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    Subject[PATCH] x86: mtrr cleanup for converting continuous to discrete layout v2
    Date
    From

    some BIOS like to use continus MTRR layout, and X driver can not add
    WB entries for graphical cards when 4g or more RAM installed.

    the patch will change MTRR to discrete.

    mtrr_chunk_size= could be used to have smaller continuous block to hold holes.
    default is 256m, could be set according to size of graphics card memory.

    v2: fix -1 for UC

    Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>

    Index: linux-2.6/arch/x86/kernel/cpu/mtrr/generic.c
    ===================================================================
    --- linux-2.6.orig/arch/x86/kernel/cpu/mtrr/generic.c
    +++ linux-2.6/arch/x86/kernel/cpu/mtrr/generic.c
    @@ -158,6 +158,20 @@ get_mtrr_var_range(unsigned int index, s
    rdmsr(MTRRphysMask_MSR(index), vr->mask_lo, vr->mask_hi);
    }

    +/* fill the MSR pair relating to a var range */
    +void fill_mtrr_var_range(unsigned int index,
    + u32 base_lo, u32 base_hi, u32 mask_lo, u32 mask_hi)
    +{
    + struct mtrr_var_range *vr;
    +
    + vr = mtrr_state.var_ranges;
    +
    + vr[index].base_lo = base_lo;
    + vr[index].base_hi = base_hi;
    + vr[index].mask_lo = mask_lo;
    + vr[index].mask_hi = mask_hi;
    +}
    +
    static void
    get_fixed_ranges(mtrr_type * frs)
    {
    Index: linux-2.6/arch/x86/kernel/cpu/mtrr/main.c
    ===================================================================
    --- linux-2.6.orig/arch/x86/kernel/cpu/mtrr/main.c
    +++ linux-2.6/arch/x86/kernel/cpu/mtrr/main.c
    @@ -37,6 +37,7 @@
    #include <linux/smp.h>
    #include <linux/cpu.h>
    #include <linux/mutex.h>
    +#include <linux/sort.h>

    #include <asm/e820.h>
    #include <asm/mtrr.h>
    @@ -609,6 +610,348 @@ static struct sysdev_driver mtrr_sysdev_
    .resume = mtrr_restore,
    };

    +static int disable_mtrr_cleanup;
    +
    +static int __init disable_mtrr_cleanup_setup(char *str)
    +{
    + disable_mtrr_cleanup = 1;
    + return 0;
    +}
    +early_param("disable_mtrr_cleanup", disable_mtrr_cleanup_setup);
    +
    +#define RANGE_NUM 256
    +
    +struct res_range {
    + size_t start;
    + size_t end;
    +};
    +
    +static void __init subtract_range(struct res_range *range, size_t start,
    + size_t end)
    +{
    + int i;
    + int j;
    +
    + for (j = 0; j < RANGE_NUM; j++) {
    + if (!range[j].end)
    + continue;
    +
    + if (start <= range[j].start && end >= range[j].end) {
    + range[j].start = 0;
    + range[j].end = 0;
    + continue;
    + }
    +
    + if (start <= range[j].start && end < range[j].end && range[j].start < end + 1) {
    + range[j].start = end + 1;
    + continue;
    + }
    +
    +
    + if (start > range[j].start && end >= range[j].end && range[j].end > start - 1) {
    + range[j].end = start - 1;
    + continue;
    + }
    +
    + if (start > range[j].start && end < range[j].end) {
    + /* find the new spare */
    + for (i = 0; i < RANGE_NUM; i++) {
    + if (range[i].end == 0)
    + break;
    + }
    + if (i < RANGE_NUM) {
    + range[i].end = range[j].end;
    + range[i].start = end + 1;
    + } else {
    + printk(KERN_ERR "run of slot in ranges\n");
    + }
    + range[j].end = start - 1;
    + continue;
    + }
    + }
    +}
    +
    +static int __cpuinit cmp_range(const void *x1, const void *x2)
    +{
    + const struct res_range *r1 = x1;
    + const struct res_range *r2 = x2;
    + s64 start1, start2;
    +
    + start1 = r1->start;
    + start2 = r2->start;
    +
    + return start1 - start2;
    +}
    +
    +struct var_mtrr_state {
    + unsigned long range_startk, range_sizek;
    + unsigned long chunk_sizek;
    + unsigned int reg;
    + unsigned address_bits;
    +};
    +
    +static void __init set_var_mtrr(
    + unsigned int reg, unsigned long basek, unsigned long sizek,
    + unsigned char type, unsigned address_bits)
    +{
    + u32 base_lo, base_hi, mask_lo, mask_hi;
    + unsigned address_mask_high;
    +
    + if (!sizek) {
    + fill_mtrr_var_range(reg, 0, 0, 0, 0);
    + return;
    + }
    +
    + address_mask_high = ((1u << (address_bits - 32u)) - 1u);
    +
    + base_hi = basek >> 22;
    + base_lo = basek << 10;
    +
    + if (sizek < 4*1024*1024) {
    + mask_hi = address_mask_high;
    + mask_lo = ~((sizek << 10) - 1);
    + } else {
    + mask_hi = address_mask_high & (~((sizek >> 22) - 1));
    + mask_lo = 0;
    + }
    +
    + base_lo |= type;
    + mask_lo |= 0x800;
    + fill_mtrr_var_range(reg, base_lo, base_hi, mask_lo, mask_hi);
    +}
    +
    +static unsigned int __init range_to_mtrr(unsigned int reg,
    + unsigned long range_startk, unsigned long range_sizek,
    + unsigned long next_range_startk, unsigned char type, unsigned address_bits)
    +{
    + if (!range_sizek || (reg >= num_var_ranges))
    + return reg;
    +
    + while (range_sizek) {
    + unsigned long max_align, align;
    + unsigned long sizek;
    + /* Compute the maximum size I can make a range */
    + if (range_startk)
    + max_align = ffs(range_startk) - 1;
    + else
    + max_align = 32;
    + align = fls(range_sizek) - 1;
    + if (align > max_align)
    + align = max_align;
    +
    + sizek = 1 << align;
    + printk(KERN_INFO "Setting variable MTRR %d, base: %ldMB, range: %ldMB, type %s\n",
    + reg, range_startk >> 10, sizek >> 10,
    + (type == MTRR_TYPE_UNCACHABLE)?"UC":
    + ((type == MTRR_TYPE_WRBACK)?"WB":"Other")
    + );
    + set_var_mtrr(reg++, range_startk, sizek, type, address_bits);
    + range_startk += sizek;
    + range_sizek -= sizek;
    + if (reg >= num_var_ranges)
    + break;
    + }
    + return reg;
    +}
    +
    +static void __init range_to_mtrr_with_hole(struct var_mtrr_state *state, unsigned long basek)
    +{
    + unsigned long hole_basek, hole_sizek;
    + unsigned long range0_basek, range0_sizek;
    + unsigned long range_basek, range_sizek;
    + unsigned long next_basek;
    + unsigned long chunk_sizek;
    +
    + hole_basek = 0;
    + hole_sizek = 0;
    + chunk_sizek = state->chunk_sizek;
    + range0_basek = state->range_startk;
    + next_basek = basek;
    +
    + /* try to append some small hole */
    + range0_sizek = ALIGN(state->range_sizek, chunk_sizek);
    + if ((range0_sizek == state->range_sizek) ||
    + ((range0_basek + range0_sizek > basek) && basek)) {
    + printk(KERN_INFO "rangeX: %016lx - %016lx\n", range0_basek<<10, (range0_basek + range0_sizek)<<10);
    + state->reg = range_to_mtrr(state->reg, range0_basek,
    + range0_sizek, next_basek, MTRR_TYPE_WRBACK, state->address_bits);
    + return;
    + }
    +
    + range0_sizek -= chunk_sizek;
    + range_basek = range0_basek + range0_sizek;
    + printk(KERN_INFO "range0: %016lx - %016lx\n", range0_basek<<10, (range0_basek + range0_sizek)<<10);
    + state->reg = range_to_mtrr(state->reg, range0_basek,
    + range0_sizek, range_basek, MTRR_TYPE_WRBACK, state->address_bits);
    +
    + range_sizek = chunk_sizek;
    + if (range_sizek - (state->range_sizek - range0_sizek) < (chunk_sizek >> 1)) {
    + hole_sizek = range_sizek - (state->range_sizek - range0_sizek);
    + next_basek = hole_basek = range_basek + range_sizek - hole_sizek;
    + } else {
    + range_sizek = state->range_sizek - range0_sizek;
    + }
    + printk(KERN_INFO "range: %016lx - %016lx\n", range_basek<<10, (range_basek + range_sizek)<<10);
    + state->reg = range_to_mtrr(state->reg, range_basek,
    + range_sizek, next_basek, MTRR_TYPE_WRBACK, state->address_bits);
    + if (hole_sizek) {
    + printk(KERN_INFO "hole: %016lx - %016lx\n", hole_basek<<10, (hole_basek + hole_sizek)<<10);
    + state->reg = range_to_mtrr(state->reg, hole_basek,
    + hole_sizek, basek, MTRR_TYPE_UNCACHABLE, state->address_bits);
    + }
    +}
    +
    +static void __init set_var_mtrr_range(struct var_mtrr_state *state, size_t base_pfn, size_t size_pfn)
    +{
    + unsigned long basek, sizek;
    +
    + if (state->reg >= num_var_ranges)
    + return;
    +
    + basek = base_pfn << (PAGE_SHIFT - 10);
    + sizek = size_pfn << (PAGE_SHIFT - 10);
    +
    + /* See if I can merge with the last range */
    + if ((basek <= 1024) || (state->range_startk + state->range_sizek == basek)) {
    + unsigned long endk = basek + sizek;
    + state->range_sizek = endk - state->range_startk;
    + return;
    + }
    + /* Write the range mtrrs */
    + if (state->range_sizek != 0) {
    + range_to_mtrr_with_hole(state, basek);
    +
    + state->range_startk = 0;
    + state->range_sizek = 0;
    + }
    + /* Allocate an msr */
    + state->range_startk = basek;
    + state->range_sizek = sizek;
    +}
    +
    +static u64 mtrr_chunk_size __initdata = (256ULL<<20);
    +
    +static int __init parse_mtrr_chunk_size_opt(char *p)
    +{
    + if (!p)
    + return -EINVAL;
    + mtrr_chunk_size = memparse(p, &p);
    + return 0;
    +}
    +early_param("mtrr_chunk_size", parse_mtrr_chunk_size_opt);
    +
    +static void __init x86_setup_var_mtrrs(struct res_range *range, int nr_range, unsigned address_bits)
    +{
    + struct var_mtrr_state var_state;
    + int i;
    +
    + var_state.range_startk = 0;
    + var_state.range_sizek = 0;
    + var_state.reg = 0;
    + var_state.address_bits = address_bits;
    + var_state.chunk_sizek = mtrr_chunk_size >> 10;
    +
    + /* Write the range etc */
    + for (i = 0; i < nr_range; i++)
    + set_var_mtrr_range(&var_state, range[i].start, range[i].end - range[i].start + 1);
    +
    + /* Write the last range */
    + range_to_mtrr_with_hole(&var_state, 0);
    + printk(KERN_INFO "DONE variable MTRRs\n");
    + /* Clear out the extra MTRR's */
    + while (var_state.reg < num_var_ranges)
    + set_var_mtrr(var_state.reg++, 0, 0, 0, var_state.address_bits);
    +}
    +
    +static int __init mtrr_cleanup(unsigned address_bits)
    +{
    + unsigned long i, base, size, def, dummy;
    + mtrr_type type;
    + struct res_range range[RANGE_NUM];
    + int nr_range;
    +
    + /* extra one for all 0 */
    + int num[MTRR_NUM_TYPES + 1];
    +
    + if (!is_cpu(INTEL) || disable_mtrr_cleanup)
    + return 0;
    + rdmsr(MTRRdefType_MSR, def, dummy);
    + def &= 0xff;
    + if (def != MTRR_TYPE_UNCACHABLE)
    + return 0;
    +
    + /* check entries number */
    + memset(num, 0, sizeof(num));
    + for (i = 0; i < num_var_ranges; i++) {
    + mtrr_if->get(i, &base, &size, &type);
    + if (type >= MTRR_NUM_TYPES)
    + continue;
    + if (!size)
    + type = MTRR_NUM_TYPES;
    + num[type]++;
    + }
    +
    + /* check if we got UC entries */
    + if (!num[MTRR_TYPE_UNCACHABLE])
    + return 0;
    +
    + /* check if we only had WB and UC */
    + if (num[MTRR_TYPE_WRBACK] + num[MTRR_TYPE_UNCACHABLE] !=
    + num_var_ranges - num[MTRR_NUM_TYPES])
    + return 0;
    +
    + /*
    + * get WB ranges at first
    + * assume BIOS don't give us overlapping WB entries
    + * or add add_range?
    + */
    + memset(range, 0, sizeof(range));
    + nr_range = 0;
    + for (i = 0; i < num_var_ranges; i++) {
    + mtrr_if->get(i, &base, &size, &type);
    + if (type != MTRR_TYPE_WRBACK)
    + continue;
    + range[nr_range].start = base;
    + range[nr_range].end = base + size - 1;
    + nr_range++;
    + }
    + printk(KERN_INFO "After WB checking\n");
    + for (i = 0; i < nr_range; i++)
    + printk(KERN_INFO "MTRR MAP PFN: %016lx - %016lx\n", range[i].start, range[i].end + 1);
    +
    + /* take out UC ranges */
    + for (i = 0; i < num_var_ranges; i++) {
    + mtrr_if->get(i, &base, &size, &type);
    + if (type != MTRR_TYPE_UNCACHABLE)
    + continue;
    + if (!size)
    + continue;
    + subtract_range(range, base, base + size - 1);
    + }
    + /* get new range num */
    + nr_range = 0;
    + for (i = 0; i < RANGE_NUM; i++) {
    + if (!range[i].end)
    + continue;
    + nr_range++;
    + }
    + printk(KERN_INFO "After UC checking\n");
    + for (i = 0; i < nr_range; i++)
    + printk(KERN_INFO "MTRR MAP PFN: %016lx - %016lx\n", range[i].start, range[i].end + 1);
    +
    + /* sort the ranges */
    + sort(range, nr_range, sizeof(struct res_range), cmp_range, NULL);
    + printk(KERN_INFO "After sorting\n");
    + for (i = 0; i < nr_range; i++)
    + printk(KERN_INFO "MTRR MAP PFN: %016lx - %016lx\n", range[i].start, range[i].end + 1);
    +
    + /* convert ranges to var ranges state */
    + x86_setup_var_mtrrs(range, nr_range, address_bits);
    +
    + return 1;
    +
    +}
    +
    static int disable_mtrr_trim;

    static int __init disable_mtrr_trim_setup(char *str)
    @@ -729,18 +1072,21 @@ int __init mtrr_trim_uncached_memory(uns
    */
    void __init mtrr_bp_init(void)
    {
    + u32 phys_addr;
    init_ifs();

    + phys_addr = 32;
    +
    if (cpu_has_mtrr) {
    mtrr_if = &generic_mtrr_ops;
    size_or_mask = 0xff000000; /* 36 bits */
    size_and_mask = 0x00f00000;
    + phys_addr = 36;

    /* This is an AMD specific MSR, but we assume(hope?) that
    Intel will implement it to when they extend the address
    bus of the Xeon. */
    if (cpuid_eax(0x80000000) >= 0x80000008) {
    - u32 phys_addr;
    phys_addr = cpuid_eax(0x80000008) & 0xff;
    /* CPUID workaround for Intel 0F33/0F34 CPU */
    if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL &&
    @@ -758,6 +1104,7 @@ void __init mtrr_bp_init(void)
    don't support PAE */
    size_or_mask = 0xfff00000; /* 32 bits */
    size_and_mask = 0;
    + phys_addr = 32;
    }
    } else {
    switch (boot_cpu_data.x86_vendor) {
    @@ -791,8 +1138,13 @@ void __init mtrr_bp_init(void)
    if (mtrr_if) {
    set_num_var_ranges();
    init_table();
    - if (use_intel())
    + if (use_intel()) {
    get_mtrr_state();
    +
    + if (mtrr_cleanup(phys_addr))
    + mtrr_if->set_all();
    +
    + }
    }
    }

    Index: linux-2.6/arch/x86/kernel/cpu/mtrr/mtrr.h
    ===================================================================
    --- linux-2.6.orig/arch/x86/kernel/cpu/mtrr/mtrr.h
    +++ linux-2.6/arch/x86/kernel/cpu/mtrr/mtrr.h
    @@ -81,6 +81,8 @@ void set_mtrr_done(struct set_mtrr_conte
    void set_mtrr_cache_disable(struct set_mtrr_context *ctxt);
    void set_mtrr_prepare_save(struct set_mtrr_context *ctxt);

    +void fill_mtrr_var_range(unsigned int index,
    + u32 base_lo, u32 base_hi, u32 mask_lo, u32 mask_hi);
    void get_mtrr_state(void);

    extern void set_mtrr_ops(struct mtrr_ops * ops);
    Index: linux-2.6/Documentation/kernel-parameters.txt
    ===================================================================
    --- linux-2.6.orig/Documentation/kernel-parameters.txt
    +++ linux-2.6/Documentation/kernel-parameters.txt
    @@ -595,6 +595,16 @@ and is between 256 and 4096 characters.
    See drivers/char/README.epca and
    Documentation/digiepca.txt.

    + disable_mtrr_cleanup [X86]
    + By default the kernel will adjust mtrr from continuous
    + to discrete layout, to make x server driver could add
    + WB entry later. This parameter disables that behavior,
    + will not touch MTRRs.
    +
    + mtrr_chunk_size=nn[KMG] [X86]
    + used for mtrr cleanup. It is largest continous chunk
    + that could hold holes aka. UC entries.
    +
    disable_mtrr_trim [X86, Intel and AMD only]
    By default the kernel will trim any uncacheable
    memory out of your available memory pool based on

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