We need to use the size_and_mask in set_mtrr_var_ranges(which is called 
while programming MTRR's for AP's

Signed-off-by: Suresh Siddha <[EMAIL PROTECTED]>

--- linux/arch/i386/kernel/cpu/mtrr/generic.c~  2005-04-10 14:07:11.821466664 
-0700
+++ linux/arch/i386/kernel/cpu/mtrr/generic.c   2005-04-10 14:12:21.913325536 
-0700
@@ -192,7 +192,8 @@ static int set_mtrr_var_ranges(unsigned 
 
        rdmsr(MTRRphysBase_MSR(index), lo, hi);
        if ((vr->base_lo & 0xfffff0ffUL) != (lo & 0xfffff0ffUL)
-           || (vr->base_hi & 0xfUL) != (hi & 0xfUL)) {
+           || (vr->base_hi & (size_and_mask >> (32 - PAGE_SHIFT))) != 
+               (hi & (size_and_mask >> (32 - PAGE_SHIFT)))) {
                mtrr_wrmsr(MTRRphysBase_MSR(index), vr->base_lo, vr->base_hi);
                changed = TRUE;
        }
@@ -200,7 +201,8 @@ static int set_mtrr_var_ranges(unsigned 
        rdmsr(MTRRphysMask_MSR(index), lo, hi);
 
        if ((vr->mask_lo & 0xfffff800UL) != (lo & 0xfffff800UL)
-           || (vr->mask_hi & 0xfUL) != (hi & 0xfUL)) {
+           || (vr->mask_hi & (size_and_mask >> (32 - PAGE_SHIFT))) != 
+               (hi & (size_and_mask >> (32 - PAGE_SHIFT)))) {
                mtrr_wrmsr(MTRRphysMask_MSR(index), vr->mask_lo, vr->mask_hi);
                changed = TRUE;
        }

On Thu, Apr 07, 2005 at 05:42:36PM +0200, Andi Kleen wrote:
> Always use CPUID 80000008 to figure out MTRR address space size
> 
> It doesn't make sense to only do this only for AMD K8.
> 
> This would support future CPUs with extended address spaces properly.
> 
> For i386 and x86-64
> 
> Cc: [EMAIL PROTECTED]
> 
> 
> Index: linux/arch/i386/kernel/cpu/mtrr/main.c
> ===================================================================
> --- linux.orig/arch/i386/kernel/cpu/mtrr/main.c
> +++ linux/arch/i386/kernel/cpu/mtrr/main.c
> @@ -614,40 +614,21 @@ static int __init mtrr_init(void)
>               mtrr_if = &generic_mtrr_ops;
>               size_or_mask = 0xff000000;      /* 36 bits */
>               size_and_mask = 0x00f00000;
> -                     
> -             switch (boot_cpu_data.x86_vendor) {
> -             case X86_VENDOR_AMD:
> -                     /* The original Athlon docs said that
> -                        total addressable memory is 44 bits wide.
> -                        It was not really clear whether its MTRRs
> -                        follow this or not. (Read: 44 or 36 bits).
> -                        However, "x86-64_overview.pdf" explicitly
> -                        states that "previous implementations support
> -                        36 bit MTRRs" and also provides a way to
> -                        query the width (in bits) of the physical
> -                        addressable memory on the Hammer family.
> -                      */
> -                     if (boot_cpu_data.x86 == 15
> -                         && (cpuid_eax(0x80000000) >= 0x80000008)) {
> -                             u32 phys_addr;
> -                             phys_addr = cpuid_eax(0x80000008) & 0xff;
> -                             size_or_mask =
> -                                 ~((1 << (phys_addr - PAGE_SHIFT)) - 1);
> -                             size_and_mask = ~size_or_mask & 0xfff00000;
> -                     }
> -                     /* Athlon MTRRs use an Intel-compatible interface for 
> -                      * getting and setting */
> -                     break;
> -             case X86_VENDOR_CENTAUR:
> -                     if (boot_cpu_data.x86 == 6) {
> -                             /* VIA Cyrix family have Intel style MTRRs, but 
> don't support PAE */
> -                             size_or_mask = 0xfff00000;      /* 32 bits */
> -                             size_and_mask = 0;
> -                     }
> -                     break;
> -             
> -             default:
> -                     break;
> +     
> +             /* 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;
> +                     size_or_mask = ~((1 << (phys_addr - PAGE_SHIFT)) - 1);
> +                     size_and_mask = ~size_or_mask & 0xfff00000;
> +             } else if (boot_cpu_data.x86_vendor == X86_VENDOR_CENTAUR &&
> +                        boot_cpu_data.x86 == 6) {
> +                     /* VIA C* family have Intel style MTRRs, but
> +                        don't support PAE */
> +                     size_or_mask = 0xfff00000;      /* 32 bits */
> +                     size_and_mask = 0;
>               }
>       } else {
>               switch (boot_cpu_data.x86_vendor) {
-
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