diff options
Diffstat (limited to 'arch/x86/platform/pvh')
| -rw-r--r-- | arch/x86/platform/pvh/Makefile | 5 | ||||
| -rw-r--r-- | arch/x86/platform/pvh/enlighten.c | 137 | ||||
| -rw-r--r-- | arch/x86/platform/pvh/head.S | 177 |
3 files changed, 319 insertions, 0 deletions
diff --git a/arch/x86/platform/pvh/Makefile b/arch/x86/platform/pvh/Makefile new file mode 100644 index 000000000000..5dec5067c9fb --- /dev/null +++ b/arch/x86/platform/pvh/Makefile @@ -0,0 +1,5 @@ +# SPDX-License-Identifier: GPL-2.0 +OBJECT_FILES_NON_STANDARD_head.o := y + +obj-$(CONFIG_PVH) += enlighten.o +obj-$(CONFIG_PVH) += head.o diff --git a/arch/x86/platform/pvh/enlighten.c b/arch/x86/platform/pvh/enlighten.c new file mode 100644 index 000000000000..62f5c7045944 --- /dev/null +++ b/arch/x86/platform/pvh/enlighten.c @@ -0,0 +1,137 @@ +// SPDX-License-Identifier: GPL-2.0 +#include <linux/acpi.h> + +#include <xen/hvc-console.h> + +#include <asm/io_apic.h> +#include <asm/hypervisor.h> +#include <asm/e820/api.h> +#include <asm/x86_init.h> + +#include <asm/xen/interface.h> + +#include <xen/xen.h> +#include <xen/interface/hvm/start_info.h> + +/* + * PVH variables. + * + * pvh_bootparams and pvh_start_info need to live in the data segment since + * they are used after startup_{32|64}, which clear .bss, are invoked. + */ +struct boot_params pvh_bootparams __attribute__((section(".data"))); +struct hvm_start_info pvh_start_info __attribute__((section(".data"))); + +unsigned int pvh_start_info_sz = sizeof(pvh_start_info); + +static u64 pvh_get_root_pointer(void) +{ + return pvh_start_info.rsdp_paddr; +} + +/* + * Xen guests are able to obtain the memory map from the hypervisor via the + * HYPERVISOR_memory_op hypercall. + * If we are trying to boot a Xen PVH guest, it is expected that the kernel + * will have been configured to provide an override for this routine to do + * just that. + */ +void __init __weak mem_map_via_hcall(struct boot_params *ptr __maybe_unused) +{ + xen_raw_printk("Error: Could not find memory map\n"); + BUG(); +} + +static void __init init_pvh_bootparams(bool xen_guest) +{ + memset(&pvh_bootparams, 0, sizeof(pvh_bootparams)); + + if ((pvh_start_info.version > 0) && (pvh_start_info.memmap_entries)) { + struct hvm_memmap_table_entry *ep; + int i; + + ep = __va(pvh_start_info.memmap_paddr); + pvh_bootparams.e820_entries = pvh_start_info.memmap_entries; + + for (i = 0; i < pvh_bootparams.e820_entries ; i++, ep++) { + pvh_bootparams.e820_table[i].addr = ep->addr; + pvh_bootparams.e820_table[i].size = ep->size; + pvh_bootparams.e820_table[i].type = ep->type; + } + } else if (xen_guest) { + mem_map_via_hcall(&pvh_bootparams); + } else { + /* Non-xen guests are not supported by version 0 */ + BUG(); + } + + if (pvh_bootparams.e820_entries < E820_MAX_ENTRIES_ZEROPAGE - 1) { + pvh_bootparams.e820_table[pvh_bootparams.e820_entries].addr = + ISA_START_ADDRESS; + pvh_bootparams.e820_table[pvh_bootparams.e820_entries].size = + ISA_END_ADDRESS - ISA_START_ADDRESS; + pvh_bootparams.e820_table[pvh_bootparams.e820_entries].type = + E820_TYPE_RESERVED; + pvh_bootparams.e820_entries++; + } else + xen_raw_printk("Warning: Can fit ISA range into e820\n"); + + pvh_bootparams.hdr.cmd_line_ptr = + pvh_start_info.cmdline_paddr; + + /* The first module is always ramdisk. */ + if (pvh_start_info.nr_modules) { + struct hvm_modlist_entry *modaddr = + __va(pvh_start_info.modlist_paddr); + pvh_bootparams.hdr.ramdisk_image = modaddr->paddr; + pvh_bootparams.hdr.ramdisk_size = modaddr->size; + } + + /* + * See Documentation/x86/boot.txt. + * + * Version 2.12 supports Xen entry point but we will use default x86/PC + * environment (i.e. hardware_subarch 0). + */ + pvh_bootparams.hdr.version = (2 << 8) | 12; + pvh_bootparams.hdr.type_of_loader = ((xen_guest ? 0x9 : 0xb) << 4) | 0; + + x86_init.acpi.get_root_pointer = pvh_get_root_pointer; +} + +/* + * If we are trying to boot a Xen PVH guest, it is expected that the kernel + * will have been configured to provide the required override for this routine. + */ +void __init __weak xen_pvh_init(void) +{ + xen_raw_printk("Error: Missing xen PVH initialization\n"); + BUG(); +} + +static void hypervisor_specific_init(bool xen_guest) +{ + if (xen_guest) + xen_pvh_init(); +} + +/* + * This routine (and those that it might call) should not use + * anything that lives in .bss since that segment will be cleared later. + */ +void __init xen_prepare_pvh(void) +{ + + u32 msr = xen_cpuid_base(); + bool xen_guest = !!msr; + + if (pvh_start_info.magic != XEN_HVM_START_MAGIC_VALUE) { + xen_raw_printk("Error: Unexpected magic value (0x%08x)\n", + pvh_start_info.magic); + BUG(); + } + + hypervisor_specific_init(xen_guest); + + init_pvh_bootparams(xen_guest); +} diff --git a/arch/x86/platform/pvh/head.S b/arch/x86/platform/pvh/head.S new file mode 100644 index 000000000000..1f8825bbaffb --- /dev/null +++ b/arch/x86/platform/pvh/head.S @@ -0,0 +1,177 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +/* + * Copyright C 2016, Oracle and/or its affiliates. All rights reserved. + */ + + .code32 + .text +#define _pa(x) ((x) - __START_KERNEL_map) + +#include <linux/elfnote.h> +#include <linux/init.h> +#include <linux/linkage.h> +#include <asm/segment.h> +#include <asm/asm.h> +#include <asm/boot.h> +#include <asm/processor-flags.h> +#include <asm/msr.h> +#include <xen/interface/elfnote.h> + + __HEAD + +/* + * Entry point for PVH guests. + * + * Xen ABI specifies the following register state when we come here: + * + * - `ebx`: contains the physical memory address where the loader has placed + * the boot start info structure. + * - `cr0`: bit 0 (PE) must be set. All the other writeable bits are cleared. + * - `cr4`: all bits are cleared. + * - `cs `: must be a 32-bit read/execute code segment with a base of ‘0’ + * and a limit of ‘0xFFFFFFFF’. The selector value is unspecified. + * - `ds`, `es`: must be a 32-bit read/write data segment with a base of + * ‘0’ and a limit of ‘0xFFFFFFFF’. The selector values are all + * unspecified. + * - `tr`: must be a 32-bit TSS (active) with a base of '0' and a limit + * of '0x67'. + * - `eflags`: bit 17 (VM) must be cleared. Bit 9 (IF) must be cleared. + * Bit 8 (TF) must be cleared. Other bits are all unspecified. + * + * All other processor registers and flag bits are unspecified. The OS is in + * charge of setting up it's own stack, GDT and IDT. + */ + +#define PVH_GDT_ENTRY_CS 1 +#define PVH_GDT_ENTRY_DS 2 +#define PVH_GDT_ENTRY_CANARY 3 +#define PVH_CS_SEL (PVH_GDT_ENTRY_CS * 8) +#define PVH_DS_SEL (PVH_GDT_ENTRY_DS * 8) +#define PVH_CANARY_SEL (PVH_GDT_ENTRY_CANARY * 8) + +ENTRY(pvh_start_xen) + cld + + lgdt (_pa(gdt)) + + mov $PVH_DS_SEL,%eax + mov %eax,%ds + mov %eax,%es + mov %eax,%ss + + /* Stash hvm_start_info. */ + mov $_pa(pvh_start_info), %edi + mov %ebx, %esi + mov _pa(pvh_start_info_sz), %ecx + shr $2,%ecx + rep + movsl + + mov $_pa(early_stack_end), %esp + + /* Enable PAE mode. */ + mov %cr4, %eax + orl $X86_CR4_PAE, %eax + mov %eax, %cr4 + +#ifdef CONFIG_X86_64 + /* Enable Long mode. */ + mov $MSR_EFER, %ecx + rdmsr + btsl $_EFER_LME, %eax + wrmsr + + /* Enable pre-constructed page tables. */ + mov $_pa(init_top_pgt), %eax + mov %eax, %cr3 + mov $(X86_CR0_PG | X86_CR0_PE), %eax + mov %eax, %cr0 + + /* Jump to 64-bit mode. */ + ljmp $PVH_CS_SEL, $_pa(1f) + + /* 64-bit entry point. */ + .code64 +1: + /* Set base address in stack canary descriptor. */ + mov $MSR_GS_BASE,%ecx + mov $_pa(canary), %eax + xor %edx, %edx + wrmsr + + call xen_prepare_pvh + + /* startup_64 expects boot_params in %rsi. */ + mov $_pa(pvh_bootparams), %rsi + mov $_pa(startup_64), %rax + jmp *%rax + +#else /* CONFIG_X86_64 */ + + /* Set base address in stack canary descriptor. */ + movl $_pa(gdt_start),%eax + movl $_pa(canary),%ecx + movw %cx, (PVH_GDT_ENTRY_CANARY * 8) + 2(%eax) + shrl $16, %ecx + movb %cl, (PVH_GDT_ENTRY_CANARY * 8) + 4(%eax) + movb %ch, (PVH_GDT_ENTRY_CANARY * 8) + 7(%eax) + + mov $PVH_CANARY_SEL,%eax + mov %eax,%gs + + call mk_early_pgtbl_32 + + mov $_pa(initial_page_table), %eax + mov %eax, %cr3 + + mov %cr0, %eax + or $(X86_CR0_PG | X86_CR0_PE), %eax + mov %eax, %cr0 + + ljmp $PVH_CS_SEL, $1f +1: + call xen_prepare_pvh + mov $_pa(pvh_bootparams), %esi + + /* startup_32 doesn't expect paging and PAE to be on. */ + ljmp $PVH_CS_SEL, $_pa(2f) +2: + mov %cr0, %eax + and $~X86_CR0_PG, %eax + mov %eax, %cr0 + mov %cr4, %eax + and $~X86_CR4_PAE, %eax + mov %eax, %cr4 + + ljmp $PVH_CS_SEL, $_pa(startup_32) +#endif +END(pvh_start_xen) + + .section ".init.data","aw" + .balign 8 +gdt: + .word gdt_end - gdt_start + .long _pa(gdt_start) + .word 0 +gdt_start: + .quad 0x0000000000000000 /* NULL descriptor */ +#ifdef CONFIG_X86_64 + .quad GDT_ENTRY(0xa09a, 0, 0xfffff) /* PVH_CS_SEL */ +#else + .quad GDT_ENTRY(0xc09a, 0, 0xfffff) /* PVH_CS_SEL */ +#endif + .quad GDT_ENTRY(0xc092, 0, 0xfffff) /* PVH_DS_SEL */ + .quad GDT_ENTRY(0x4090, 0, 0x18) /* PVH_CANARY_SEL */ +gdt_end: + + .balign 16 +canary: + .fill 48, 1, 0 + +early_stack: + .fill BOOT_STACK_SIZE, 1, 0 +early_stack_end: + + ELFNOTE(Xen, XEN_ELFNOTE_PHYS32_ENTRY, + _ASM_PTR (pvh_start_xen - __START_KERNEL_map)) |