diff options
Diffstat (limited to 'arch/x86/lguest')
| -rw-r--r-- | arch/x86/lguest/boot.c | 47 | ||||
| -rw-r--r-- | arch/x86/lguest/i386_head.S | 105 |
2 files changed, 130 insertions, 22 deletions
diff --git a/arch/x86/lguest/boot.c b/arch/x86/lguest/boot.c index 9257510b4836..4996cf5f73a0 100644 --- a/arch/x86/lguest/boot.c +++ b/arch/x86/lguest/boot.c @@ -324,9 +324,8 @@ static void lguest_load_gdt(const struct desc_ptr *desc) } /* - * For a single GDT entry which changes, we do the lazy thing: alter our GDT, - * then tell the Host to reload the entire thing. This operation is so rare - * that this naive implementation is reasonable. + * 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) @@ -338,9 +337,13 @@ static void lguest_write_gdt_entry(struct desc_struct *dt, int entrynum, } /* - * OK, I lied. There are three "thread local storage" GDT entries which change + * There are three "thread local storage" GDT entries which change * on every context switch (these three entries are how glibc implements - * __thread variables). So we have a hypercall specifically for this case. + * __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) { @@ -528,7 +531,10 @@ static void lguest_write_cr3(unsigned long cr3) { lguest_data.pgdir = cr3; lazy_hcall1(LHCALL_NEW_PGTABLE, cr3); - cr3_changed = true; + + /* These two page tables are simple, linear, and used during boot */ + if (cr3 != __pa(swapper_pg_dir) && cr3 != __pa(initial_page_table)) + cr3_changed = true; } static unsigned long lguest_read_cr3(void) @@ -700,9 +706,9 @@ static void lguest_set_pmd(pmd_t *pmdp, pmd_t pmdval) * to forget all of them. Fortunately, this is very rare. * * ... except in early boot when the kernel sets up the initial pagetables, - * which makes booting astonishingly slow: 1.83 seconds! So we don't even tell - * the Host anything changed until we've done the first page table switch, - * which brings boot back to 0.25 seconds. + * which makes booting astonishingly slow: 48 seconds! So we don't even tell + * the Host anything changed until we've done the first real page table switch, + * which brings boot back to 4.3 seconds. */ static void lguest_set_pte(pte_t *ptep, pte_t pteval) { @@ -788,22 +794,22 @@ static void lguest_flush_tlb_kernel(void) * simple as setting a bit. We don't actually "ack" interrupts as such, we * just mask and unmask them. I wonder if we should be cleverer? */ -static void disable_lguest_irq(unsigned int irq) +static void disable_lguest_irq(struct irq_data *data) { - set_bit(irq, lguest_data.blocked_interrupts); + set_bit(data->irq, lguest_data.blocked_interrupts); } -static void enable_lguest_irq(unsigned int irq) +static void enable_lguest_irq(struct irq_data *data) { - clear_bit(irq, lguest_data.blocked_interrupts); + clear_bit(data->irq, lguest_data.blocked_interrupts); } /* This structure describes the lguest IRQ controller. */ static struct irq_chip lguest_irq_controller = { .name = "lguest", - .mask = disable_lguest_irq, - .mask_ack = disable_lguest_irq, - .unmask = enable_lguest_irq, + .irq_mask = disable_lguest_irq, + .irq_mask_ack = disable_lguest_irq, + .irq_unmask = enable_lguest_irq, }; /* @@ -835,12 +841,12 @@ static void __init lguest_init_IRQ(void) * rather than set them in lguest_init_IRQ we are called here every time an * lguest device needs an interrupt. * - * FIXME: irq_to_desc_alloc_node() can fail due to lack of memory, we should + * FIXME: irq_alloc_desc_at() can fail due to lack of memory, we should * pass that up! */ void lguest_setup_irq(unsigned int irq) { - irq_to_desc_alloc_node(irq, 0); + irq_alloc_desc_at(irq, 0); set_irq_chip_and_handler_name(irq, &lguest_irq_controller, handle_level_irq, "level"); } @@ -999,7 +1005,7 @@ static void lguest_time_init(void) clockevents_register_device(&lguest_clockevent); /* Finally, we unblock the timer interrupt. */ - enable_lguest_irq(0); + clear_bit(0, lguest_data.blocked_interrupts); } /* @@ -1346,9 +1352,6 @@ __init void lguest_init(void) */ switch_to_new_gdt(0); - /* We actually boot with all memory mapped, but let's say 128MB. */ - max_pfn_mapped = (128*1024*1024) >> PAGE_SHIFT; - /* * The Host<->Guest Switcher lives at the top of our address space, and * the Host told us how big it is when we made LGUEST_INIT hypercall: diff --git a/arch/x86/lguest/i386_head.S b/arch/x86/lguest/i386_head.S index 4f420c2f2d55..e7d5382ef263 100644 --- a/arch/x86/lguest/i386_head.S +++ b/arch/x86/lguest/i386_head.S @@ -4,6 +4,7 @@ #include <asm/asm-offsets.h> #include <asm/thread_info.h> #include <asm/processor-flags.h> +#include <asm/pgtable.h> /*G:020 * Our story starts with the kernel booting into startup_32 in @@ -37,9 +38,113 @@ ENTRY(lguest_entry) /* Set up the initial stack so we can run C code. */ movl $(init_thread_union+THREAD_SIZE),%esp + call init_pagetables + /* Jumps are relative: we're running __PAGE_OFFSET too low. */ jmp lguest_init+__PAGE_OFFSET +/* + * Initialize page tables. This creates a PDE and a set of page + * tables, which are located immediately beyond __brk_base. The variable + * _brk_end is set up to point to the first "safe" location. + * Mappings are created both at virtual address 0 (identity mapping) + * and PAGE_OFFSET for up to _end. + * + * FIXME: This code is taken verbatim from arch/x86/kernel/head_32.S: they + * don't have a stack at this point, so we can't just use call and ret. + */ +init_pagetables: +#if PTRS_PER_PMD > 1 +#define PAGE_TABLE_SIZE(pages) (((pages) / PTRS_PER_PMD) + PTRS_PER_PGD) +#else +#define PAGE_TABLE_SIZE(pages) ((pages) / PTRS_PER_PGD) +#endif +#define pa(X) ((X) - __PAGE_OFFSET) + +/* Enough space to fit pagetables for the low memory linear map */ +MAPPING_BEYOND_END = \ + PAGE_TABLE_SIZE(((1<<32) - __PAGE_OFFSET) >> PAGE_SHIFT) << PAGE_SHIFT +#ifdef CONFIG_X86_PAE + + /* + * In PAE mode initial_page_table is statically defined to contain + * enough entries to cover the VMSPLIT option (that is the top 1, 2 or 3 + * entries). The identity mapping is handled by pointing two PGD entries + * to the first kernel PMD. + * + * Note the upper half of each PMD or PTE are always zero at this stage. + */ + +#define KPMDS (((-__PAGE_OFFSET) >> 30) & 3) /* Number of kernel PMDs */ + + xorl %ebx,%ebx /* %ebx is kept at zero */ + + movl $pa(__brk_base), %edi + movl $pa(initial_pg_pmd), %edx + movl $PTE_IDENT_ATTR, %eax +10: + leal PDE_IDENT_ATTR(%edi),%ecx /* Create PMD entry */ + movl %ecx,(%edx) /* Store PMD entry */ + /* Upper half already zero */ + addl $8,%edx + movl $512,%ecx +11: + stosl + xchgl %eax,%ebx + stosl + xchgl %eax,%ebx + addl $0x1000,%eax + loop 11b + + /* + * End condition: we must map up to the end + MAPPING_BEYOND_END. + */ + movl $pa(_end) + MAPPING_BEYOND_END + PTE_IDENT_ATTR, %ebp + cmpl %ebp,%eax + jb 10b +1: + addl $__PAGE_OFFSET, %edi + movl %edi, pa(_brk_end) + shrl $12, %eax + movl %eax, pa(max_pfn_mapped) + + /* Do early initialization of the fixmap area */ + movl $pa(initial_pg_fixmap)+PDE_IDENT_ATTR,%eax + movl %eax,pa(initial_pg_pmd+0x1000*KPMDS-8) +#else /* Not PAE */ + +page_pde_offset = (__PAGE_OFFSET >> 20); + + movl $pa(__brk_base), %edi + movl $pa(initial_page_table), %edx + movl $PTE_IDENT_ATTR, %eax +10: + leal PDE_IDENT_ATTR(%edi),%ecx /* Create PDE entry */ + movl %ecx,(%edx) /* Store identity PDE entry */ + movl %ecx,page_pde_offset(%edx) /* Store kernel PDE entry */ + addl $4,%edx + movl $1024, %ecx +11: + stosl + addl $0x1000,%eax + loop 11b + /* + * End condition: we must map up to the end + MAPPING_BEYOND_END. + */ + movl $pa(_end) + MAPPING_BEYOND_END + PTE_IDENT_ATTR, %ebp + cmpl %ebp,%eax + jb 10b + addl $__PAGE_OFFSET, %edi + movl %edi, pa(_brk_end) + shrl $12, %eax + movl %eax, pa(max_pfn_mapped) + + /* Do early initialization of the fixmap area */ + movl $pa(initial_pg_fixmap)+PDE_IDENT_ATTR,%eax + movl %eax,pa(initial_page_table+0xffc) +#endif + ret + /*G:055 * We create a macro which puts the assembler code between lgstart_ and lgend_ * markers. These templates are put in the .text section: they can't be |
