Re: [PATCH v5 04/11] common: add vmtrace_pt_size domain parameter

From: "Michał Leszczyński" <michal.leszczynski@cert.pl>
To: xen-devel@lists.xenproject.org
Cc: Julien Grall <julien@xen.org>,
	Stefano Stabellini <sstabellini@kernel.org>,
	luwei kang <luwei.kang@intel.com>, Wei Liu <wl@xen.org>,
	Andrew Cooper <andrew.cooper3@citrix.com>,
	Ian Jackson <ian.jackson@eu.citrix.com>,
	George Dunlap <george.dunlap@citrix.com>,
	Jan Beulich <jbeulich@suse.com>,
	tamas lengyel <tamas.lengyel@intel.com>
Subject: Re: [PATCH v5 04/11] common: add vmtrace_pt_size domain parameter
Date: Mon, 6 Jul 2020 12:13:21 +0200 (CEST)	[thread overview]
Message-ID: <2097446473.20028399.1594030401534.JavaMail.zimbra@cert.pl> (raw)
In-Reply-To: <5d52b37e391a4165dc3775f77a621d34a33d22c2.1593974333.git.michal.leszczynski@cert.pl>

----- 5 lip 2020 o 20:54, Michał Leszczyński michal.leszczynski@cert.pl napisał(a):

> From: Michal Leszczynski <michal.leszczynski@cert.pl>
> 
> Add vmtrace_pt_size domain parameter in live domain and
> vmtrace_pt_order parameter in xen_domctl_createdomain.
> 
> Signed-off-by: Michal Leszczynski <michal.leszczynski@cert.pl>
> ---
> xen/common/domain.c         | 12 ++++++++++++
> xen/include/public/domctl.h |  1 +
> xen/include/xen/sched.h     |  4 ++++
> 3 files changed, 17 insertions(+)
> 
> diff --git a/xen/common/domain.c b/xen/common/domain.c
> index a45cf023f7..25d3359c5b 100644
> --- a/xen/common/domain.c
> +++ b/xen/common/domain.c
> @@ -338,6 +338,12 @@ static int sanitise_domain_config(struct
> xen_domctl_createdomain *config)
>         return -EINVAL;
>     }
> 
> +    if ( config->vmtrace_pt_order && !vmtrace_supported )
> +    {
> +        dprintk(XENLOG_INFO, "Processor tracing is not supported\n");
> +        return -EINVAL;
> +    }
> +
>     return arch_sanitise_domain_config(config);
> }
> 
> @@ -443,6 +449,12 @@ struct domain *domain_create(domid_t domid,
>         d->nr_pirqs = min(d->nr_pirqs, nr_irqs);
> 
>         radix_tree_init(&d->pirq_tree);
> +
> +        if ( config->vmtrace_pt_order )
> +        {
> +            uint32_t shift_val = config->vmtrace_pt_order + PAGE_SHIFT;
> +            d->vmtrace_pt_size = (1ULL << shift_val);
> +        }
>     }
> 
>     if ( (err = arch_domain_create(d, config)) != 0 )
> diff --git a/xen/include/public/domctl.h b/xen/include/public/domctl.h
> index 59bdc28c89..7b8289d436 100644
> --- a/xen/include/public/domctl.h
> +++ b/xen/include/public/domctl.h
> @@ -92,6 +92,7 @@ struct xen_domctl_createdomain {
>     uint32_t max_evtchn_port;
>     int32_t max_grant_frames;
>     int32_t max_maptrack_frames;
> +    uint8_t vmtrace_pt_order;
> 
>     struct xen_arch_domainconfig arch;
> };
> diff --git a/xen/include/xen/sched.h b/xen/include/xen/sched.h
> index ac53519d7f..48f0a61bbd 100644
> --- a/xen/include/xen/sched.h
> +++ b/xen/include/xen/sched.h
> @@ -457,6 +457,10 @@ struct domain
>     unsigned    pbuf_idx;
>     spinlock_t  pbuf_lock;
> 
> +    /* Used by vmtrace features */
> +    spinlock_t  vmtrace_lock;
> +    uint64_t    vmtrace_pt_size;
> +
>     /* OProfile support. */
>     struct xenoprof *xenoprof;
> 
> --
> 2.17.1

Just a note to myself: in v4 it was suggested by Jan that we should
go with "number of kB" instead of "number of bytes" and the type
could be uint32_t.

I will modify it in such way within the next version.

Best regards,
Michał Leszczyński
CERT Polska