From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Jan Beulich" <JBeulich@suse.com>
Subject: Re: [PATCH v9 17/20] x86/VPMU: Add privileged PMU mode
Date: Tue, 12 Aug 2014 14:06:46 +0100
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References: <1407516946-17833-1-git-send-email-boris.ostrovsky@oracle.com>
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To: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: kevin.tian@intel.com, keir@xen.org, suravee.suthikulpanit@amd.com, andrew.cooper3@citrix.com, tim@xen.org, xen-devel@lists.xen.org, jun.nakajima@intel.com
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>>> On 08.08.14 at 18:55, <boris.ostrovsky@oracle.com> wrote:
> @@ -192,32 +199,65 @@ int vpmu_do_interrupt(struct cpu_user_regs *regs)
>          vpmu->arch_vpmu_ops->arch_vpmu_save(sampling);
>          vpmu_reset(vpmu, VPMU_CONTEXT_SAVE | VPMU_CONTEXT_LOADED);
>  
> -        /* Store appropriate registers in xenpmu_data */
> -        if ( is_pv_32bit_domain(sampled->domain) )
> +        if ( !is_hvm_domain(sampled->domain) )

I agree with using "sampled" here.

>          {
> -            /*
> -             * 32-bit dom0 cannot process Xen's addresses (which are 64 bit)
> -             * and therefore we treat it the same way as a non-priviledged
> -             * PV 32-bit domain.
> -             */
> -            struct compat_cpu_user_regs *cmp;
> -
> -            gregs = guest_cpu_user_regs();
> -
> -            cmp = (void *)&vpmu->xenpmu_data->pmu.r.regs;
> -            XLAT_cpu_user_regs(cmp, gregs);
> +            /* Store appropriate registers in xenpmu_data */
> +            if ( is_pv_32bit_domain(sampled->domain) )

But why is this not "sampling"? The layout of the data you present
should depend on the consumer of the data

> +            {
> +                /*
> +                 * 32-bit dom0 cannot process Xen's addresses (which are 64 bit)
> +                 * and therefore we treat it the same way as a non-priviledged

non-privileged

> +                 * PV 32-bit domain.
> +                 */
> +                struct compat_cpu_user_regs *cmp;
> +
> +                gregs = guest_cpu_user_regs();
> +
> +                cmp = (void *)&vpmu->xenpmu_data->pmu.r.regs;
> +                XLAT_cpu_user_regs(cmp, gregs);
> +
> +                /* Adjust RPL for kernel mode */
> +                if ((cmp->cs & 3) == 1)
> +                    cmp->cs &= ~3;
> +            }

Jan