xref: /openbmc/linux/arch/x86/xen/enlighten_hvm.c (revision 37510dd5)
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 #include "mmu.h"
32 #include "smp.h"
33 
34 static unsigned long shared_info_pfn;
35 
36 __ro_after_init bool xen_percpu_upcall;
37 EXPORT_SYMBOL_GPL(xen_percpu_upcall);
38 
xen_hvm_init_shared_info(void)39 void xen_hvm_init_shared_info(void)
40 {
41 	struct xen_add_to_physmap xatp;
42 
43 	xatp.domid = DOMID_SELF;
44 	xatp.idx = 0;
45 	xatp.space = XENMAPSPACE_shared_info;
46 	xatp.gpfn = shared_info_pfn;
47 	if (HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp))
48 		BUG();
49 }
50 
reserve_shared_info(void)51 static void __init reserve_shared_info(void)
52 {
53 	u64 pa;
54 
55 	/*
56 	 * Search for a free page starting at 4kB physical address.
57 	 * Low memory is preferred to avoid an EPT large page split up
58 	 * by the mapping.
59 	 * Starting below X86_RESERVE_LOW (usually 64kB) is fine as
60 	 * the BIOS used for HVM guests is well behaved and won't
61 	 * clobber memory other than the first 4kB.
62 	 */
63 	for (pa = PAGE_SIZE;
64 	     !e820__mapped_all(pa, pa + PAGE_SIZE, E820_TYPE_RAM) ||
65 	     memblock_is_reserved(pa);
66 	     pa += PAGE_SIZE)
67 		;
68 
69 	shared_info_pfn = PHYS_PFN(pa);
70 
71 	memblock_reserve(pa, PAGE_SIZE);
72 	HYPERVISOR_shared_info = early_memremap(pa, PAGE_SIZE);
73 }
74 
xen_hvm_init_mem_mapping(void)75 static void __init xen_hvm_init_mem_mapping(void)
76 {
77 	early_memunmap(HYPERVISOR_shared_info, PAGE_SIZE);
78 	HYPERVISOR_shared_info = __va(PFN_PHYS(shared_info_pfn));
79 
80 	/*
81 	 * The virtual address of the shared_info page has changed, so
82 	 * the vcpu_info pointer for VCPU 0 is now stale.
83 	 *
84 	 * The prepare_boot_cpu callback will re-initialize it via
85 	 * xen_vcpu_setup, but we can't rely on that to be called for
86 	 * old Xen versions (xen_have_vector_callback == 0).
87 	 *
88 	 * It is, in any case, bad to have a stale vcpu_info pointer
89 	 * so reset it now.
90 	 */
91 	xen_vcpu_info_reset(0);
92 }
93 
init_hvm_pv_info(void)94 static void __init init_hvm_pv_info(void)
95 {
96 	int major, minor;
97 	uint32_t eax, ebx, ecx, edx, base;
98 
99 	base = xen_cpuid_base();
100 	eax = cpuid_eax(base + 1);
101 
102 	major = eax >> 16;
103 	minor = eax & 0xffff;
104 	printk(KERN_INFO "Xen version %d.%d.\n", major, minor);
105 
106 	xen_domain_type = XEN_HVM_DOMAIN;
107 
108 	/* PVH set up hypercall page in xen_prepare_pvh(). */
109 	if (xen_pvh_domain())
110 		pv_info.name = "Xen PVH";
111 	else {
112 		u64 pfn;
113 		uint32_t msr;
114 
115 		pv_info.name = "Xen HVM";
116 		msr = cpuid_ebx(base + 2);
117 		pfn = __pa(hypercall_page);
118 		wrmsr_safe(msr, (u32)pfn, (u32)(pfn >> 32));
119 	}
120 
121 	xen_setup_features();
122 
123 	cpuid(base + 4, &eax, &ebx, &ecx, &edx);
124 	if (eax & XEN_HVM_CPUID_VCPU_ID_PRESENT)
125 		this_cpu_write(xen_vcpu_id, ebx);
126 	else
127 		this_cpu_write(xen_vcpu_id, smp_processor_id());
128 }
129 
DEFINE_IDTENTRY_SYSVEC(sysvec_xen_hvm_callback)130 DEFINE_IDTENTRY_SYSVEC(sysvec_xen_hvm_callback)
131 {
132 	struct pt_regs *old_regs = set_irq_regs(regs);
133 
134 	if (xen_percpu_upcall)
135 		apic_eoi();
136 
137 	inc_irq_stat(irq_hv_callback_count);
138 
139 	xen_evtchn_do_upcall();
140 
141 	set_irq_regs(old_regs);
142 }
143 
144 #ifdef CONFIG_KEXEC_CORE
xen_hvm_shutdown(void)145 static void xen_hvm_shutdown(void)
146 {
147 	native_machine_shutdown();
148 	if (kexec_in_progress)
149 		xen_reboot(SHUTDOWN_soft_reset);
150 }
151 
xen_hvm_crash_shutdown(struct pt_regs * regs)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 
xen_cpu_up_prepare_hvm(unsigned int cpu)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) != U32_MAX)
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 
xen_cpu_dead_hvm(unsigned int cpu)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 
xen_hvm_guest_init(void)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 	machine_ops.crash_shutdown = xen_hvm_crash_shutdown;
240 #endif
241 }
242 
xen_parse_nopv(char * arg)243 static __init int xen_parse_nopv(char *arg)
244 {
245 	pr_notice("\"xen_nopv\" is deprecated, please use \"nopv\" instead\n");
246 
247 	if (xen_cpuid_base())
248 		nopv = true;
249 	return 0;
250 }
251 early_param("xen_nopv", xen_parse_nopv);
252 
xen_parse_no_vector_callback(char * arg)253 static __init int xen_parse_no_vector_callback(char *arg)
254 {
255 	xen_have_vector_callback = false;
256 	return 0;
257 }
258 early_param("xen_no_vector_callback", xen_parse_no_vector_callback);
259 
xen_x2apic_available(void)260 static __init bool xen_x2apic_available(void)
261 {
262 	return x2apic_supported();
263 }
264 
msi_ext_dest_id(void)265 static bool __init msi_ext_dest_id(void)
266 {
267        return cpuid_eax(xen_cpuid_base() + 4) & XEN_HVM_CPUID_EXT_DEST_ID;
268 }
269 
xen_hvm_guest_late_init(void)270 static __init void xen_hvm_guest_late_init(void)
271 {
272 #ifdef CONFIG_XEN_PVH
273 	/* Test for PVH domain (PVH boot path taken overrides ACPI flags). */
274 	if (!xen_pvh &&
275 	    (x86_platform.legacy.rtc || !x86_platform.legacy.no_vga))
276 		return;
277 
278 	/* PVH detected. */
279 	xen_pvh = true;
280 
281 	if (nopv)
282 		panic("\"nopv\" and \"xen_nopv\" parameters are unsupported in PVH guest.");
283 
284 	/* Make sure we don't fall back to (default) ACPI_IRQ_MODEL_PIC. */
285 	if (!nr_ioapics && acpi_irq_model == ACPI_IRQ_MODEL_PIC)
286 		acpi_irq_model = ACPI_IRQ_MODEL_PLATFORM;
287 
288 	machine_ops.emergency_restart = xen_emergency_restart;
289 	pv_info.name = "Xen PVH";
290 #endif
291 }
292 
xen_platform_hvm(void)293 static uint32_t __init xen_platform_hvm(void)
294 {
295 	uint32_t xen_domain = xen_cpuid_base();
296 	struct x86_hyper_init *h = &x86_hyper_xen_hvm.init;
297 
298 	if (xen_pv_domain())
299 		return 0;
300 
301 	if (xen_pvh_domain() && nopv) {
302 		/* Guest booting via the Xen-PVH boot entry goes here */
303 		pr_info("\"nopv\" parameter is ignored in PVH guest\n");
304 		nopv = false;
305 	} else if (nopv && xen_domain) {
306 		/*
307 		 * Guest booting via normal boot entry (like via grub2) goes
308 		 * here.
309 		 *
310 		 * Use interface functions for bare hardware if nopv,
311 		 * xen_hvm_guest_late_init is an exception as we need to
312 		 * detect PVH and panic there.
313 		 */
314 		h->init_platform = x86_init_noop;
315 		h->x2apic_available = bool_x86_init_noop;
316 		h->init_mem_mapping = x86_init_noop;
317 		h->init_after_bootmem = x86_init_noop;
318 		h->guest_late_init = xen_hvm_guest_late_init;
319 		x86_hyper_xen_hvm.runtime.pin_vcpu = x86_op_int_noop;
320 	}
321 	return xen_domain;
322 }
323 
324 struct hypervisor_x86 x86_hyper_xen_hvm __initdata = {
325 	.name                   = "Xen HVM",
326 	.detect                 = xen_platform_hvm,
327 	.type			= X86_HYPER_XEN_HVM,
328 	.init.init_platform     = xen_hvm_guest_init,
329 	.init.x2apic_available  = xen_x2apic_available,
330 	.init.init_mem_mapping	= xen_hvm_init_mem_mapping,
331 	.init.guest_late_init	= xen_hvm_guest_late_init,
332 	.init.msi_ext_dest_id   = msi_ext_dest_id,
333 	.runtime.pin_vcpu       = xen_pin_vcpu,
334 	.ignore_nopv            = true,
335 };
336