/* * X86 specific Hyper-V initialization code. * * Copyright (C) 2016, Microsoft, Inc. * * Author : K. Y. Srinivasan * * This program is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 as published * by the Free Software Foundation. * * This program is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or * NON INFRINGEMENT. See the GNU General Public License for more * details. * */ #include #include #include #include #include #include #include #include #ifdef CONFIG_X86_64 static struct ms_hyperv_tsc_page *tsc_pg; static u64 read_hv_clock_tsc(struct clocksource *arg) { u64 current_tick; if (tsc_pg->tsc_sequence != 0) { /* * Use the tsc page to compute the value. */ while (1) { u64 tmp; u32 sequence = tsc_pg->tsc_sequence; u64 cur_tsc; u64 scale = tsc_pg->tsc_scale; s64 offset = tsc_pg->tsc_offset; rdtscll(cur_tsc); /* current_tick = ((cur_tsc *scale) >> 64) + offset */ asm("mulq %3" : "=d" (current_tick), "=a" (tmp) : "a" (cur_tsc), "r" (scale)); current_tick += offset; if (tsc_pg->tsc_sequence == sequence) return current_tick; if (tsc_pg->tsc_sequence != 0) continue; /* * Fallback using MSR method. */ break; } } rdmsrl(HV_X64_MSR_TIME_REF_COUNT, current_tick); return current_tick; } static struct clocksource hyperv_cs_tsc = { .name = "hyperv_clocksource_tsc_page", .rating = 400, .read = read_hv_clock_tsc, .mask = CLOCKSOURCE_MASK(64), .flags = CLOCK_SOURCE_IS_CONTINUOUS, }; #endif static u64 read_hv_clock_msr(struct clocksource *arg) { u64 current_tick; /* * Read the partition counter to get the current tick count. This count * is set to 0 when the partition is created and is incremented in * 100 nanosecond units. */ rdmsrl(HV_X64_MSR_TIME_REF_COUNT, current_tick); return current_tick; } static struct clocksource hyperv_cs_msr = { .name = "hyperv_clocksource_msr", .rating = 400, .read = read_hv_clock_msr, .mask = CLOCKSOURCE_MASK(64), .flags = CLOCK_SOURCE_IS_CONTINUOUS, }; static void *hypercall_pg; struct clocksource *hyperv_cs; EXPORT_SYMBOL_GPL(hyperv_cs); /* * This function is to be invoked early in the boot sequence after the * hypervisor has been detected. * * 1. Setup the hypercall page. * 2. Register Hyper-V specific clocksource. */ void hyperv_init(void) { u64 guest_id; union hv_x64_msr_hypercall_contents hypercall_msr; if (x86_hyper != &x86_hyper_ms_hyperv) return; /* * Setup the hypercall page and enable hypercalls. * 1. Register the guest ID * 2. Enable the hypercall and register the hypercall page */ guest_id = generate_guest_id(0, LINUX_VERSION_CODE, 0); wrmsrl(HV_X64_MSR_GUEST_OS_ID, guest_id); hypercall_pg = __vmalloc(PAGE_SIZE, GFP_KERNEL, PAGE_KERNEL_RX); if (hypercall_pg == NULL) { wrmsrl(HV_X64_MSR_GUEST_OS_ID, 0); return; } rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64); hypercall_msr.enable = 1; hypercall_msr.guest_physical_address = vmalloc_to_pfn(hypercall_pg); wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64); /* * Register Hyper-V specific clocksource. */ #ifdef CONFIG_X86_64 if (ms_hyperv.features & HV_X64_MSR_REFERENCE_TSC_AVAILABLE) { union hv_x64_msr_hypercall_contents tsc_msr; tsc_pg = __vmalloc(PAGE_SIZE, GFP_KERNEL, PAGE_KERNEL); if (!tsc_pg) goto register_msr_cs; hyperv_cs = &hyperv_cs_tsc; rdmsrl(HV_X64_MSR_REFERENCE_TSC, tsc_msr.as_uint64); tsc_msr.enable = 1; tsc_msr.guest_physical_address = vmalloc_to_pfn(tsc_pg); wrmsrl(HV_X64_MSR_REFERENCE_TSC, tsc_msr.as_uint64); clocksource_register_hz(&hyperv_cs_tsc, NSEC_PER_SEC/100); return; } register_msr_cs: #endif /* * For 32 bit guests just use the MSR based mechanism for reading * the partition counter. */ hyperv_cs = &hyperv_cs_msr; if (ms_hyperv.features & HV_X64_MSR_TIME_REF_COUNT_AVAILABLE) clocksource_register_hz(&hyperv_cs_msr, NSEC_PER_SEC/100); } /* * This routine is called before kexec/kdump, it does the required cleanup. */ void hyperv_cleanup(void) { union hv_x64_msr_hypercall_contents hypercall_msr; /* Reset our OS id */ wrmsrl(HV_X64_MSR_GUEST_OS_ID, 0); /* Reset the hypercall page */ hypercall_msr.as_uint64 = 0; wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64); /* Reset the TSC page */ hypercall_msr.as_uint64 = 0; wrmsrl(HV_X64_MSR_REFERENCE_TSC, hypercall_msr.as_uint64); } EXPORT_SYMBOL_GPL(hyperv_cleanup); /* * hv_do_hypercall- Invoke the specified hypercall */ u64 hv_do_hypercall(u64 control, void *input, void *output) { u64 input_address = (input) ? virt_to_phys(input) : 0; u64 output_address = (output) ? virt_to_phys(output) : 0; #ifdef CONFIG_X86_64 u64 hv_status = 0; if (!hypercall_pg) return (u64)ULLONG_MAX; __asm__ __volatile__("mov %0, %%r8" : : "r" (output_address) : "r8"); __asm__ __volatile__("call *%3" : "=a" (hv_status) : "c" (control), "d" (input_address), "m" (hypercall_pg)); return hv_status; #else u32 control_hi = control >> 32; u32 control_lo = control & 0xFFFFFFFF; u32 hv_status_hi = 1; u32 hv_status_lo = 1; u32 input_address_hi = input_address >> 32; u32 input_address_lo = input_address & 0xFFFFFFFF; u32 output_address_hi = output_address >> 32; u32 output_address_lo = output_address & 0xFFFFFFFF; if (!hypercall_pg) return (u64)ULLONG_MAX; __asm__ __volatile__ ("call *%8" : "=d"(hv_status_hi), "=a"(hv_status_lo) : "d" (control_hi), "a" (control_lo), "b" (input_address_hi), "c" (input_address_lo), "D"(output_address_hi), "S"(output_address_lo), "m" (hypercall_pg)); return hv_status_lo | ((u64)hv_status_hi << 32); #endif /* !x86_64 */ } EXPORT_SYMBOL_GPL(hv_do_hypercall); void hyperv_report_panic(struct pt_regs *regs) { static bool panic_reported; /* * We prefer to report panic on 'die' chain as we have proper * registers to report, but if we miss it (e.g. on BUG()) we need * to report it on 'panic'. */ if (panic_reported) return; panic_reported = true; wrmsrl(HV_X64_MSR_CRASH_P0, regs->ip); wrmsrl(HV_X64_MSR_CRASH_P1, regs->ax); wrmsrl(HV_X64_MSR_CRASH_P2, regs->bx); wrmsrl(HV_X64_MSR_CRASH_P3, regs->cx); wrmsrl(HV_X64_MSR_CRASH_P4, regs->dx); /* * Let Hyper-V know there is crash data available */ wrmsrl(HV_X64_MSR_CRASH_CTL, HV_CRASH_CTL_CRASH_NOTIFY); } EXPORT_SYMBOL_GPL(hyperv_report_panic); bool hv_is_hypercall_page_setup(void) { union hv_x64_msr_hypercall_contents hypercall_msr; /* Check if the hypercall page is setup */ hypercall_msr.as_uint64 = 0; rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64); if (!hypercall_msr.enable) return false; return true; } EXPORT_SYMBOL_GPL(hv_is_hypercall_page_setup);