https://github.com/torvalds/linux
Tip revision: 7d2a07b769330c34b4deabeed939325c77a7ec2f authored by Linus Torvalds on 29 August 2021, 22:04:50 UTC
Linux 5.14
Linux 5.14
Tip revision: 7d2a07b
enlighten_hvm.c
// SPDX-License-Identifier: GPL-2.0
#include <linux/acpi.h>
#include <linux/cpu.h>
#include <linux/kexec.h>
#include <linux/memblock.h>
#include <xen/features.h>
#include <xen/events.h>
#include <xen/interface/memory.h>
#include <asm/cpu.h>
#include <asm/smp.h>
#include <asm/io_apic.h>
#include <asm/reboot.h>
#include <asm/setup.h>
#include <asm/idtentry.h>
#include <asm/hypervisor.h>
#include <asm/e820/api.h>
#include <asm/early_ioremap.h>
#include <asm/xen/cpuid.h>
#include <asm/xen/hypervisor.h>
#include <asm/xen/page.h>
#include "xen-ops.h"
#include "mmu.h"
#include "smp.h"
static unsigned long shared_info_pfn;
void xen_hvm_init_shared_info(void)
{
struct xen_add_to_physmap xatp;
xatp.domid = DOMID_SELF;
xatp.idx = 0;
xatp.space = XENMAPSPACE_shared_info;
xatp.gpfn = shared_info_pfn;
if (HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp))
BUG();
}
static void __init reserve_shared_info(void)
{
u64 pa;
/*
* Search for a free page starting at 4kB physical address.
* Low memory is preferred to avoid an EPT large page split up
* by the mapping.
* Starting below X86_RESERVE_LOW (usually 64kB) is fine as
* the BIOS used for HVM guests is well behaved and won't
* clobber memory other than the first 4kB.
*/
for (pa = PAGE_SIZE;
!e820__mapped_all(pa, pa + PAGE_SIZE, E820_TYPE_RAM) ||
memblock_is_reserved(pa);
pa += PAGE_SIZE)
;
shared_info_pfn = PHYS_PFN(pa);
memblock_reserve(pa, PAGE_SIZE);
HYPERVISOR_shared_info = early_memremap(pa, PAGE_SIZE);
}
static void __init xen_hvm_init_mem_mapping(void)
{
early_memunmap(HYPERVISOR_shared_info, PAGE_SIZE);
HYPERVISOR_shared_info = __va(PFN_PHYS(shared_info_pfn));
/*
* The virtual address of the shared_info page has changed, so
* the vcpu_info pointer for VCPU 0 is now stale.
*
* The prepare_boot_cpu callback will re-initialize it via
* xen_vcpu_setup, but we can't rely on that to be called for
* old Xen versions (xen_have_vector_callback == 0).
*
* It is, in any case, bad to have a stale vcpu_info pointer
* so reset it now.
*/
xen_vcpu_info_reset(0);
}
static void __init init_hvm_pv_info(void)
{
int major, minor;
uint32_t eax, ebx, ecx, edx, base;
base = xen_cpuid_base();
eax = cpuid_eax(base + 1);
major = eax >> 16;
minor = eax & 0xffff;
printk(KERN_INFO "Xen version %d.%d.\n", major, minor);
xen_domain_type = XEN_HVM_DOMAIN;
/* PVH set up hypercall page in xen_prepare_pvh(). */
if (xen_pvh_domain())
pv_info.name = "Xen PVH";
else {
u64 pfn;
uint32_t msr;
pv_info.name = "Xen HVM";
msr = cpuid_ebx(base + 2);
pfn = __pa(hypercall_page);
wrmsr_safe(msr, (u32)pfn, (u32)(pfn >> 32));
}
xen_setup_features();
cpuid(base + 4, &eax, &ebx, &ecx, &edx);
if (eax & XEN_HVM_CPUID_VCPU_ID_PRESENT)
this_cpu_write(xen_vcpu_id, ebx);
else
this_cpu_write(xen_vcpu_id, smp_processor_id());
}
DEFINE_IDTENTRY_SYSVEC(sysvec_xen_hvm_callback)
{
struct pt_regs *old_regs = set_irq_regs(regs);
inc_irq_stat(irq_hv_callback_count);
xen_hvm_evtchn_do_upcall();
set_irq_regs(old_regs);
}
#ifdef CONFIG_KEXEC_CORE
static void xen_hvm_shutdown(void)
{
native_machine_shutdown();
if (kexec_in_progress)
xen_reboot(SHUTDOWN_soft_reset);
}
static void xen_hvm_crash_shutdown(struct pt_regs *regs)
{
native_machine_crash_shutdown(regs);
xen_reboot(SHUTDOWN_soft_reset);
}
#endif
static int xen_cpu_up_prepare_hvm(unsigned int cpu)
{
int rc = 0;
/*
* This can happen if CPU was offlined earlier and
* offlining timed out in common_cpu_die().
*/
if (cpu_report_state(cpu) == CPU_DEAD_FROZEN) {
xen_smp_intr_free(cpu);
xen_uninit_lock_cpu(cpu);
}
if (cpu_acpi_id(cpu) != U32_MAX)
per_cpu(xen_vcpu_id, cpu) = cpu_acpi_id(cpu);
else
per_cpu(xen_vcpu_id, cpu) = cpu;
rc = xen_vcpu_setup(cpu);
if (rc || !xen_have_vector_callback)
return rc;
if (xen_feature(XENFEAT_hvm_safe_pvclock))
xen_setup_timer(cpu);
rc = xen_smp_intr_init(cpu);
if (rc) {
WARN(1, "xen_smp_intr_init() for CPU %d failed: %d\n",
cpu, rc);
}
return rc;
}
static int xen_cpu_dead_hvm(unsigned int cpu)
{
xen_smp_intr_free(cpu);
if (xen_have_vector_callback && xen_feature(XENFEAT_hvm_safe_pvclock))
xen_teardown_timer(cpu);
return 0;
}
static bool no_vector_callback __initdata;
static void __init xen_hvm_guest_init(void)
{
if (xen_pv_domain())
return;
init_hvm_pv_info();
reserve_shared_info();
xen_hvm_init_shared_info();
/*
* xen_vcpu is a pointer to the vcpu_info struct in the shared_info
* page, we use it in the event channel upcall and in some pvclock
* related functions.
*/
xen_vcpu_info_reset(0);
xen_panic_handler_init();
if (!no_vector_callback && xen_feature(XENFEAT_hvm_callback_vector))
xen_have_vector_callback = 1;
xen_hvm_smp_init();
WARN_ON(xen_cpuhp_setup(xen_cpu_up_prepare_hvm, xen_cpu_dead_hvm));
xen_unplug_emulated_devices();
x86_init.irqs.intr_init = xen_init_IRQ;
xen_hvm_init_time_ops();
xen_hvm_init_mmu_ops();
#ifdef CONFIG_KEXEC_CORE
machine_ops.shutdown = xen_hvm_shutdown;
machine_ops.crash_shutdown = xen_hvm_crash_shutdown;
#endif
}
static __init int xen_parse_nopv(char *arg)
{
pr_notice("\"xen_nopv\" is deprecated, please use \"nopv\" instead\n");
if (xen_cpuid_base())
nopv = true;
return 0;
}
early_param("xen_nopv", xen_parse_nopv);
static __init int xen_parse_no_vector_callback(char *arg)
{
no_vector_callback = true;
return 0;
}
early_param("xen_no_vector_callback", xen_parse_no_vector_callback);
bool __init xen_hvm_need_lapic(void)
{
if (xen_pv_domain())
return false;
if (!xen_hvm_domain())
return false;
if (xen_feature(XENFEAT_hvm_pirqs) && xen_have_vector_callback)
return false;
return true;
}
static __init void xen_hvm_guest_late_init(void)
{
#ifdef CONFIG_XEN_PVH
/* Test for PVH domain (PVH boot path taken overrides ACPI flags). */
if (!xen_pvh &&
(x86_platform.legacy.rtc || !x86_platform.legacy.no_vga))
return;
/* PVH detected. */
xen_pvh = true;
if (nopv)
panic("\"nopv\" and \"xen_nopv\" parameters are unsupported in PVH guest.");
/* Make sure we don't fall back to (default) ACPI_IRQ_MODEL_PIC. */
if (!nr_ioapics && acpi_irq_model == ACPI_IRQ_MODEL_PIC)
acpi_irq_model = ACPI_IRQ_MODEL_PLATFORM;
machine_ops.emergency_restart = xen_emergency_restart;
pv_info.name = "Xen PVH";
#endif
}
static uint32_t __init xen_platform_hvm(void)
{
uint32_t xen_domain = xen_cpuid_base();
struct x86_hyper_init *h = &x86_hyper_xen_hvm.init;
if (xen_pv_domain())
return 0;
if (xen_pvh_domain() && nopv) {
/* Guest booting via the Xen-PVH boot entry goes here */
pr_info("\"nopv\" parameter is ignored in PVH guest\n");
nopv = false;
} else if (nopv && xen_domain) {
/*
* Guest booting via normal boot entry (like via grub2) goes
* here.
*
* Use interface functions for bare hardware if nopv,
* xen_hvm_guest_late_init is an exception as we need to
* detect PVH and panic there.
*/
h->init_platform = x86_init_noop;
h->x2apic_available = bool_x86_init_noop;
h->init_mem_mapping = x86_init_noop;
h->init_after_bootmem = x86_init_noop;
h->guest_late_init = xen_hvm_guest_late_init;
x86_hyper_xen_hvm.runtime.pin_vcpu = x86_op_int_noop;
}
return xen_domain;
}
struct hypervisor_x86 x86_hyper_xen_hvm __initdata = {
.name = "Xen HVM",
.detect = xen_platform_hvm,
.type = X86_HYPER_XEN_HVM,
.init.init_platform = xen_hvm_guest_init,
.init.x2apic_available = xen_x2apic_para_available,
.init.init_mem_mapping = xen_hvm_init_mem_mapping,
.init.guest_late_init = xen_hvm_guest_late_init,
.runtime.pin_vcpu = xen_pin_vcpu,
.ignore_nopv = true,
};