[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH V6 03/10] xen/arm: Use the new functions for vCPUID/vaffinity transformation
On Fri, 2015-06-05 at 19:18 +0100, Julien Grall wrote: > On 05/06/2015 16:56, Ian Campbell wrote: > > On Mon, 2015-06-01 at 20:56 +0800, Chen Baozi wrote: > >> From: Chen Baozi <baozich@xxxxxxxxx> > >> > >> There are 3 places to change: > >> > >> * Initialise vMPIDR value in vcpu_initialise() > >> * Find the vCPU from vMPIDR affinity information when accessing GICD > >> registers in vGIC > >> * Find the vCPU from vMPIDR affinity information when booting with vPSCI > >> in vGIC > >> - Also make the code for PSCI 0.1 use MPIDR-like value as the cpuid. > > > > Does this "- Also ..." not need to be done at the same time as the > > change to how we describe things in the FDT? Since that is where the > > guest gets the parameter from, isn't it? > > Well, we only support 8 CPUs. I was assuming this would change later in the patch. I don't think PSCI 0.1 is limited to gic v2, is it? (If it is then this is worth mentioning in the commit message too) > So this changes will return the same value > as before. It may be worth to mention it. > > In another side, both PSCI 0.1 and PSCI 0.2 are modified to respect the > MPIDR like within this patch. The working in the commit message may be > misleading. Yes, possibly. > Somehow the code path slightly differ when the PSCI 0.2 for guest has > been added. The spec says (PSCI 0.1 Section 6.3 (ARM DEN 0022A)): > > "Ideally platform discovery mechanism such as firmware tables would be > used by secure firmware to describe the set of valid CPUIDs to the > hypervisor or Rich OS, if the former is not present. The hypervisor in > turn can create and supply virtual discovery mechanisms to its guests."" > > I interpreted this as CPUID is equal to the "reg" register in DT (which > is an MPIDR-like value). > > FWIW, this is the interpretation made by Linux too. Documentation/devicetree/bindings/arm/cpus.txt requires it to be the MPIDR value on armv7 and v8. Ian. _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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