Nitin A Kamble wrote: > Hi Avi, > I find that the qemu processor reset state is not per the IA32 > processor specifications. (Sections 8.1.1 of > http://www.intel.com/Assets/PDF/manual/253668.pdf) > > In qemu-kvm.git in file target-i386/helper.c in function cpu_reset the > segment registers are initialized as follows: > > cpu_x86_load_seg_cache(env, R_CS, 0xf000, 0xffff0000, 0xffff, > DESC_P_MASK | DESC_S_MASK | DESC_CS_MASK | > DESC_R_MASK); > cpu_x86_load_seg_cache(env, R_DS, 0, 0, 0xffff, > DESC_P_MASK | DESC_S_MASK | DESC_W_MASK); > cpu_x86_load_seg_cache(env, R_ES, 0, 0, 0xffff, > DESC_P_MASK | DESC_S_MASK | DESC_W_MASK); > cpu_x86_load_seg_cache(env, R_SS, 0, 0, 0xffff, > DESC_P_MASK | DESC_S_MASK | DESC_W_MASK); > cpu_x86_load_seg_cache(env, R_FS, 0, 0, 0xffff, > DESC_P_MASK | DESC_S_MASK | DESC_W_MASK); > cpu_x86_load_seg_cache(env, R_GS, 0, 0, 0xffff, > DESC_P_MASK | DESC_S_MASK | DESC_W_MASK); > > While the IA32 cpu reset state specification says that Segment Accessed > bit is also 1 at the time of cpu reset. so the above code should look > like this: > > cpu_x86_load_seg_cache(env, R_CS, 0xf000, 0xffff0000, 0xffff, > DESC_P_MASK | DESC_S_MASK | DESC_CS_MASK | > DESC_R_MASK | DESC_A_MASK); > cpu_x86_load_seg_cache(env, R_DS, 0, 0, 0xffff, > DESC_P_MASK | DESC_S_MASK | DESC_W_MASK | DESC_A_MASK); > cpu_x86_load_seg_cache(env, R_ES, 0, 0, 0xffff, > DESC_P_MASK | DESC_S_MASK | DESC_W_MASK| DESC_A_MASK); > cpu_x86_load_seg_cache(env, R_SS, 0, 0, 0xffff, > DESC_P_MASK | DESC_S_MASK | DESC_W_MASK |DESC_A_MASK); > cpu_x86_load_seg_cache(env, R_FS, 0, 0, 0xffff, > DESC_P_MASK | DESC_S_MASK | DESC_W_MASK); > cpu_x86_load_seg_cache(env, R_GS, 0, 0, 0xffff, > DESC_P_MASK | DESC_S_MASK | DESC_W_MASK); > > This discrepancy is adding the need of the following function in the > unrestricted guest patch.
As Avi already indicated: Independent of the kvm workaround for older qemu versions, please post (to qemu-devel) a patch against upstream's git to fix the discrepancy. Jan -- Siemens AG, Corporate Technology, CT SE 2 Corporate Competence Center Embedded Linux -- 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
