[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v15 11/21] x86/VPMU: Interface for setting PMU mode and flags
On 12/04/2014 03:51 AM, Jan Beulich wrote: On 03.12.14 at 21:13, <boris.ostrovsky@xxxxxxxxxx> wrote:On 11/27/2014 03:57 AM, Jan Beulich wrote:On 26.11.14 at 15:32, <boris.ostrovsky@xxxxxxxxxx> wrote:On 11/25/2014 08:49 AM, Jan Beulich wrote:On 17.11.14 at 00:07, <boris.ostrovsky@xxxxxxxxxx> wrote:@@ -244,19 +256,19 @@ void vpmu_initialise(struct vcpu *v) switch ( vendor ) { case X86_VENDOR_AMD: - if ( svm_vpmu_initialise(v, opt_vpmu_enabled) != 0 ) - opt_vpmu_enabled = 0; + if ( svm_vpmu_initialise(v) != 0 ) + vpmu_mode = XENPMU_MODE_OFF; break;case X86_VENDOR_INTEL:- if ( vmx_vpmu_initialise(v, opt_vpmu_enabled) != 0 ) - opt_vpmu_enabled = 0; + if ( vmx_vpmu_initialise(v) != 0 ) + vpmu_mode = XENPMU_MODE_OFF; break;So this turns off the vPMU globally upon failure of initializing some random vCPU. Why is that? I see this was the case even before your entire series, but shouldn't this be fixed _before_ enhancing the whole thing to support PV/PVH?Yes, that's probably too strong. Do you want to fix this as an early patch (before PV(H)) support gets in? I'd rather do it in the patch that moves things into initcalls.Yes, I think this should be fixed in a prereq patch, thus allowing it to be easily backported if so desired.I started to make this change and then I realized that the next patch (12/21) is actually already taking care of this problem: most of the *_vpmu_initialise() will be executed as initcalls during host boot and if any of those fail then we do want to disable VPMU globally (those failures would not be VCPU-specific).Funny that you say that - it was actually while reviewing that next patch when I made that observation: svm_vpmu_initialise() get a -ENOMEM return _added_ there for example, which is contrary to what I asked for above. Oh, *that* initialization code (I was looking at vpmu_init()). Yes, VPMU should not be turned off there. -boris _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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