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. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
