diff options
| -rw-r--r-- | Documentation/virtual/lguest/lguest.c | 12 | ||||
| -rw-r--r-- | arch/x86/include/asm/lguest_hcall.h | 1 | ||||
| -rw-r--r-- | arch/x86/lguest/boot.c | 21 | ||||
| -rw-r--r-- | arch/x86/lguest/i386_head.S | 18 | ||||
| -rw-r--r-- | drivers/lguest/core.c | 2 | ||||
| -rw-r--r-- | drivers/lguest/interrupts_and_traps.c | 4 | ||||
| -rw-r--r-- | drivers/lguest/lguest_user.c | 17 | ||||
| -rw-r--r-- | drivers/lguest/page_tables.c | 4 | ||||
| -rw-r--r-- | drivers/lguest/x86/core.c | 10 |
9 files changed, 50 insertions, 39 deletions
diff --git a/Documentation/virtual/lguest/lguest.c b/Documentation/virtual/lguest/lguest.c index 80261d3..043bd7d 100644 --- a/Documentation/virtual/lguest/lguest.c +++ b/Documentation/virtual/lguest/lguest.c @@ -51,7 +51,7 @@ #include <asm/bootparam.h> #include "../../../include/linux/lguest_launcher.h" /*L:110 - * We can ignore the 42 include files we need for this program, but I do want + * We can ignore the 43 include files we need for this program, but I do want * to draw attention to the use of kernel-style types. * * As Linus said, "C is a Spartan language, and so should your naming be." I @@ -65,7 +65,6 @@ typedef uint16_t u16; typedef uint8_t u8; /*:*/ -#define PAGE_PRESENT 0x7 /* Present, RW, Execute */ #define BRIDGE_PFX "bridge:" #ifndef SIOCBRADDIF #define SIOCBRADDIF 0x89a2 /* add interface to bridge */ @@ -1359,7 +1358,7 @@ static void setup_console(void) * --sharenet=<name> option which opens or creates a named pipe. This can be * used to send packets to another guest in a 1:1 manner. * - * More sopisticated is to use one of the tools developed for project like UML + * More sophisticated is to use one of the tools developed for project like UML * to do networking. * * Faster is to do virtio bonding in kernel. Doing this 1:1 would be @@ -1369,7 +1368,7 @@ static void setup_console(void) * multiple inter-guest channels behind one interface, although it would * require some manner of hotplugging new virtio channels. * - * Finally, we could implement a virtio network switch in the kernel. + * Finally, we could use a virtio network switch in the kernel, ie. vhost. :*/ static u32 str2ip(const char *ipaddr) @@ -2006,10 +2005,7 @@ int main(int argc, char *argv[]) /* Tell the entry path not to try to reload segment registers. */ boot->hdr.loadflags |= KEEP_SEGMENTS; - /* - * We tell the kernel to initialize the Guest: this returns the open - * /dev/lguest file descriptor. - */ + /* We tell the kernel to initialize the Guest. */ tell_kernel(start); /* Ensure that we terminate if a device-servicing child dies. */ diff --git a/arch/x86/include/asm/lguest_hcall.h b/arch/x86/include/asm/lguest_hcall.h index b60f292..879fd7d 100644 --- a/arch/x86/include/asm/lguest_hcall.h +++ b/arch/x86/include/asm/lguest_hcall.h @@ -61,6 +61,7 @@ hcall(unsigned long call, : "memory"); return call; } +/*:*/ /* Can't use our min() macro here: needs to be a constant */ #define LGUEST_IRQS (NR_IRQS < 32 ? NR_IRQS: 32) diff --git a/arch/x86/lguest/boot.c b/arch/x86/lguest/boot.c index 719a32c..7427990 100644 --- a/arch/x86/lguest/boot.c +++ b/arch/x86/lguest/boot.c @@ -71,7 +71,8 @@ #include <asm/stackprotector.h> #include <asm/reboot.h> /* for struct machine_ops */ -/*G:010 Welcome to the Guest! +/*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 @@ -190,15 +191,23 @@ static void lazy_hcall4(unsigned long call, #endif /*G:036 - * When lazy mode is turned off reset the per-cpu lazy mode variable and then - * issue the do-nothing hypercall to flush any stored calls. -:*/ + * 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); @@ -640,7 +649,7 @@ static void lguest_write_cr4(unsigned long val) /* * The Guest calls this after it has set a second-level entry (pte), ie. to map - * a page into a process' address space. Wetell the Host the toplevel and + * a page into a process' address space. We tell the Host the toplevel and * address this corresponds to. The Guest uses one pagetable per process, so * we need to tell the Host which one we're changing (mm->pgd). */ @@ -1139,7 +1148,7 @@ static struct notifier_block paniced = { static __init char *lguest_memory_setup(void) { /* - *The Linux bootloader header contains an "e820" memory map: the + * The Linux bootloader header contains an "e820" memory map: the * Launcher populated the first entry with our memory limit. */ e820_add_region(boot_params.e820_map[0].addr, diff --git a/arch/x86/lguest/i386_head.S b/arch/x86/lguest/i386_head.S index c8c95e5..cfa23e3 100644 --- a/arch/x86/lguest/i386_head.S +++ b/arch/x86/lguest/i386_head.S @@ -6,18 +6,22 @@ #include <asm/processor-flags.h> /*G:020 - * Our story starts with the kernel booting into startup_32 in - * arch/x86/kernel/head_32.S. It expects a boot header, which is created by - * the bootloader (the Launcher in our case). + + * Our story starts with the bzImage: booting starts at startup_32 in + * arch/x86/boot/compressed/head_32.S. This merely uncompresses the real + * kernel in place and then jumps into it: startup_32 in + * arch/x86/kernel/head_32.S. Both routines expects a boot header in the %esi + * register, which is created by the bootloader (the Launcher in our case). * * The startup_32 function does very little: it clears the uninitialized global * C variables which we expect to be zero (ie. BSS) and then copies the boot - * header and kernel command line somewhere safe. Finally it checks the - * 'hardware_subarch' field. This was introduced in 2.6.24 for lguest and Xen: - * if it's set to '1' (lguest's assigned number), then it calls us here. + * header and kernel command line somewhere safe, and populates some initial + * page tables. Finally it checks the 'hardware_subarch' field. This was + * introduced in 2.6.24 for lguest and Xen: if it's set to '1' (lguest's + * assigned number), then it calls us here. * * WARNING: be very careful here! We're running at addresses equal to physical - * addesses (around 0), not above PAGE_OFFSET as most code expectes + * addesses (around 0), not above PAGE_OFFSET as most code expects * (eg. 0xC0000000). Jumps are relative, so they're OK, but we can't touch any * data without remembering to subtract __PAGE_OFFSET! * diff --git a/drivers/lguest/core.c b/drivers/lguest/core.c index efa2024..2535933 100644 --- a/drivers/lguest/core.c +++ b/drivers/lguest/core.c @@ -117,7 +117,7 @@ static __init int map_switcher(void) /* * Now the Switcher is mapped at the right address, we can't fail! - * Copy in the compiled-in Switcher code (from <arch>_switcher.S). + * Copy in the compiled-in Switcher code (from x86/switcher_32.S). */ memcpy(switcher_vma->addr, start_switcher_text, end_switcher_text - start_switcher_text); diff --git a/drivers/lguest/interrupts_and_traps.c b/drivers/lguest/interrupts_and_traps.c index f0c1715..28433a1 100644 --- a/drivers/lguest/interrupts_and_traps.c +++ b/drivers/lguest/interrupts_and_traps.c @@ -427,8 +427,8 @@ void pin_stack_pages(struct lg_cpu *cpu) /* * Direct traps also mean that we need to know whenever the Guest wants to use - * a different kernel stack, so we can change the IDT entries to use that - * stack. The IDT entries expect a virtual address, so unlike most addresses + * a different kernel stack, so we can change the guest TSS to use that + * stack. The TSS entries expect a virtual address, so unlike most addresses * the Guest gives us, the "esp" (stack pointer) value here is virtual, not * physical. * diff --git a/drivers/lguest/lguest_user.c b/drivers/lguest/lguest_user.c index 948c547..f97e625 100644 --- a/drivers/lguest/lguest_user.c +++ b/drivers/lguest/lguest_user.c @@ -1,8 +1,10 @@ -/*P:200 This contains all the /dev/lguest code, whereby the userspace launcher - * controls and communicates with the Guest. For example, the first write will - * tell us the Guest's memory layout and entry point. A read will run the - * Guest until something happens, such as a signal or the Guest doing a NOTIFY - * out to the Launcher. +/*P:200 This contains all the /dev/lguest code, whereby the userspace + * launcher controls and communicates with the Guest. For example, + * the first write will tell us the Guest's memory layout and entry + * point. A read will run the Guest until something happens, such as + * a signal or the Guest doing a NOTIFY out to the Launcher. There is + * also a way for the Launcher to attach eventfds to particular NOTIFY + * values instead of returning from the read() call. :*/ #include <linux/uaccess.h> #include <linux/miscdevice.h> @@ -357,8 +359,8 @@ static int initialize(struct file *file, const unsigned long __user *input) goto free_eventfds; /* - * Initialize the Guest's shadow page tables, using the toplevel - * address the Launcher gave us. This allocates memory, so can fail. + * Initialize the Guest's shadow page tables. This allocates + * memory, so can fail. */ err = init_guest_pagetable(lg); if (err) @@ -516,6 +518,7 @@ static const struct file_operations lguest_fops = { .read = read, .llseek = default_llseek, }; +/*:*/ /* * This is a textbook example of a "misc" character device. Populate a "struct diff --git a/drivers/lguest/page_tables.c b/drivers/lguest/page_tables.c index 0002622..3b62be16 100644 --- a/drivers/lguest/page_tables.c +++ b/drivers/lguest/page_tables.c @@ -155,7 +155,7 @@ static pte_t *spte_addr(struct lg_cpu *cpu, pgd_t spgd, unsigned long vaddr) } /* - * These functions are just like the above two, except they access the Guest + * These functions are just like the above, except they access the Guest * page tables. Hence they return a Guest address. */ static unsigned long gpgd_addr(struct lg_cpu *cpu, unsigned long vaddr) @@ -195,7 +195,7 @@ static unsigned long gpte_addr(struct lg_cpu *cpu, #endif /*:*/ -/*M:014 +/*M:007 * get_pfn is slow: we could probably try to grab batches of pages here as * an optimization (ie. pre-faulting). :*/ diff --git a/drivers/lguest/x86/core.c b/drivers/lguest/x86/core.c index ec0cdfc..3b9b810 100644 --- a/drivers/lguest/x86/core.c +++ b/drivers/lguest/x86/core.c @@ -272,7 +272,7 @@ static int emulate_insn(struct lg_cpu *cpu) unsigned int insnlen = 0, in = 0, shift = 0; /* * The eip contains the *virtual* address of the Guest's instruction: - * guest_pa just subtracts the Guest's page_offset. + * walk the Guest's page tables to find the "physical" address. */ unsigned long physaddr = guest_pa(cpu, cpu->regs->eip); @@ -409,7 +409,7 @@ void lguest_arch_handle_trap(struct lg_cpu *cpu) * These values mean a real interrupt occurred, in which case * the Host handler has already been run. We just do a * friendly check if another process should now be run, then - * return to run the Guest again + * return to run the Guest again. */ cond_resched(); return; @@ -459,7 +459,7 @@ void __init lguest_arch_host_init(void) int i; /* - * Most of the i386/switcher.S doesn't care that it's been moved; on + * Most of the x86/switcher_32.S doesn't care that it's been moved; on * Intel, jumps are relative, and it doesn't access any references to * external code or data. * @@ -587,7 +587,7 @@ void __init lguest_arch_host_init(void) clear_cpu_cap(&boot_cpu_data, X86_FEATURE_PGE); } put_online_cpus(); -}; +} /*:*/ void __exit lguest_arch_host_fini(void) @@ -670,8 +670,6 @@ int lguest_arch_init_hypercalls(struct lg_cpu *cpu) /*:*/ /*L:030 - * lguest_arch_setup_regs() - * * Most of the Guest's registers are left alone: we used get_zeroed_page() to * allocate the structure, so they will be 0. */ |