Re: [Xen-devel] [PATCH] implement vmap()

[Keir Fraser <keir@xxxxxxx>]

On 09/11/2012 13:28, "Jan Beulich" <JBeulich@xxxxxxxx> wrote:

> ... and use it as basis for a proper ioremap() on x86.
> 
> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>

Acked-by: Keir Fraser <keir@xxxxxxx>

> --- a/xen/arch/x86/mm.c
> +++ b/xen/arch/x86/mm.c
> @@ -100,6 +100,7 @@
>  #include <xen/iocap.h>
>  #include <xen/guest_access.h>
>  #include <xen/pfn.h>
> +#include <xen/vmap.h>
>  #include <xen/xmalloc.h>
>  #include <xen/efi.h>
>  #include <xen/grant_table.h>
> @@ -5460,6 +5561,32 @@ void __set_fixmap(
>      map_pages_to_xen(fix_to_virt(idx), mfn, 1, flags);
>  }
>  
> +void *__init arch_vmap_virt_end(void)
> +{
> +    return (void *)fix_to_virt(__end_of_fixed_addresses);
> +}
> +
> +void __iomem *ioremap(paddr_t pa, size_t len)
> +{
> +    unsigned long pfn = PFN_DOWN(pa);
> +    void *va;
> +
> +    WARN_ON(page_is_ram_type(pfn, RAM_TYPE_CONVENTIONAL));
> +
> +    /* The low first Mb is always mapped. */
> +    if ( !((pa + len - 1) >> 20) )
> +        va = __va(pa);
> +    else
> +    {
> +        unsigned int offs = pa & (PAGE_SIZE - 1);
> +        unsigned int nr = PFN_UP(offs + len);
> +
> +        va = __vmap(&pfn, nr, 1, 1, PAGE_HYPERVISOR_NOCACHE) + offs;
> +    }
> +
> +    return (void __force __iomem *)va;
> +}
> +
>  #ifdef MEMORY_GUARD
>  
>  void memguard_init(void)
> --- a/xen/arch/x86/setup.c
> +++ b/xen/arch/x86/setup.c
> @@ -1104,6 +1104,7 @@ void __init __start_xen(unsigned long mb
>      end_boot_allocator();
>      system_state = SYS_STATE_boot;
>  
> +    vm_init();
>      vesa_init();
>  
>      softirq_init();
> --- a/xen/common/Makefile
> +++ b/xen/common/Makefile
> @@ -36,6 +36,7 @@ obj-y += time.o
>  obj-y += timer.o
>  obj-y += trace.o
>  obj-y += version.o
> +obj-y += vmap.o
>  obj-y += vsprintf.o
>  obj-y += wait.o
>  obj-y += xmalloc_tlsf.o
> --- /dev/null
> +++ b/xen/common/vmap.c
> @@ -0,0 +1,204 @@
> +#ifdef VMAP_VIRT_START
> +#include <xen/bitmap.h>
> +#include <xen/cache.h>
> +#include <xen/init.h>
> +#include <xen/mm.h>
> +#include <xen/pfn.h>
> +#include <xen/spinlock.h>
> +#include <xen/types.h>
> +#include <xen/vmap.h>
> +#include <asm/page.h>
> +
> +static DEFINE_SPINLOCK(vm_lock);
> +static void *__read_mostly vm_base;
> +#define vm_bitmap ((unsigned long *)vm_base)
> +/* highest allocated bit in the bitmap */
> +static unsigned int __read_mostly vm_top;
> +/* total number of bits in the bitmap */
> +static unsigned int __read_mostly vm_end;
> +/* lowest known clear bit in the bitmap */
> +static unsigned int vm_low;
> +
> +void __init vm_init(void)
> +{
> +    unsigned int i, nr;
> +    unsigned long va;
> +
> +    vm_base = (void *)VMAP_VIRT_START;
> +    vm_end = PFN_DOWN(arch_vmap_virt_end() - vm_base);
> +    vm_low = PFN_UP((vm_end + 7) / 8);
> +    nr = PFN_UP((vm_low + 7) / 8);
> +    vm_top = nr * PAGE_SIZE * 8;
> +
> +    for ( i = 0, va = (unsigned long)vm_bitmap; i < nr; ++i, va += PAGE_SIZE
> )
> +    {
> +        struct page_info *pg = alloc_domheap_page(NULL, 0);
> +
> +        map_pages_to_xen(va, page_to_mfn(pg), 1, PAGE_HYPERVISOR);
> +        clear_page((void *)va);
> +    }
> +    bitmap_fill(vm_bitmap, vm_low);
> +
> +    /* Populate page tables for the bitmap if necessary. */
> +    map_pages_to_xen(va, 0, vm_low - nr, MAP_SMALL_PAGES);
> +}
> +
> +void *vm_alloc(unsigned int nr, unsigned int align)
> +{
> +    unsigned int start, bit;
> +
> +    if ( !align )
> +        align = 1;
> +    else if ( align & (align - 1) )
> +        align &= -align;
> +
> +    spin_lock(&vm_lock);
> +    for ( ; ; )
> +    {
> +        struct page_info *pg;
> +
> +        ASSERT(!test_bit(vm_low, vm_bitmap));
> +        for ( start = vm_low; ; )
> +        {
> +            bit = find_next_bit(vm_bitmap, vm_top, start + 1);
> +            if ( bit > vm_top )
> +                bit = vm_top;
> +            /*
> +             * Note that this skips the first bit, making the
> +             * corresponding page a guard one.
> +             */
> +            start = (start + align) & ~(align - 1);
> +            if ( start + nr <= bit )
> +                break;
> +            start = bit < vm_top ?
> +                    find_next_zero_bit(vm_bitmap, vm_top, bit + 1) : bit;
> +            if ( start >= vm_top )
> +                break;
> +        }
> +
> +        if ( start < vm_top )
> +            break;
> +
> +        spin_unlock(&vm_lock);
> +
> +        if ( vm_top >= vm_end )
> +            return NULL;
> +
> +        pg = alloc_domheap_page(NULL, 0);
> +        if ( !pg )
> +            return NULL;
> +
> +        spin_lock(&vm_lock);
> +
> +        if ( start >= vm_top )
> +        {
> +            unsigned long va = (unsigned long)vm_bitmap + vm_top / 8;
> +
> +            if ( !map_pages_to_xen(va, page_to_mfn(pg), 1, PAGE_HYPERVISOR) )
> +            {
> +                clear_page((void *)va);
> +                vm_top += PAGE_SIZE * 8;
> +                if ( vm_top > vm_end )
> +                    vm_top = vm_end;
> +                continue;
> +            }
> +        }
> +
> +        free_domheap_page(pg);
> +
> +        if ( start >= vm_top )
> +        {
> +            spin_unlock(&vm_lock);
> +            return NULL;
> +        }
> +    }
> +
> +    for ( bit = start; bit < start + nr; ++bit )
> +        __set_bit(bit, vm_bitmap);
> +    if ( start <= vm_low + 2 )
> +        vm_low = bit;
> +    spin_unlock(&vm_lock);
> +
> +    return vm_base + start * PAGE_SIZE;
> +}
> +
> +static unsigned int vm_index(const void *va)
> +{
> +    unsigned long addr = (unsigned long)va & ~(PAGE_SIZE - 1);
> +    unsigned int idx;
> +
> +    if ( addr < VMAP_VIRT_START + (vm_end / 8) ||
> +         addr >= VMAP_VIRT_START + vm_top * PAGE_SIZE )
> +        return 0;
> +
> +    idx = PFN_DOWN(va - vm_base);
> +    return !test_bit(idx - 1, vm_bitmap) &&
> +           test_bit(idx, vm_bitmap) ? idx : 0;
> +}
> +
> +static unsigned int vm_size(const void *va)
> +{
> +    unsigned int start = vm_index(va), end;
> +
> +    if ( !start )
> +        return 0;
> +
> +    end = find_next_zero_bit(vm_bitmap, vm_top, start + 1);
> +
> +    return min(end, vm_top) - start;
> +}
> +
> +void vm_free(const void *va)
> +{
> +    unsigned int bit = vm_index(va);
> +
> +    if ( !bit )
> +    {
> +        WARN_ON(va != NULL);
> +        return;
> +    }
> +
> +    spin_lock(&vm_lock);
> +    if ( bit < vm_low )
> +    {
> +        vm_low = bit - 1;
> +        while ( !test_bit(vm_low - 1, vm_bitmap) )
> +            --vm_low;
> +    }
> +    while ( __test_and_clear_bit(bit, vm_bitmap) )
> +        if ( ++bit == vm_top )
> +            break;
> +    spin_unlock(&vm_lock);
> +}
> +
> +void *__vmap(const unsigned long *mfn, unsigned int granularity,
> +             unsigned int nr, unsigned int align, unsigned int flags)
> +{
> +    void *va = vm_alloc(nr * granularity, align);
> +    unsigned long cur = (unsigned long)va;
> +
> +    for ( ; va && nr--; ++mfn, cur += PAGE_SIZE * granularity )
> +    {
> +        if ( map_pages_to_xen(cur, *mfn, granularity, flags) )
> +        {
> +            vunmap(va);
> +            va = NULL;
> +        }
> +    }
> +
> +    return va;
> +}
> +
> +void *vmap(const unsigned long *mfn, unsigned int nr)
> +{
> +    return __vmap(mfn, 1, nr, 1, PAGE_HYPERVISOR);
> +}
> +
> +void vunmap(const void *va)
> +{
> +    unsigned long addr = (unsigned long)va;
> +
> +    destroy_xen_mappings(addr, addr + PAGE_SIZE * vm_size(va));
> +    vm_free(va);
> +}
> +#endif
> --- a/xen/drivers/acpi/apei/erst.c
> +++ b/xen/drivers/acpi/apei/erst.c
> @@ -247,9 +247,6 @@ static int erst_exec_move_data(struct ap
>  {
> int rc;
> u64 offset;
> -#ifdef CONFIG_X86
> - enum fixed_addresses idx;
> -#endif
> void *src, *dst;
>  
> /* ioremap does not work in interrupt context */
> @@ -263,39 +260,11 @@ static int erst_exec_move_data(struct ap
> if (rc)
> return rc;
>  
> -#ifdef CONFIG_X86
> - switch (ctx->var2) {
> - case 0:
> -  return 0;
> - case 1 ... PAGE_SIZE:
> -  break;
> - default:
> -  printk(KERN_WARNING
> -         "MOVE_DATA cannot be used for %#"PRIx64" bytes of data\n",
> -         ctx->var2);
> -  return -EOPNOTSUPP;
> - }
> -
> - src = __acpi_map_table(ctx->src_base + offset, ctx->var2);
> -#else
> src = ioremap(ctx->src_base + offset, ctx->var2);
> -#endif
> if (!src)
> return -ENOMEM;
>  
> -#ifdef CONFIG_X86
> - BUILD_BUG_ON(FIX_ACPI_PAGES < 4);
> - idx = virt_to_fix((unsigned long)src + 2 * PAGE_SIZE);
> - offset += ctx->dst_base;
> - dst = (void *)fix_to_virt(idx) + (offset & ~PAGE_MASK);
> - set_fixmap(idx, offset);
> - if (PFN_DOWN(offset) != PFN_DOWN(offset + ctx->var2 - 1)) {
> -  idx = virt_to_fix((unsigned long)dst + PAGE_SIZE);
> -  set_fixmap(idx, offset + PAGE_SIZE);
> - }
> -#else
> dst = ioremap(ctx->dst_base + offset, ctx->var2);
> -#endif
> if (dst) {
> memmove(dst, src, ctx->var2);
> iounmap(dst);
> --- a/xen/drivers/video/vesa.c
> +++ b/xen/drivers/video/vesa.c
> @@ -10,6 +10,7 @@
>  #include <xen/xmalloc.h>
>  #include <xen/kernel.h>
>  #include <xen/vga.h>
> +#include <asm/io.h>
>  #include <asm/page.h>
>  #include "font.h"
>  
> @@ -101,13 +102,11 @@ void __init vesa_init(void)
>      if ( !line_len )
>          goto fail;
>  
> -    if ( map_pages_to_xen(IOREMAP_VIRT_START,
> -                          vlfb_info.lfb_base >> PAGE_SHIFT,
> -                          vram_remap >> PAGE_SHIFT,
> -                          PAGE_HYPERVISOR_NOCACHE) )
> +    lfb = ioremap(vlfb_info.lfb_base, vram_remap);
> +    if ( !lfb )
>          goto fail;
>  
> -    lfb = memset((void *)IOREMAP_VIRT_START, 0, vram_remap);
> +    memset(lfb, 0, vram_remap);
>  
>      vga_puts = vesa_redraw_puts;
>  
> --- a/xen/include/asm-x86/config.h
> +++ b/xen/include/asm-x86/config.h
> @@ -144,7 +144,7 @@ extern unsigned char boot_edid_info[128]
>   *  0xffff828000000000 - 0xffff82bfffffffff [256GB, 2^38 bytes, PML4:261]
>   *    Machine-to-phys translation table.
>   *  0xffff82c000000000 - 0xffff82c3ffffffff [16GB,  2^34 bytes, PML4:261]
> - *    ioremap()/fixmap area.
> + *    vmap()/ioremap()/fixmap area.
>   *  0xffff82c400000000 - 0xffff82c43fffffff [1GB,   2^30 bytes, PML4:261]
>   *    Compatibility machine-to-phys translation table.
>   *  0xffff82c440000000 - 0xffff82c47fffffff [1GB,   2^30 bytes, PML4:261]
> @@ -205,11 +205,11 @@ extern unsigned char boot_edid_info[128]
>  /* Slot 261: machine-to-phys conversion table (256GB). */
>  #define RDWR_MPT_VIRT_START     (PML4_ADDR(261))
>  #define RDWR_MPT_VIRT_END       (RDWR_MPT_VIRT_START + MPT_VIRT_SIZE)
> -/* Slot 261: ioremap()/fixmap area (16GB). */
> -#define IOREMAP_VIRT_START      RDWR_MPT_VIRT_END
> -#define IOREMAP_VIRT_END        (IOREMAP_VIRT_START + GB(16))
> +/* Slot 261: vmap()/ioremap()/fixmap area (16GB). */
> +#define VMAP_VIRT_START         RDWR_MPT_VIRT_END
> +#define VMAP_VIRT_END           (VMAP_VIRT_START + GB(16))
>  /* Slot 261: compatibility machine-to-phys conversion table (1GB). */
> -#define RDWR_COMPAT_MPT_VIRT_START IOREMAP_VIRT_END
> +#define RDWR_COMPAT_MPT_VIRT_START VMAP_VIRT_END
>  #define RDWR_COMPAT_MPT_VIRT_END (RDWR_COMPAT_MPT_VIRT_START + GB(1))
>  /* Slot 261: high read-only compat machine-to-phys conversion table (1GB). */
>  #define HIRO_COMPAT_MPT_VIRT_START RDWR_COMPAT_MPT_VIRT_END
> --- a/xen/include/asm-x86/fixmap.h
> +++ b/xen/include/asm-x86/fixmap.h
> @@ -15,7 +15,7 @@
>  #include <xen/config.h>
>  #include <asm/page.h>
>  
> -#define FIXADDR_TOP (IOREMAP_VIRT_END - PAGE_SIZE)
> +#define FIXADDR_TOP (VMAP_VIRT_END - PAGE_SIZE)
>  
>  #ifndef __ASSEMBLY__
>  
> --- a/xen/include/asm-x86/io.h
> +++ b/xen/include/asm-x86/io.h
> @@ -1,14 +1,10 @@
>  #ifndef _ASM_IO_H
>  #define _ASM_IO_H
>  
> -#include <xen/config.h>
> +#include <xen/vmap.h>
>  #include <xen/types.h>
>  #include <asm/page.h>
>  
> -/* We don't need real ioremap() on Xen/x86. */
> -#define ioremap(x,l) (__va(x))
> -#define iounmap(p)   ((void)0)
> -
>  #define readb(x) (*(volatile char *)(x))
>  #define readw(x) (*(volatile short *)(x))
>  #define readl(x) (*(volatile int *)(x))
> --- /dev/null
> +++ b/xen/include/xen/vmap.h
> @@ -0,0 +1,24 @@
> +#if !defined(__XEN_VMAP_H__) && defined(VMAP_VIRT_START)
> +#define __XEN_VMAP_H__
> +
> +#include <xen/types.h>
> +
> +void *vm_alloc(unsigned int nr, unsigned int align);
> +void vm_free(const void *);
> +
> +void *__vmap(const unsigned long *mfn, unsigned int granularity,
> +             unsigned int nr, unsigned int align, unsigned int flags);
> +void *vmap(const unsigned long *mfn, unsigned int nr);
> +void vunmap(const void *);
> +
> +void __iomem *ioremap(paddr_t, size_t);
> +
> +static inline void iounmap(void __iomem *va)
> +{
> +    vunmap((void __force *)va);
> +}
> +
> +void vm_init(void);
> +void *arch_vmap_virt_end(void);
> +
> +#endif /* __XEN_VMAP_H__ */
> 
> 
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