_hvm __initdata = {
0326     .name                   = "Xen HVM",
0327     .detect                 = xen_platform_hvm,
0328     .type           = X86_HYPER_XEN_HVM,
0329     .init.init_platform     = xen_hvm_guest_init,
0330     .init.x2apic_available  = xen_x2apic_available,
0331     .init.init_mem_mapping  = xen_hvm_init_mem_mapping,
0332     .init.guest_late_init   = xen_hvm_guest_late_init,
0333     .init.msi_ext_dest_id   = msi_ext_dest_id,
0334     .runtime.pin_vcpu       = xen_pin_vcpu,
0335     .ignore_nopv            = true,
0336 };