[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH 1/2] x86/VPMU: Support only versions 2 and 3 of architectural performance monitoring
On 12/01/2015 04:01 AM, Dietmar Hahn wrote: Am Montag 30 November 2015, 13:38:40 schrieb Boris Ostrovsky:We need to have at least version 2 since it's the first version to support various control and status registers (such as MSR_CORE_PERF_GLOBAL_CTRL) that VPMU relies on always having. With explicit testing for PMU version we can now remove CPUID model check. Signed-off-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx> --- xen/arch/x86/cpu/vpmu_intel.c | 55 +++++++------------------------------------ 1 file changed, 8 insertions(+), 47 deletions(-) diff --git a/xen/arch/x86/cpu/vpmu_intel.c b/xen/arch/x86/cpu/vpmu_intel.c index d5ea7fe..bb4ddcc 100644 --- a/xen/arch/x86/cpu/vpmu_intel.c +++ b/xen/arch/x86/cpu/vpmu_intel.c @@ -955,59 +955,20 @@ int vmx_vpmu_initialise(struct vcpu *v) int __init core2_vpmu_init(void) { u64 caps; + unsigned int version = 0;- if ( current_cpu_data.x86 != 6 )+ if ( current_cpu_data.cpuid_level >= 0xa ) + version = cpuid_eax(0xa) & 0xff; + if ( (version != 2) && (version != 3) ) { - printk(XENLOG_WARNING "VPMU: only family 6 is supported\n"); + printk(XENLOG_WARNING "VPMU: version %d is not supported\n", version); return -EINVAL;But this means that all (newer?) processors with version=4 are not supported even though the SDM 3B tells: "Processors supporting architectural performance monitoring version 4 also supports version 1, 2, and 3, ..." Shold we not only write a hint that version 4 capabilities are not supported and fake this cpuid-flag for the guests to the version 3? I in fact didn't know there was version 4 since I've always been looking at (apparently) old version of the SDM (Jan 2013). We should indeed then downgrade version 4 to 3 as reported by .do_cpud() op. -boris _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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