Re: [PATCH 01/11] x86/fault: Fix AMD erratum #91 errata fixup for user code

2021-02-01 Thread Borislav Petkov
On Sun, Jan 31, 2021 at 09:24:32AM -0800, Andy Lutomirski wrote: > The recent rework of probe_kernel_read() and its conversion to Judging by 25f12ae45fc1 ("maccess: rename probe_kernel_address to get_kernel_nofault") I think you mean probe_kernel_address() above and below. > get_kernel_nofaul

Re: [PATCH 01/11] x86/fault: Fix AMD erratum #91 errata fixup for user code

2021-02-01 Thread Christoph Hellwig
On Sun, Jan 31, 2021 at 09:24:32AM -0800, Andy Lutomirski wrote: > While we're at it, disable the workaround on all CPUs except AMD Family > 0xF. By my reading of the Revision Guide for AMD Athlon™ 64 and AMD > Opteron™ Processors, only family 0xF is affected. I think it would be better to have o

[PATCH 01/11] x86/fault: Fix AMD erratum #91 errata fixup for user code

2021-01-31 Thread Andy Lutomirski
The recent rework of probe_kernel_read() and its conversion to get_kernel_nofault() inadvertently broke is_prefetch(). We were using probe_kernel_read() as a sloppy "read user or kernel memory" helper, but it doens't do that any more. The new get_kernel_nofault() reads *kernel* memory only, which