[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v4 2/6] microcode: save all microcodes which pass sanity check
>>> On 29.11.18 at 03:40, <chao.gao@xxxxxxxxx> wrote: > On Wed, Nov 28, 2018 at 01:00:14PM +0100, Roger Pau Monné wrote: >>On Wed, Nov 28, 2018 at 01:34:12PM +0800, Chao Gao wrote: >>> @@ -491,6 +559,21 @@ static int cpu_request_microcode(unsigned int cpu, >>> const void *buf, >>> while ( (error = get_ucode_from_buffer_amd(mc_amd, buf, bufsize, >>> &offset)) == 0 ) >>> { >>> + struct ucode_patch *ucode_patch; >>> + >>> + /* >>> + * Save this microcode before checking the signature. It is to >>> + * optimize microcode update on a mixed family system. Parsing >> >>Er, is it possible to have a system with CPUs of different family? >>What's going to happen with CPUs having different features? > > I have no idea. That each cpu has a per-cpu variable to store the > microcode rather than a global one gives me a feeling that the current > implementation wants to make it work on a system with CPUs of different > family. I think we've long given up on supporting mixed-model or even mixed-family systems. Therefore in this overhaul doing away with per-CPU tracking beyond the present ucode level (which indeed may differ, even if we may have to consider to refuse keeping the system up in such a case) would perhaps be pretty reasonable. One thing definitely needs to work: Updating of ucode when firmware has loaded differing versions (which usually boils down to firmware neglecting to load ucode on all cores). Jan _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxxx https://lists.xenproject.org/mailman/listinfo/xen-devel
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