On 07/26/2012 05:20 PM, Takuya Yoshikawa wrote: > On Thu, 26 Jul 2012 11:56:15 +0300 > Avi Kivity <avi@xxxxxxxxxx> wrote: > >> Since my comments are better done as a separate patch, I applied all >> three patches. Thanks! > > Is this patch really safe for all architectures? > > IS_ERR_VALUE() casts -MAX_ERRNO to unsigned long and then does comparison. > Isn't it possible to conflict with valid pfns? > See IS_ERR_VALUE(): #define IS_ERR_VALUE(x) unlikely((x) >= (unsigned long)-MAX_ERRNO) The minimal value of the error code is: 0xffff f001 on 32-bit and 0x ffff ffff ffff f001 on 64-bit, it is fair larger that a valid pfn (for the pfn, the most top of 12 bits are always 0). Note, PAE is a special case, but only 64G physical memory is valid, 0xffff f001 is also suitable for that. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
