On 02/25/2010 07:15 PM, Joerg Roedel wrote:
The algorithm to find the offset in the msrpm for a given
msr is needed at other places too. Move that logic to its
own function.
#define MAX_INST_SIZE 15
@@ -417,23 +439,22 @@ err_1:
static void set_msr_interception(u32 *msrpm, unsigned msr,
int read, int write)
{
- int i;
+ u8 bit_read, bit_write;
+ unsigned long tmp;
+ u32 offset;
- for (i = 0; i< NUM_MSR_MAPS; i++) {
- if (msr>= msrpm_ranges[i]&&
- msr< msrpm_ranges[i] + MSRS_IN_RANGE) {
- u32 msr_offset = (i * MSRS_IN_RANGE + msr -
- msrpm_ranges[i]) * 2;
-
- u32 *base = msrpm + (msr_offset / 32);
- u32 msr_shift = msr_offset % 32;
- u32 mask = ((write) ? 0 : 2) | ((read) ? 0 : 1);
- *base = (*base& ~(0x3<< msr_shift)) |
- (mask<< msr_shift);
- return;
- }
- }
- BUG();
+ offset = svm_msrpm_offset(msr);
+ bit_read = 2 * (msr& 0x0f);
+ bit_write = 2 * (msr& 0x0f) + 1;
+
+ BUG_ON(offset == MSR_INVALID);
+
+ tmp = msrpm[offset];
+
+ read ? clear_bit(bit_read,&tmp) : set_bit(bit_read,&tmp);
+ write ? clear_bit(bit_write,&tmp) : set_bit(bit_write,&tmp);
+
+ msrpm[offset] = tmp;
}
This can fault - set_bit() accesses an unsigned long, which can be 8
bytes, while offset can point into the last u32 of msrpm. So this needs
either to revert to u32 shift/mask ops or msrpm be changed to a ulong
array (actually better, since bitmaps in general are defined as arrays
of ulongs).
btw, the op-level ternary expression is terrible, relying solely on
*_bit()'s side effects. Please convert to an ordinary if.
btw2, use __set_bit() which atomic operation is not needed.
--
Do not meddle in the internals of kernels, for they are subtle and quick to panic.
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