From: "Roger Pau Monné" <roger.pau@citrix.com>
To: "Michał Leszczyński" <michal.leszczynski@cert.pl>
Cc: Kevin Tian <kevin.tian@intel.com>,
Stefano Stabellini <sstabellini@kernel.org>,
Julien Grall <julien@xen.org>,
Jun Nakajima <jun.nakajima@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 K Lengyel <tamas.k.lengyel@gmail.com>,
Xen-devel <xen-devel@lists.xenproject.org>
Subject: Re: [PATCH v1 0/7] Implement support for external IPT monitoring
Date: Thu, 18 Jun 2020 10:25:39 +0200 [thread overview]
Message-ID: <20200618082539.GE735@Air-de-Roger> (raw)
In-Reply-To: <1348695738.9265003.1592425220928.JavaMail.zimbra@cert.pl>
On Wed, Jun 17, 2020 at 10:20:20PM +0200, Michał Leszczyński wrote:
> ----- 17 cze 2020 o 18:19, Andrew Cooper andrew.cooper3@citrix.com napisał(a):
>
> > On 17/06/2020 04:02, Tamas K Lengyel wrote:
> >> On Tue, Jun 16, 2020 at 2:17 PM Andrew Cooper <andrew.cooper3@citrix.com> wrote:
> >>> On 16/06/2020 19:47, Michał Leszczyński wrote:
> >>>> ----- 16 cze 2020 o 20:17, Andrew Cooper andrew.cooper3@citrix.com napisał(a):
> >>>>
> >>>>> Are there any restrictions on EPT being enabled in the first place? I'm
> >>>>> not aware of any, and in principle we could use this functionality for
> >>>>> PV guests as well (using the CPL filter). Therefore, I think it would
> >>>>> be helpful to not tie the functionality to HVM guests, even if that is
> >>>>> the only option enabled to start with.
> >>>> I think at the moment it's not required to have EPT. This patch series doesn't
> >>>> use any translation feature flags, so the output address is always a machine
> >>>> physical address, regardless of context. I will check if it could be easily
> >>>> used with PV.
> >>> If its trivial to add PV support then please do. If its not, then don't
> >>> feel obliged, but please do at least consider how PV support might look
> >>> in the eventual feature.
> >>>
> >>> (Generally speaking, considering "how would I make this work in other
> >>> modes where it is possible" leads to a better design.)
> >>>
> >>>>> The buffer mapping and creation logic is fairly problematic. Instead of
> >>>>> fighting with another opencoded example, take a look at the IOREQ
> >>>>> server's use of "acquire resource" which is a mapping interface which
> >>>>> supports allocating memory on behalf of the guest, outside of the guest
> >>>>> memory, for use by control tools.
> >>>>>
>
>
> One thing that remains unclear to me is the "acquire resource" part. Could you give some more details on that?
>
> Assuming that buffers are allocated right from the domain creation, what mechanism (instead of xc_map_foreign_range) should I use to map the IPT buffers into Dom0?
Take a look at demu's demu_initialize function [0] (and it's usage of
xenforeignmemory_map_resource), you likely need something similar for
the trace buffers, introducing a new XENMEM_resource_trace_data kind
of resource (naming subject to change), and use the id field in
xen_mem_acquire_resource to signal which vCPU buffer you want to
map.
That's usable by both PV and HVM guests.
Roger.
[0] http://xenbits.xen.org/gitweb/?p=people/pauldu/demu.git;a=blob;f=demu.c;h=f785b394d0cf141dffa05bdddecf338214358aea;hb=refs/heads/master#l453
next prev parent reply other threads:[~2020-06-18 8:26 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-16 15:16 [PATCH v1 0/7] Implement support for external IPT monitoring Michał Leszczyński
2020-06-16 15:19 ` [PATCH v1 1/7] x86/vmx: add Intel PT MSR definitions Michał Leszczyński
2020-06-18 13:31 ` Jan Beulich
2020-06-16 15:20 ` [PATCH v1 2/7] x86/vmx: add IPT cpu feature Michał Leszczyński
2020-06-16 16:30 ` Roger Pau Monné
2020-06-17 11:34 ` Jan Beulich
2020-06-16 15:21 ` [PATCH v1 3/7] x86/vmx: add ipt_state as part of vCPU state Michał Leszczyński
2020-06-16 16:33 ` Roger Pau Monné
2020-06-16 15:22 ` [PATCH v1 4/7] x86/vmx: add do_vmtrace_op Michał Leszczyński
2020-06-16 17:23 ` Roger Pau Monné
2020-06-17 19:13 ` Michał Leszczyński
2020-06-18 3:20 ` Tamas K Lengyel
2020-06-18 11:01 ` Michał Leszczyński
2020-06-18 11:55 ` Roger Pau Monné
2020-06-18 12:51 ` Jan Beulich
2020-06-18 13:09 ` Michał Leszczyński
2020-06-18 13:24 ` Jan Beulich
2020-06-18 13:40 ` Roger Pau Monné
2020-06-18 8:46 ` Roger Pau Monné
2020-06-18 15:25 ` Michał Leszczyński
2020-06-18 15:39 ` Jan Beulich
2020-06-18 15:47 ` Tamas K Lengyel
2020-06-18 15:49 ` Tamas K Lengyel
2020-06-16 15:22 ` [PATCH v1 5/7] tools/libxc: add xc_ptbuf_* functions Michał Leszczyński
2020-06-16 15:23 ` [PATCH v1 6/7] tools/proctrace: add proctrace tool Michał Leszczyński
2020-06-16 15:24 ` [PATCH v1 7/7] x86/vmx: switch IPT MSRs on vmentry/vmexit Michał Leszczyński
2020-06-16 17:38 ` Roger Pau Monné
2020-06-16 17:47 ` Michał Leszczyński
2020-06-17 9:09 ` Roger Pau Monné
2020-06-17 11:54 ` Michał Leszczyński
2020-06-17 12:51 ` Roger Pau Monné
2020-06-17 15:14 ` Andrew Cooper
2020-06-17 18:56 ` Michał Leszczyński
2020-06-18 8:52 ` Roger Pau Monné
2020-06-18 11:07 ` Michał Leszczyński
2020-06-18 11:49 ` Roger Pau Monné
2020-06-17 23:30 ` Kang, Luwei
2020-06-18 10:02 ` Andrew Cooper
2020-06-18 17:38 ` Andrew Cooper
2020-06-16 18:17 ` [PATCH v1 0/7] Implement support for external IPT monitoring Andrew Cooper
2020-06-16 18:47 ` Michał Leszczyński
2020-06-16 20:16 ` Andrew Cooper
2020-06-17 3:02 ` Tamas K Lengyel
2020-06-17 16:19 ` Andrew Cooper
2020-06-17 16:27 ` Tamas K Lengyel
2020-06-17 17:23 ` Andrew Cooper
2020-06-17 19:31 ` Tamas K Lengyel
2020-06-17 19:30 ` Michał Leszczyński
2020-06-17 20:20 ` Michał Leszczyński
2020-06-18 8:25 ` Roger Pau Monné [this message]
2020-06-18 14:59 ` Michał Leszczyński
2020-06-17 1:35 ` Tian, Kevin
2020-06-17 6:45 ` Kang, Luwei
2020-06-17 9:21 ` Roger Pau Monné
2020-06-17 12:37 ` Kang, Luwei
2020-06-17 12:53 ` Roger Pau Monné
2020-06-17 23:29 ` Kang, Luwei
2020-06-18 0:56 ` Michał Leszczyński
2020-06-18 7:00 ` Roger Pau Monné
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