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![Juergen Gross](/assets/img/avatar_default.png)
In order to support virtio in Xen guests add a config option XEN_VIRTIO enabling the user to specify whether in all Xen guests virtio should be able to access memory via Xen grant mappings only on the host side. Also set PLATFORM_VIRTIO_RESTRICTED_MEM_ACCESS feature from the guest initialization code on Arm and x86 if CONFIG_XEN_VIRTIO is enabled. Signed-off-by: Juergen Gross <jgross@suse.com> Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com> Reviewed-by: Stefano Stabellini <sstabellini@kernel.org> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Link: https://lore.kernel.org/r/1654197833-25362-5-git-send-email-olekstysh@gmail.com Signed-off-by: Juergen Gross <jgross@suse.com>
322 lines
7.6 KiB
C
322 lines
7.6 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <linux/acpi.h>
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#include <linux/cpu.h>
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#include <linux/kexec.h>
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#include <linux/memblock.h>
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#include <xen/features.h>
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#include <xen/events.h>
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#include <xen/interface/memory.h>
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#include <asm/apic.h>
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#include <asm/cpu.h>
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#include <asm/smp.h>
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#include <asm/io_apic.h>
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#include <asm/reboot.h>
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#include <asm/setup.h>
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#include <asm/idtentry.h>
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#include <asm/hypervisor.h>
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#include <asm/e820/api.h>
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#include <asm/early_ioremap.h>
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#include <asm/xen/cpuid.h>
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#include <asm/xen/hypervisor.h>
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#include <asm/xen/page.h>
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#include "xen-ops.h"
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#include "mmu.h"
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#include "smp.h"
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static unsigned long shared_info_pfn;
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void xen_hvm_init_shared_info(void)
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{
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struct xen_add_to_physmap xatp;
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xatp.domid = DOMID_SELF;
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xatp.idx = 0;
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xatp.space = XENMAPSPACE_shared_info;
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xatp.gpfn = shared_info_pfn;
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if (HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp))
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BUG();
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}
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static void __init reserve_shared_info(void)
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{
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u64 pa;
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/*
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* Search for a free page starting at 4kB physical address.
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* Low memory is preferred to avoid an EPT large page split up
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* by the mapping.
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* Starting below X86_RESERVE_LOW (usually 64kB) is fine as
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* the BIOS used for HVM guests is well behaved and won't
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* clobber memory other than the first 4kB.
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*/
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for (pa = PAGE_SIZE;
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!e820__mapped_all(pa, pa + PAGE_SIZE, E820_TYPE_RAM) ||
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memblock_is_reserved(pa);
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pa += PAGE_SIZE)
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;
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shared_info_pfn = PHYS_PFN(pa);
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memblock_reserve(pa, PAGE_SIZE);
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HYPERVISOR_shared_info = early_memremap(pa, PAGE_SIZE);
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}
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static void __init xen_hvm_init_mem_mapping(void)
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{
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early_memunmap(HYPERVISOR_shared_info, PAGE_SIZE);
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HYPERVISOR_shared_info = __va(PFN_PHYS(shared_info_pfn));
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/*
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* The virtual address of the shared_info page has changed, so
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* the vcpu_info pointer for VCPU 0 is now stale.
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*
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* The prepare_boot_cpu callback will re-initialize it via
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* xen_vcpu_setup, but we can't rely on that to be called for
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* old Xen versions (xen_have_vector_callback == 0).
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*
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* It is, in any case, bad to have a stale vcpu_info pointer
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* so reset it now.
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*/
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xen_vcpu_info_reset(0);
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}
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static void __init init_hvm_pv_info(void)
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{
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int major, minor;
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uint32_t eax, ebx, ecx, edx, base;
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base = xen_cpuid_base();
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eax = cpuid_eax(base + 1);
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major = eax >> 16;
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minor = eax & 0xffff;
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printk(KERN_INFO "Xen version %d.%d.\n", major, minor);
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xen_domain_type = XEN_HVM_DOMAIN;
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/* PVH set up hypercall page in xen_prepare_pvh(). */
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if (xen_pvh_domain())
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pv_info.name = "Xen PVH";
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else {
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u64 pfn;
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uint32_t msr;
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pv_info.name = "Xen HVM";
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msr = cpuid_ebx(base + 2);
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pfn = __pa(hypercall_page);
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wrmsr_safe(msr, (u32)pfn, (u32)(pfn >> 32));
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}
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xen_setup_features();
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cpuid(base + 4, &eax, &ebx, &ecx, &edx);
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if (eax & XEN_HVM_CPUID_VCPU_ID_PRESENT)
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this_cpu_write(xen_vcpu_id, ebx);
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else
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this_cpu_write(xen_vcpu_id, smp_processor_id());
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}
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DEFINE_IDTENTRY_SYSVEC(sysvec_xen_hvm_callback)
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{
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struct pt_regs *old_regs = set_irq_regs(regs);
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inc_irq_stat(irq_hv_callback_count);
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xen_hvm_evtchn_do_upcall();
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set_irq_regs(old_regs);
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}
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#ifdef CONFIG_KEXEC_CORE
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static void xen_hvm_shutdown(void)
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{
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native_machine_shutdown();
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if (kexec_in_progress)
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xen_reboot(SHUTDOWN_soft_reset);
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}
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static void xen_hvm_crash_shutdown(struct pt_regs *regs)
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{
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native_machine_crash_shutdown(regs);
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xen_reboot(SHUTDOWN_soft_reset);
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}
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#endif
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static int xen_cpu_up_prepare_hvm(unsigned int cpu)
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{
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int rc = 0;
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/*
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* This can happen if CPU was offlined earlier and
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* offlining timed out in common_cpu_die().
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*/
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if (cpu_report_state(cpu) == CPU_DEAD_FROZEN) {
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xen_smp_intr_free(cpu);
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xen_uninit_lock_cpu(cpu);
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}
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if (cpu_acpi_id(cpu) != U32_MAX)
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per_cpu(xen_vcpu_id, cpu) = cpu_acpi_id(cpu);
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else
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per_cpu(xen_vcpu_id, cpu) = cpu;
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xen_vcpu_setup(cpu);
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if (!xen_have_vector_callback)
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return 0;
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if (xen_feature(XENFEAT_hvm_safe_pvclock))
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xen_setup_timer(cpu);
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rc = xen_smp_intr_init(cpu);
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if (rc) {
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WARN(1, "xen_smp_intr_init() for CPU %d failed: %d\n",
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cpu, rc);
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}
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return rc;
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}
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static int xen_cpu_dead_hvm(unsigned int cpu)
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{
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xen_smp_intr_free(cpu);
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if (xen_have_vector_callback && xen_feature(XENFEAT_hvm_safe_pvclock))
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xen_teardown_timer(cpu);
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return 0;
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}
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static bool no_vector_callback __initdata;
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static void __init xen_hvm_guest_init(void)
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{
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if (xen_pv_domain())
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return;
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xen_set_restricted_virtio_memory_access();
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init_hvm_pv_info();
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reserve_shared_info();
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xen_hvm_init_shared_info();
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/*
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* xen_vcpu is a pointer to the vcpu_info struct in the shared_info
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* page, we use it in the event channel upcall and in some pvclock
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* related functions.
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*/
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xen_vcpu_info_reset(0);
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xen_panic_handler_init();
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if (!no_vector_callback && xen_feature(XENFEAT_hvm_callback_vector))
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xen_have_vector_callback = 1;
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xen_hvm_smp_init();
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WARN_ON(xen_cpuhp_setup(xen_cpu_up_prepare_hvm, xen_cpu_dead_hvm));
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xen_unplug_emulated_devices();
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x86_init.irqs.intr_init = xen_init_IRQ;
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xen_hvm_init_time_ops();
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xen_hvm_init_mmu_ops();
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#ifdef CONFIG_KEXEC_CORE
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machine_ops.shutdown = xen_hvm_shutdown;
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machine_ops.crash_shutdown = xen_hvm_crash_shutdown;
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#endif
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}
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static __init int xen_parse_nopv(char *arg)
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{
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pr_notice("\"xen_nopv\" is deprecated, please use \"nopv\" instead\n");
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if (xen_cpuid_base())
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nopv = true;
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return 0;
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}
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early_param("xen_nopv", xen_parse_nopv);
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static __init int xen_parse_no_vector_callback(char *arg)
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{
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no_vector_callback = true;
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return 0;
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}
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early_param("xen_no_vector_callback", xen_parse_no_vector_callback);
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static __init bool xen_x2apic_available(void)
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{
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return x2apic_supported();
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}
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static bool __init msi_ext_dest_id(void)
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{
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return cpuid_eax(xen_cpuid_base() + 4) & XEN_HVM_CPUID_EXT_DEST_ID;
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}
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static __init void xen_hvm_guest_late_init(void)
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{
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#ifdef CONFIG_XEN_PVH
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/* Test for PVH domain (PVH boot path taken overrides ACPI flags). */
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if (!xen_pvh &&
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(x86_platform.legacy.rtc || !x86_platform.legacy.no_vga))
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return;
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/* PVH detected. */
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xen_pvh = true;
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if (nopv)
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panic("\"nopv\" and \"xen_nopv\" parameters are unsupported in PVH guest.");
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/* Make sure we don't fall back to (default) ACPI_IRQ_MODEL_PIC. */
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if (!nr_ioapics && acpi_irq_model == ACPI_IRQ_MODEL_PIC)
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acpi_irq_model = ACPI_IRQ_MODEL_PLATFORM;
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machine_ops.emergency_restart = xen_emergency_restart;
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pv_info.name = "Xen PVH";
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#endif
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}
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static uint32_t __init xen_platform_hvm(void)
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{
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uint32_t xen_domain = xen_cpuid_base();
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struct x86_hyper_init *h = &x86_hyper_xen_hvm.init;
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if (xen_pv_domain())
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return 0;
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if (xen_pvh_domain() && nopv) {
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/* Guest booting via the Xen-PVH boot entry goes here */
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pr_info("\"nopv\" parameter is ignored in PVH guest\n");
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nopv = false;
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} else if (nopv && xen_domain) {
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/*
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* Guest booting via normal boot entry (like via grub2) goes
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* here.
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*
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* Use interface functions for bare hardware if nopv,
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* xen_hvm_guest_late_init is an exception as we need to
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* detect PVH and panic there.
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*/
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h->init_platform = x86_init_noop;
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h->x2apic_available = bool_x86_init_noop;
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h->init_mem_mapping = x86_init_noop;
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h->init_after_bootmem = x86_init_noop;
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h->guest_late_init = xen_hvm_guest_late_init;
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x86_hyper_xen_hvm.runtime.pin_vcpu = x86_op_int_noop;
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}
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return xen_domain;
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}
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struct hypervisor_x86 x86_hyper_xen_hvm __initdata = {
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.name = "Xen HVM",
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.detect = xen_platform_hvm,
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.type = X86_HYPER_XEN_HVM,
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.init.init_platform = xen_hvm_guest_init,
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.init.x2apic_available = xen_x2apic_available,
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.init.init_mem_mapping = xen_hvm_init_mem_mapping,
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.init.guest_late_init = xen_hvm_guest_late_init,
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.init.msi_ext_dest_id = msi_ext_dest_id,
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.runtime.pin_vcpu = xen_pin_vcpu,
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.ignore_nopv = true,
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};
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