diff options
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/Kbuild | 3 | ||||
| -rw-r--r-- | arch/x86/Kconfig | 2 | ||||
| -rw-r--r-- | arch/x86/include/asm/lguest.h | 91 | ||||
| -rw-r--r-- | arch/x86/include/asm/lguest_hcall.h | 74 | ||||
| -rw-r--r-- | arch/x86/include/asm/processor.h | 2 | ||||
| -rw-r--r-- | arch/x86/include/uapi/asm/bootparam.h | 2 | ||||
| -rw-r--r-- | arch/x86/kernel/asm-offsets_32.c | 20 | ||||
| -rw-r--r-- | arch/x86/kernel/head_32.S | 2 | ||||
| -rw-r--r-- | arch/x86/kernel/platform-quirks.c | 1 | ||||
| -rw-r--r-- | arch/x86/kvm/Kconfig | 1 | ||||
| -rw-r--r-- | arch/x86/lguest/Kconfig | 14 | ||||
| -rw-r--r-- | arch/x86/lguest/Makefile | 2 | ||||
| -rw-r--r-- | arch/x86/lguest/boot.c | 1558 | ||||
| -rw-r--r-- | arch/x86/lguest/head_32.S | 192 |
14 files changed, 2 insertions, 1962 deletions
diff --git a/arch/x86/Kbuild b/arch/x86/Kbuild index 586b786b3edf..f65a804b86f0 100644 --- a/arch/x86/Kbuild +++ b/arch/x86/Kbuild @@ -10,9 +10,6 @@ obj-$(CONFIG_XEN) += xen/ # Hyper-V paravirtualization support obj-$(CONFIG_HYPERVISOR_GUEST) += hyperv/ -# lguest paravirtualization support -obj-$(CONFIG_LGUEST_GUEST) += lguest/ - obj-y += realmode/ obj-y += kernel/ obj-y += mm/ diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 9b302121584d..651021713385 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -777,8 +777,6 @@ config KVM_DEBUG_FS Statistics are displayed in debugfs filesystem. Enabling this option may incur significant overhead. -source "arch/x86/lguest/Kconfig" - config PARAVIRT_TIME_ACCOUNTING bool "Paravirtual steal time accounting" depends on PARAVIRT diff --git a/arch/x86/include/asm/lguest.h b/arch/x86/include/asm/lguest.h deleted file mode 100644 index 73d0c9b92087..000000000000 --- a/arch/x86/include/asm/lguest.h +++ /dev/null @@ -1,91 +0,0 @@ -#ifndef _ASM_X86_LGUEST_H -#define _ASM_X86_LGUEST_H - -#define GDT_ENTRY_LGUEST_CS 10 -#define GDT_ENTRY_LGUEST_DS 11 -#define LGUEST_CS (GDT_ENTRY_LGUEST_CS * 8) -#define LGUEST_DS (GDT_ENTRY_LGUEST_DS * 8) - -#ifndef __ASSEMBLY__ -#include <asm/desc.h> - -#define GUEST_PL 1 - -/* Page for Switcher text itself, then two pages per cpu */ -#define SWITCHER_TEXT_PAGES (1) -#define SWITCHER_STACK_PAGES (2 * nr_cpu_ids) -#define TOTAL_SWITCHER_PAGES (SWITCHER_TEXT_PAGES + SWITCHER_STACK_PAGES) - -/* Where we map the Switcher, in both Host and Guest. */ -extern unsigned long switcher_addr; - -/* Found in switcher.S */ -extern unsigned long default_idt_entries[]; - -/* Declarations for definitions in arch/x86/lguest/head_32.S */ -extern char lguest_noirq_iret[]; -extern const char lgstart_cli[], lgend_cli[]; -extern const char lgstart_pushf[], lgend_pushf[]; - -extern void lguest_iret(void); -extern void lguest_init(void); - -struct lguest_regs { - /* Manually saved part. */ - unsigned long eax, ebx, ecx, edx; - unsigned long esi, edi, ebp; - unsigned long gs; - unsigned long fs, ds, es; - unsigned long trapnum, errcode; - /* Trap pushed part */ - unsigned long eip; - unsigned long cs; - unsigned long eflags; - unsigned long esp; - unsigned long ss; -}; - -/* This is a guest-specific page (mapped ro) into the guest. */ -struct lguest_ro_state { - /* Host information we need to restore when we switch back. */ - u32 host_cr3; - struct desc_ptr host_idt_desc; - struct desc_ptr host_gdt_desc; - u32 host_sp; - - /* Fields which are used when guest is running. */ - struct desc_ptr guest_idt_desc; - struct desc_ptr guest_gdt_desc; - struct x86_hw_tss guest_tss; - struct desc_struct guest_idt[IDT_ENTRIES]; - struct desc_struct guest_gdt[GDT_ENTRIES]; -}; - -struct lg_cpu_arch { - /* The GDT entries copied into lguest_ro_state when running. */ - struct desc_struct gdt[GDT_ENTRIES]; - - /* The IDT entries: some copied into lguest_ro_state when running. */ - struct desc_struct idt[IDT_ENTRIES]; - - /* The address of the last guest-visible pagefault (ie. cr2). */ - unsigned long last_pagefault; -}; - -static inline void lguest_set_ts(void) -{ - u32 cr0; - - cr0 = read_cr0(); - if (!(cr0 & 8)) - write_cr0(cr0 | 8); -} - -/* Full 4G segment descriptors, suitable for CS and DS. */ -#define FULL_EXEC_SEGMENT \ - ((struct desc_struct)GDT_ENTRY_INIT(0xc09b, 0, 0xfffff)) -#define FULL_SEGMENT ((struct desc_struct)GDT_ENTRY_INIT(0xc093, 0, 0xfffff)) - -#endif /* __ASSEMBLY__ */ - -#endif /* _ASM_X86_LGUEST_H */ diff --git a/arch/x86/include/asm/lguest_hcall.h b/arch/x86/include/asm/lguest_hcall.h deleted file mode 100644 index 6c119cfae218..000000000000 --- a/arch/x86/include/asm/lguest_hcall.h +++ /dev/null @@ -1,74 +0,0 @@ -/* Architecture specific portion of the lguest hypercalls */ -#ifndef _ASM_X86_LGUEST_HCALL_H -#define _ASM_X86_LGUEST_HCALL_H - -#define LHCALL_FLUSH_ASYNC 0 -#define LHCALL_LGUEST_INIT 1 -#define LHCALL_SHUTDOWN 2 -#define LHCALL_NEW_PGTABLE 4 -#define LHCALL_FLUSH_TLB 5 -#define LHCALL_LOAD_IDT_ENTRY 6 -#define LHCALL_SET_STACK 7 -#define LHCALL_SET_CLOCKEVENT 9 -#define LHCALL_HALT 10 -#define LHCALL_SET_PMD 13 -#define LHCALL_SET_PTE 14 -#define LHCALL_SET_PGD 15 -#define LHCALL_LOAD_TLS 16 -#define LHCALL_LOAD_GDT_ENTRY 18 -#define LHCALL_SEND_INTERRUPTS 19 - -#define LGUEST_TRAP_ENTRY 0x1F - -/* Argument number 3 to LHCALL_LGUEST_SHUTDOWN */ -#define LGUEST_SHUTDOWN_POWEROFF 1 -#define LGUEST_SHUTDOWN_RESTART 2 - -#ifndef __ASSEMBLY__ -#include <asm/hw_irq.h> - -/*G:030 - * But first, how does our Guest contact the Host to ask for privileged - * operations? There are two ways: the direct way is to make a "hypercall", - * to make requests of the Host Itself. - * - * Our hypercall mechanism uses the highest unused trap code (traps 32 and - * above are used by real hardware interrupts). Seventeen hypercalls are - * available: the hypercall number is put in the %eax register, and the - * arguments (when required) are placed in %ebx, %ecx, %edx and %esi. - * If a return value makes sense, it's returned in %eax. - * - * Grossly invalid calls result in Sudden Death at the hands of the vengeful - * Host, rather than returning failure. This reflects Winston Churchill's - * definition of a gentleman: "someone who is only rude intentionally". - */ -static inline unsigned long -hcall(unsigned long call, - unsigned long arg1, unsigned long arg2, unsigned long arg3, - unsigned long arg4) -{ - /* "int" is the Intel instruction to trigger a trap. */ - asm volatile("int $" __stringify(LGUEST_TRAP_ENTRY) - /* The call in %eax (aka "a") might be overwritten */ - : "=a"(call) - /* The arguments are in %eax, %ebx, %ecx, %edx & %esi */ - : "a"(call), "b"(arg1), "c"(arg2), "d"(arg3), "S"(arg4) - /* "memory" means this might write somewhere in memory. - * This isn't true for all calls, but it's safe to tell - * gcc that it might happen so it doesn't get clever. */ - : "memory"); - return call; -} -/*:*/ - -/* Can't use our min() macro here: needs to be a constant */ -#define LGUEST_IRQS (NR_IRQS < 32 ? NR_IRQS: 32) - -#define LHCALL_RING_SIZE 64 -struct hcall_args { - /* These map directly onto eax/ebx/ecx/edx/esi in struct lguest_regs */ - unsigned long arg0, arg1, arg2, arg3, arg4; -}; - -#endif /* !__ASSEMBLY__ */ -#endif /* _ASM_X86_LGUEST_HCALL_H */ diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h index 0b03d655db7c..abc99b9c7ffd 100644 --- a/arch/x86/include/asm/processor.h +++ b/arch/x86/include/asm/processor.h @@ -662,7 +662,7 @@ static inline void sync_core(void) * In case NMI unmasking or performance ever becomes a problem, * the next best option appears to be MOV-to-CR2 and an * unconditional jump. That sequence also works on all CPUs, - * but it will fault at CPL3 (i.e. Xen PV and lguest). + * but it will fault at CPL3 (i.e. Xen PV). * * CPUID is the conventional way, but it's nasty: it doesn't * exist on some 486-like CPUs, and it usually exits to a diff --git a/arch/x86/include/uapi/asm/bootparam.h b/arch/x86/include/uapi/asm/bootparam.h index ddef37b16af2..66b8f93333d1 100644 --- a/arch/x86/include/uapi/asm/bootparam.h +++ b/arch/x86/include/uapi/asm/bootparam.h @@ -201,7 +201,7 @@ struct boot_params { * * @X86_SUBARCH_PC: Should be used if the hardware is enumerable using standard * PC mechanisms (PCI, ACPI) and doesn't need a special boot flow. - * @X86_SUBARCH_LGUEST: Used for x86 hypervisor demo, lguest + * @X86_SUBARCH_LGUEST: Used for x86 hypervisor demo, lguest, deprecated * @X86_SUBARCH_XEN: Used for Xen guest types which follow the PV boot path, * which start at asm startup_xen() entry point and later jump to the C * xen_start_kernel() entry point. Both domU and dom0 type of guests are diff --git a/arch/x86/kernel/asm-offsets_32.c b/arch/x86/kernel/asm-offsets_32.c index 880aa093268d..710edab9e644 100644 --- a/arch/x86/kernel/asm-offsets_32.c +++ b/arch/x86/kernel/asm-offsets_32.c @@ -4,9 +4,6 @@ #include <asm/ucontext.h> -#include <linux/lguest.h> -#include "../../../drivers/lguest/lg.h" - #define __SYSCALL_I386(nr, sym, qual) [nr] = 1, static char syscalls[] = { #include <asm/syscalls_32.h> @@ -62,23 +59,6 @@ void foo(void) OFFSET(stack_canary_offset, stack_canary, canary); #endif -#if defined(CONFIG_LGUEST) || defined(CONFIG_LGUEST_GUEST) || defined(CONFIG_LGUEST_MODULE) - BLANK(); - OFFSET(LGUEST_DATA_irq_enabled, lguest_data, irq_enabled); - OFFSET(LGUEST_DATA_irq_pending, lguest_data, irq_pending); - - BLANK(); - OFFSET(LGUEST_PAGES_host_gdt_desc, lguest_pages, state.host_gdt_desc); - OFFSET(LGUEST_PAGES_host_idt_desc, lguest_pages, state.host_idt_desc); - OFFSET(LGUEST_PAGES_host_cr3, lguest_pages, state.host_cr3); - OFFSET(LGUEST_PAGES_host_sp, lguest_pages, state.host_sp); - OFFSET(LGUEST_PAGES_guest_gdt_desc, lguest_pages,state.guest_gdt_desc); - OFFSET(LGUEST_PAGES_guest_idt_desc, lguest_pages,state.guest_idt_desc); - OFFSET(LGUEST_PAGES_guest_gdt, lguest_pages, state.guest_gdt); - OFFSET(LGUEST_PAGES_regs_trapnum, lguest_pages, regs.trapnum); - OFFSET(LGUEST_PAGES_regs_errcode, lguest_pages, regs.errcode); - OFFSET(LGUEST_PAGES_regs, lguest_pages, regs); -#endif BLANK(); DEFINE(__NR_syscall_max, sizeof(syscalls) - 1); DEFINE(NR_syscalls, sizeof(syscalls)); diff --git a/arch/x86/kernel/head_32.S b/arch/x86/kernel/head_32.S index 0332664eb158..29da9599fec0 100644 --- a/arch/x86/kernel/head_32.S +++ b/arch/x86/kernel/head_32.S @@ -155,7 +155,6 @@ ENTRY(startup_32) jmp *%eax .Lbad_subarch: -WEAK(lguest_entry) WEAK(xen_entry) /* Unknown implementation; there's really nothing we can do at this point. */ @@ -165,7 +164,6 @@ WEAK(xen_entry) subarch_entries: .long .Ldefault_entry /* normal x86/PC */ - .long lguest_entry /* lguest hypervisor */ .long xen_entry /* Xen hypervisor */ .long .Ldefault_entry /* Moorestown MID */ num_subarch_entries = (. - subarch_entries) / 4 diff --git a/arch/x86/kernel/platform-quirks.c b/arch/x86/kernel/platform-quirks.c index 91271122f0df..502a77d0adb0 100644 --- a/arch/x86/kernel/platform-quirks.c +++ b/arch/x86/kernel/platform-quirks.c @@ -16,7 +16,6 @@ void __init x86_early_init_platform_quirks(void) x86_platform.legacy.reserve_bios_regions = 1; break; case X86_SUBARCH_XEN: - case X86_SUBARCH_LGUEST: x86_platform.legacy.devices.pnpbios = 0; x86_platform.legacy.rtc = 0; break; diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig index 2688c7dc5323..3ea624452f93 100644 --- a/arch/x86/kvm/Kconfig +++ b/arch/x86/kvm/Kconfig @@ -89,6 +89,5 @@ config KVM_MMU_AUDIT # OK, it's a little counter-intuitive to do this, but it puts it neatly under # the virtualization menu. source drivers/vhost/Kconfig -source drivers/lguest/Kconfig endif # VIRTUALIZATION diff --git a/arch/x86/lguest/Kconfig b/arch/x86/lguest/Kconfig deleted file mode 100644 index 08f41caada45..000000000000 --- a/arch/x86/lguest/Kconfig +++ /dev/null @@ -1,14 +0,0 @@ -config LGUEST_GUEST - bool "Lguest guest support" - depends on X86_32 && PARAVIRT && PCI - select TTY - select VIRTUALIZATION - select VIRTIO - select VIRTIO_CONSOLE - help - Lguest is a tiny in-kernel hypervisor. Selecting this will - allow your kernel to boot under lguest. This option will increase - your kernel size by about 10k. If in doubt, say N. - - If you say Y here, make sure you say Y (or M) to the virtio block - and net drivers which lguest needs. diff --git a/arch/x86/lguest/Makefile b/arch/x86/lguest/Makefile deleted file mode 100644 index 8f38d577a2fa..000000000000 --- a/arch/x86/lguest/Makefile +++ /dev/null @@ -1,2 +0,0 @@ -obj-y := head_32.o boot.o -CFLAGS_boot.o := $(call cc-option, -fno-stack-protector) diff --git a/arch/x86/lguest/boot.c b/arch/x86/lguest/boot.c deleted file mode 100644 index 99472698c931..000000000000 --- a/arch/x86/lguest/boot.c +++ /dev/null @@ -1,1558 +0,0 @@ -/*P:010 - * A hypervisor allows multiple Operating Systems to run on a single machine. - * To quote David Wheeler: "Any problem in computer science can be solved with - * another layer of indirection." - * - * We keep things simple in two ways. First, we start with a normal Linux - * kernel and insert a module (lg.ko) which allows us to run other Linux - * kernels the same way we'd run processes. We call the first kernel the Host, - * and the others the Guests. The program which sets up and configures Guests - * (such as the example in tools/lguest/lguest.c) is called the Launcher. - * - * Secondly, we only run specially modified Guests, not normal kernels: setting - * CONFIG_LGUEST_GUEST to "y" compiles this file into the kernel so it knows - * how to be a Guest at boot time. This means that you can use the same kernel - * you boot normally (ie. as a Host) as a Guest. - * - * These Guests know that they cannot do privileged operations, such as disable - * interrupts, and that they have to ask the Host to do such things explicitly. - * This file consists of all the replacements for such low-level native - * hardware operations: these special Guest versions call the Host. - * - * So how does the kernel know it's a Guest? We'll see that later, but let's - * just say that we end up here where we replace the native functions various - * "paravirt" structures with our Guest versions, then boot like normal. -:*/ - -/* - * Copyright (C) 2006, Rusty Russell <rusty@rustcorp.com.au> IBM Corporation. - * - * This program is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License as published by - * the Free Software Foundation; either version 2 of the License, or - * (at your option) any later version. - * - * 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. - * - * You should have received a copy of the GNU General Public License - * along with this program; if not, write to the Free Software - * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. - */ -#include <linux/kernel.h> -#include <linux/start_kernel.h> -#include <linux/string.h> -#include <linux/console.h> -#include <linux/screen_info.h> -#include <linux/irq.h> -#include <linux/interrupt.h> -#include <linux/clocksource.h> -#include <linux/clockchips.h> -#include <linux/lguest.h> -#include <linux/lguest_launcher.h> -#include <linux/virtio_console.h> -#include <linux/pm.h> -#include <linux/export.h> -#include <linux/pci.h> -#include <linux/virtio_pci.h> -#include <asm/acpi.h> -#include <asm/apic.h> -#include <asm/lguest.h> -#include <asm/paravirt.h> -#include <asm/param.h> -#include <asm/page.h> -#include <asm/pgtable.h> -#include <asm/desc.h> -#include <asm/setup.h> -#include <asm/e820/api.h> -#include <asm/mce.h> -#include <asm/io.h> -#include <asm/fpu/api.h> -#include <asm/stackprotector.h> -#include <asm/reboot.h> /* for struct machine_ops */ -#include <asm/kvm_para.h> -#include <asm/pci_x86.h> -#include <asm/pci-direct.h> - -/*G:010 - * Welcome to the Guest! - * - * The Guest in our tale is a simple creature: identical to the Host but - * behaving in simplified but equivalent ways. In particular, the Guest is the - * same kernel as the Host (or at least, built from the same source code). -:*/ - -struct lguest_data lguest_data = { - .hcall_status = { [0 ... LHCALL_RING_SIZE-1] = 0xFF }, - .noirq_iret = (u32)lguest_noirq_iret, - .kernel_address = PAGE_OFFSET, - .blocked_interrupts = { 1 }, /* Block timer interrupts */ - .syscall_vec = IA32_SYSCALL_VECTOR, -}; - -/*G:037 - * async_hcall() is pretty simple: I'm quite proud of it really. We have a - * ring buffer of stored hypercalls which the Host will run though next time we - * do a normal hypercall. Each entry in the ring has 5 slots for the hypercall - * arguments, and a "hcall_status" word which is 0 if the call is ready to go, - * and 255 once the Host has finished with it. - * - * If we come around to a slot which hasn't been finished, then the table is - * full and we just make the hypercall directly. This has the nice side - * effect of causing the Host to run all the stored calls in the ring buffer - * which empties it for next time! - */ -static void async_hcall(unsigned long call, unsigned long arg1, - unsigned long arg2, unsigned long arg3, - unsigned long arg4) -{ - /* Note: This code assumes we're uniprocessor. */ - static unsigned int next_call; - unsigned long flags; - - /* - * Disable interrupts if not already disabled: we don't want an - * interrupt handler making a hypercall while we're already doing - * one! - */ - local_irq_save(flags); - if (lguest_data.hcall_status[next_call] != 0xFF) { - /* Table full, so do normal hcall which will flush table. */ - hcall(call, arg1, arg2, arg3, arg4); - } else { - lguest_data.hcalls[next_call].arg0 = call; - lguest_data.hcalls[next_call].arg1 = arg1; - lguest_data.hcalls[next_call].arg2 = arg2; - lguest_data.hcalls[next_call].arg3 = arg3; - lguest_data.hcalls[next_call].arg4 = arg4; - /* Arguments must all be written before we mark it to go */ - wmb(); - lguest_data.hcall_status[next_call] = 0; - if (++next_call == LHCALL_RING_SIZE) - next_call = 0; - } - local_irq_restore(flags); -} - -/*G:035 - * Notice the lazy_hcall() above, rather than hcall(). This is our first real - * optimization trick! - * - * When lazy_mode is set, it means we're allowed to defer all hypercalls and do - * them as a batch when lazy_mode is eventually turned off. Because hypercalls - * are reasonably expensive, batching them up makes sense. For example, a - * large munmap might update dozens of page table entries: that code calls - * paravirt_enter_lazy_mmu(), does the dozen updates, then calls - * lguest_leave_lazy_mode(). - * - * So, when we're in lazy mode, we call async_hcall() to store the call for - * future processing: - */ -static void lazy_hcall1(unsigned long call, unsigned long arg1) -{ - if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE) - hcall(call, arg1, 0, 0, 0); - else - async_hcall(call, arg1, 0, 0, 0); -} - -/* You can imagine what lazy_hcall2, 3 and 4 look like. :*/ -static void lazy_hcall2(unsigned long call, - unsigned long arg1, - unsigned long arg2) -{ - if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE) - hcall(call, arg1, arg2, 0, 0); - else - async_hcall(call, arg1, arg2, 0, 0); -} - -static void lazy_hcall3(unsigned long call, - unsigned long arg1, - unsigned long arg2, - unsigned long arg3) -{ - if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE) - hcall(call, arg1, arg2, arg3, 0); - else - async_hcall(call, arg1, arg2, arg3, 0); -} - -#ifdef CONFIG_X86_PAE -static void lazy_hcall4(unsigned long call, - unsigned long arg1, - unsigned long arg2, - unsigned long arg3, - unsigned long arg4) -{ - if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE) - hcall(call, arg1, arg2, arg3, arg4); - else - async_hcall(call, arg1, arg2, arg3, arg4); -} -#endif - -/*G:036 - * When lazy mode is turned off, we issue the do-nothing hypercall to - * flush any stored calls, and call the generic helper to reset the - * per-cpu lazy mode variable. - */ -static void lguest_leave_lazy_mmu_mode(void) -{ - hcall(LHCALL_FLUSH_ASYNC, 0, 0, 0, 0); - paravirt_leave_lazy_mmu(); -} - -/* - * We also catch the end of context switch; we enter lazy mode for much of - * that too, so again we need to flush here. - * - * (Technically, this is lazy CPU mode, and normally we're in lazy MMU - * mode, but unlike Xen, lguest doesn't care about the difference). - */ -static void lguest_end_context_switch(struct task_struct *next) -{ - hcall(LHCALL_FLUSH_ASYNC, 0, 0, 0, 0); - paravirt_end_context_switch(next); -} - -/*G:032 - * After that diversion we return to our first native-instruction - * replacements: four functions for interrupt control. - * - * The simplest way of implementing these would be to have "turn interrupts - * off" and "turn interrupts on" hypercalls. Unfortunately, this is too slow: - * these are by far the most commonly called functions of those we override. - * - * So instead we keep an "irq_enabled" field inside our "struct lguest_data", - * which the Guest can update with a single instruction. The Host knows to - * check there before it tries to deliver an interrupt. - */ - -/* - * save_flags() is expected to return the processor state (ie. "flags"). The - * flags word contains all kind of stuff, but in practice Linux only cares - * about the interrupt flag. Our "save_flags()" just returns that. - */ -asmlinkage __visible unsigned long lguest_save_fl(void) -{ - return lguest_data.irq_enabled; -} - -/* Interrupts go off... */ -asmlinkage __visible void lguest_irq_disable(void) -{ - lguest_data.irq_enabled = 0; -} - -/* - * Let's pause a moment. Remember how I said these are called so often? - * Jeremy Fitzhardinge optimized them so hard early in 2009 that he had to - * break some rules. In particular, these functions are assumed to save their - * own registers if they need to: normal C functions assume they can trash the - * eax register. To use normal C functions, we use - * PV_CALLEE_SAVE_REGS_THUNK(), which pushes %eax onto the stack, calls the - * C function, then restores it. - */ -PV_CALLEE_SAVE_REGS_THUNK(lguest_save_fl); -PV_CALLEE_SAVE_REGS_THUNK(lguest_irq_disable); -/*:*/ - -/* These are in head_32.S */ -extern void lg_irq_enable(void); -extern void lg_restore_fl(unsigned long flags); - -/*M:003 - * We could be more efficient in our checking of outstanding interrupts, rather - * than using a branch. One way would be to put the "irq_enabled" field in a - * page by itself, and have the Host write-protect it when an interrupt comes - * in when irqs are disabled. There will then be a page fault as soon as - * interrupts are re-enabled. - * - * A better method is to implement soft interrupt disable generally for x86: - * instead of disabling interrupts, we set a flag. If an interrupt does come - * in, we then disable them for real. This is uncommon, so we could simply use - * a hypercall for interrupt control and not worry about efficiency. -:*/ - -/*G:034 - * The Interrupt Descriptor Table (IDT). - * - * The IDT tells the processor what to do when an interrupt comes in. Each - * entry in the table is a 64-bit descriptor: this holds the privilege level, - * address of the handler, and... well, who cares? The Guest just asks the - * Host to make the change anyway, because the Host controls the real IDT. - */ -static void lguest_write_idt_entry(gate_desc *dt, - int entrynum, const gate_desc *g) -{ - /* - * The gate_desc structure is 8 bytes long: we hand it to the Host in - * two 32-bit chunks. The whole 32-bit kernel used to hand descriptors - * around like this; typesafety wasn't a big concern in Linux's early - * years. - */ - u32 *desc = (u32 *)g; - /* Keep the local copy up to date. */ - native_write_idt_entry(dt, entrynum, g); - /* Tell Host about this new entry. */ - hcall(LHCALL_LOAD_IDT_ENTRY, entrynum, desc[0], desc[1], 0); -} - -/* - * Changing to a different IDT is very rare: we keep the IDT up-to-date every - * time it is written, so we can simply loop through all entries and tell the - * Host about them. - */ -static void lguest_load_idt(const struct desc_ptr *desc) -{ - unsigned int i; - struct desc_struct *idt = (void *)desc->address; - - for (i = 0; i < (desc->size+1)/8; i++) - hcall(LHCALL_LOAD_IDT_ENTRY, i, idt[i].a, idt[i].b, 0); -} - -/* - * The Global Descriptor Table. - * - * The Intel architecture defines another table, called the Global Descriptor - * Table (GDT). You tell the CPU where it is (and its size) using the "lgdt" - * instruction, and then several other instructions refer to entries in the - * table. There are three entries which the Switcher needs, so the Host simply - * controls the entire thing and the Guest asks it to make changes using the - * LOAD_GDT hypercall. - * - * This is the exactly like the IDT code. - */ -static void lguest_load_gdt(const struct desc_ptr *desc) -{ - unsigned int i; - struct desc_struct *gdt = (void *)desc->address; - - for (i = 0; i < (desc->size+1)/8; i++) - hcall(LHCALL_LOAD_GDT_ENTRY, i, gdt[i].a, gdt[i].b, 0); -} - -/* - * For a single GDT entry which changes, we simply change our copy and - * then tell the host about it. - */ -static void lguest_write_gdt_entry(struct desc_struct *dt, int entrynum, - const void *desc, int type) -{ - native_write_gdt_entry(dt, entrynum, desc, type); - /* Tell Host about this new entry. */ - hcall(LHCALL_LOAD_GDT_ENTRY, entrynum, - dt[entrynum].a, dt[entrynum].b, 0); -} - -/* - * There are three "thread local storage" GDT entries which change - * on every context switch (these three entries are how glibc implements - * __thread variables). As an optimization, we have a hypercall - * specifically for this case. - * - * Wouldn't it be nicer to have a general LOAD_GDT_ENTRIES hypercall - * which took a range of entries? - */ -static void lguest_load_tls(struct thread_struct *t, unsigned int cpu) -{ - /* - * There's one problem which normal hardware doesn't have: the Host - * can't handle us removing entries we're currently using. So we clear - * the GS register here: if it's needed it'll be reloaded anyway. - */ - lazy_load_gs(0); - lazy_hcall2(LHCALL_LOAD_TLS, __pa(&t->tls_array), cpu); -} - -/*G:038 - * That's enough excitement for now, back to ploughing through each of the - * different pv_ops structures (we're about 1/3 of the way through). - * - * This is the Local Descriptor Table, another weird Intel thingy. Linux only - * uses this for some strange applications like Wine. We don't do anything - * here, so they'll get an informative and friendly Segmentation Fault. - */ -static void lguest_set_ldt(const void *addr, unsigned entries) -{ -} - -/* - * This loads a GDT entry into the "Task Register": that entry points to a - * structure called the Task State Segment. Some comments scattered though the - * kernel code indicate that this used for task switching in ages past, along - * with blood sacrifice and astrology. - * - * Now there's nothing interesting in here that we don't get told elsewhere. - * But the native version uses the "ltr" instruction, which makes the Host - * complain to the Guest about a Segmentation Fault and it'll oops. So we - * override the native version with a do-nothing version. - */ -static void lguest_load_tr_desc(void) -{ -} - -/* - * The "cpuid" instruction is a way of querying both the CPU identity - * (manufacturer, model, etc) and its features. It was introduced before the - * Pentium in 1993 and keeps getting extended by both Intel, AMD and others. - * As you might imagine, after a decade and a half this treatment, it is now a - * giant ball of hair. Its entry in the current Intel manual runs to 28 pages. - * - * This instruction even it has its own Wikipedia entry. The Wikipedia entry - * has been translated into 6 languages. I am not making this up! - * - * We could get funky here and identify ourselves as "GenuineLguest", but - * instead we just use the real "cpuid" instruction. Then I pretty much turned - * off feature bits until the Guest booted. (Don't say that: you'll damage - * lguest sales!) Shut up, inner voice! (Hey, just pointing out that this is - * hardly future proof.) No one's listening! They don't like you anyway, - * parenthetic weirdo! - * - * Replacing the cpuid so we can turn features off is great for the kernel, but - * anyone (including userspace) can just use the raw "cpuid" instruction and - * the Host won't even notice since it isn't privileged. So we try not to get - * too worked up about it. - */ -static void lguest_cpuid(unsigned int *ax, unsigned int *bx, - unsigned int *cx, unsigned int *dx) -{ - int function = *ax; - - native_cpuid(ax, bx, cx, dx); - switch (function) { - /* - * CPUID 0 gives the highest legal CPUID number (and the ID string). - * We futureproof our code a little by sticking to known CPUID values. - */ - case 0: - if (*ax > 5) - *ax = 5; - break; - - /* - * CPUID 1 is a basic feature request. - * - * CX: we only allow kernel to see SSE3, CMPXCHG16B and SSSE3 - * DX: SSE, SSE2, FXSR, MMX, CMOV, CMPXCHG8B, TSC, FPU and PAE. - */ - case 1: - *cx &= 0x00002201; - *dx &= 0x07808151; - /* - * The Host can do a nice optimization if it knows that the - * kernel mappings (addresses above 0xC0000000 or whatever - * PAGE_OFFSET is set to) haven't changed. But Linux calls - * flush_tlb_user() for both user and kernel mappings unless - * the Page Global Enable (PGE) feature bit is set. - */ - *dx |= 0x00002000; - /* - * We also lie, and say we're family id 5. 6 or greater - * leads to a rdmsr in early_init_intel which we can't handle. - * Family ID is returned as bits 8-12 in ax. - */ - *ax &= 0xFFFFF0FF; - *ax |= 0x00000500; - break; - - /* - * This is used to detect if we're running under KVM. We might be, - * but that's a Host matter, not us. So say we're not. - */ - case KVM_CPUID_SIGNATURE: - *bx = *cx = *dx = 0; - break; - - /* - * 0x80000000 returns the highest Extended Function, so we futureproof - * like we do above by limiting it to known fields. - */ - case 0x80000000: - if (*ax > 0x80000008) - *ax = 0x80000008; - break; - - /* - * PAE systems can mark pages as non-executable. Linux calls this the - * NX bit. Intel calls it XD (eXecute Disable), AMD EVP (Enhanced - * Virus Protection). We just switch it off here, since we don't - * support it. - */ - case 0x80000001: - *dx &= ~(1 << 20); - break; - } -} - -/* - * Intel has four control registers, imaginatively named cr0, cr2, cr3 and cr4. - * I assume there's a cr1, but it hasn't bothered us yet, so we'll not bother - * it. The Host needs to know when the Guest wants to change them, so we have - * a whole series of functions like read_cr0() and write_cr0(). - * - * We start with cr0. cr0 allows you to turn on and off all kinds of basic - * features, but the only cr0 bit that Linux ever used at runtime was the - * horrifically-named Task Switched (TS) bit at bit 3 (ie. 8) - * - * What does the TS bit do? Well, it causes the CPU to trap (interrupt 7) if - * the floating point unit is used. Which allows us to restore FPU state - * lazily after a task switch if we wanted to, but wouldn't a name like - * "FPUTRAP bit" be a little less cryptic? - * - * Fortunately, Linux keeps it simple and doesn't use TS, so we can ignore - * cr0. - */ -static void lguest_write_cr0(unsigned long val) -{ -} - -static unsigned long lguest_read_cr0(void) -{ - return 0; -} - -/* - * cr2 is the virtual address of the last page fault, which the Guest only ever - * reads. The Host kindly writes this into our "struct lguest_data", so we - * just read it out of there. - */ -static unsigned long lguest_read_cr2(void) -{ - return lguest_data.cr2; -} - -/* See lguest_set_pte() below. */ -static bool cr3_changed = false; -static unsigned long current_cr3; - -/* - * cr3 is the current toplevel pagetable page: the principle is the same as - * cr0. Keep a local copy, and tell the Host when it changes. - */ -static void lguest_write_cr3(unsigned long cr3) -{ - lazy_hcall1(LHCALL_NEW_PGTABLE, cr3); - current_cr3 = cr3; - - /* These two page tables are simple, linear, and used during boot */ - if (cr3 != __pa_symbol(swapper_pg_dir) && - cr3 != __pa_symbol(initial_page_table)) - cr3_changed = true; -} - -static unsigned long lguest_read_cr3(void) -{ - return current_cr3; -} - -/* cr4 is used to enable and disable PGE, but we don't care. */ -static unsigned long lguest_read_cr4(void) -{ - return 0; -} - -static void lguest_write_cr4(unsigned long val) -{ -} - -/* - * Page Table Handling. - * - * Now would be a good time to take a rest and grab a coffee or similarly - * relaxing stimulant. The easy parts are behind us, and the trek gradually - * winds uphill from here. - * - * Quick refresher: memory is divided into "pages" of 4096 bytes each. The CPU - * maps virtual addresses to physical addresses using "page tables". We could - * use one huge index of 1 million entries: each addre |