Messages in this thread | | | From | Peter Maydell <> | Date | Thu, 7 Jan 2016 15:58:15 +0000 | Subject | Re: [Qemu-devel] arm64 qemu tests failing in linux-next since 'arm64: kernel: enforce pmuserenr_el0 initialization and restore' |
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On 7 January 2016 at 15:53, Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> wrote: > On Thu, Jan 07, 2016 at 01:25:35PM +0000, Peter Maydell wrote: >> We had previously been relying on the kernel not attempting to >> touch the PMU if the ID_AA64DFR0_EL1 PMUVer bits read 0000 >> ("Performance Monitors extension System registers not implemented"). > > Ok, thanks for looking into this. I wonder why reading pmcr_el0 does > not suffer from the same problem though.
Just a pragmatic thing on QEMU's end, I expect -- the kernel already touched PMCR_EL0 and we wanted to be able to boot it, so we have an implementation of it.
thanks -- PMM
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