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

["Jan Beulich" <JBeulich@xxxxxxxx>]

... and use it as basis for a proper ioremap() on x86.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>

--- 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__ */

Attachment: vmap.patch
Description: Text document

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