On 09/11/2015 12:54, Huaitong Han wrote: > The protection-key feature provides an additional mechanism by which IA-32e > paging controls access to usermode addresses. > > Hardware support for protection keys for user pages is enumerated with CPUID > feature flag CPUID.7.0.ECX[3]:PKU. Software support is CPUID.7.0.ECX[4]:OSPKE > with the setting of CR4.PKE(bit 22). > > When CR4.PKE = 1, every linear address is associated with the 4-bit protection > key located in bits 62:59 of the paging-structure entry that mapped the page > containing the linear address. The PKRU register determines, for each > protection key, whether user-mode addresses with that protection key may be > read or written. > > The PKRU register (protection key rights for user pages) is a 32-bit register > with the following format: for each i (0 ≤ i ≤ 15), PKRU[2i] is the > access-disable bit for protection key i (ADi); PKRU[2i+1] is the write-disable > bit for protection key i (WDi). > > Software can use the RDPKRU and WRPKRU instructions with ECX = 0 to read and > write PKRU. In addition, the PKRU register is XSAVE-managed state and can thus > be read and written by instructions in the XSAVE feature set. Hi, this looks more or less okay. I made a few comments on the individual patches. Please add a test for PKRU to kvm-unit-tests' access.c. I will _not_ merge this feature without unit tests. I have merged nested VPID without, and it was a mistake because they were never submitted and probably never will. Thanks, Paolo -- 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
