From: Jan Beulich <jbeulich@suse.com>
To: Julien Grall <julien@xen.org>
Cc: "Kevin Tian" <kevin.tian@intel.com>,
"Stefano Stabellini" <sstabellini@kernel.org>,
tamas.lengyel@intel.com, "Wei Liu" <wl@xen.org>,
"Andrew Cooper" <andrew.cooper3@citrix.com>,
"Michał Leszczyński" <michal.leszczynski@cert.pl>,
"Ian Jackson" <ian.jackson@eu.citrix.com>,
"George Dunlap" <george.dunlap@citrix.com>,
"Jun Nakajima" <jun.nakajima@intel.com>,
xen-devel@lists.xenproject.org, luwei.kang@intel.com,
"Roger Pau Monné" <roger.pau@citrix.com>
Subject: Re: [PATCH v4 02/10] x86/vmx: add IPT cpu feature
Date: Thu, 2 Jul 2020 11:18:22 +0200 [thread overview]
Message-ID: <0e02a9b5-ba7a-43a2-3369-a4410f216ddb@suse.com> (raw)
In-Reply-To: <3fa0c3e7-9243-b1bb-d6ad-a3bd21437782@xen.org>
On 02.07.2020 10:54, Julien Grall wrote:
>
>
> On 02/07/2020 09:50, Jan Beulich wrote:
>> On 02.07.2020 10:42, Julien Grall wrote:
>>> On 02/07/2020 09:29, Jan Beulich wrote:
>>>> I'm with Andrew here, fwiw, as long as the little bit of code that
>>>> is actually put in common/ or include/xen/ doesn't imply arbitrary
>>>> restrictions on acceptable values.
>>> Well yes the code is simple. However, the code as it is wouldn't be
>>> usuable on other architecture without additional work (aside arch
>>> specific code). For instance, there is no way to map the buffer outside
>>> of Xen as it is all x86 specific.
>>>
>>> If you want the allocation to be in the common code, then the
>>> infrastructure to map/unmap the buffer should also be in common code.
>>> Otherwise, there is no point to allocate it in common.
>>
>> I don't think I agree here - I see nothing wrong with exposing of
>> the memory being arch specific, when allocation is generic. This
>> is no different from, in just x86, allocation logic being common
>> to PV and HVM, but exposing being different for both.
>
> Are you suggesting that the way it would be exposed may be different for
> other architecture?
Why not? To take a possibly extreme example - consider an arch
where (for bare metal) the buffer is specified to appear at a
fixed range of addresses. This would then want to be this way
in the virtualized case as well. There'd be no point in using
any common logic mapping the buffer at a guest requested
address. Instead it would simply appear at the arch mandated
one, without the guest needing to take any action.
> If so, this is one more reason to not impose a way for allocating the
> buffer in the common code until another arch add support for vmtrace.
I'm still not seeing why allocation and exposure need to be done
at the same place.
Jan
next prev parent reply other threads:[~2020-07-02 9:18 UTC|newest]
Thread overview: 75+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-30 12:33 [PATCH v4 00/10] Implement support for external IPT monitoring Michał Leszczyński
2020-06-30 12:33 ` [PATCH v4 01/10] x86/vmx: add Intel PT MSR definitions Michał Leszczyński
2020-06-30 16:23 ` Jan Beulich
2020-06-30 17:37 ` Andrew Cooper
2020-06-30 18:03 ` Tamas K Lengyel
2020-06-30 18:27 ` Michał Leszczyński
2020-07-01 17:52 ` Andrew Cooper
2020-06-30 12:33 ` [PATCH v4 02/10] x86/vmx: add IPT cpu feature Michał Leszczyński
2020-07-01 9:49 ` Roger Pau Monné
2020-07-01 15:12 ` Julien Grall
2020-07-01 16:06 ` Andrew Cooper
2020-07-01 16:17 ` Julien Grall
2020-07-01 16:18 ` Julien Grall
2020-07-01 17:26 ` Andrew Cooper
2020-07-01 18:02 ` Julien Grall
2020-07-01 18:06 ` Andrew Cooper
2020-07-01 18:09 ` Julien Grall
2020-07-02 8:29 ` Jan Beulich
2020-07-02 8:42 ` Julien Grall
2020-07-02 8:50 ` Jan Beulich
2020-07-02 8:54 ` Julien Grall
2020-07-02 9:18 ` Jan Beulich [this message]
2020-07-02 9:57 ` Julien Grall
2020-07-02 13:30 ` Jan Beulich
2020-07-02 14:14 ` Julien Grall
2020-07-02 14:17 ` Jan Beulich
2020-07-02 14:31 ` Julien Grall
2020-07-02 20:28 ` Michał Leszczyński
2020-07-03 7:58 ` Julien Grall
2020-07-04 19:16 ` Michał Leszczyński
2020-07-01 21:42 ` Andrew Cooper
2020-07-02 8:10 ` Roger Pau Monné
2020-07-02 8:34 ` Jan Beulich
2020-07-02 20:29 ` Michał Leszczyński
2020-06-30 12:33 ` [PATCH v4 03/10] tools/libxl: add vmtrace_pt_size parameter Michał Leszczyński
2020-07-01 10:05 ` Roger Pau Monné
2020-07-02 9:00 ` Roger Pau Monné
2020-07-02 16:23 ` Michał Leszczyński
2020-07-03 9:44 ` Roger Pau Monné
2020-07-03 9:56 ` Jan Beulich
2020-07-03 10:11 ` Roger Pau Monné
2020-07-04 17:23 ` Julien Grall
2020-07-06 8:46 ` Jan Beulich
2020-07-07 8:44 ` Julien Grall
2020-07-07 9:10 ` Jan Beulich
2020-07-07 9:16 ` Julien Grall
2020-07-07 11:17 ` Michał Leszczyński
2020-07-07 11:21 ` Jan Beulich
2020-07-07 11:35 ` Michał Leszczyński
2020-07-02 10:24 ` Anthony PERARD
2020-07-04 17:48 ` Julien Grall
2020-06-30 12:33 ` [PATCH v4 04/10] x86/vmx: implement processor tracing for VMX Michał Leszczyński
2020-07-01 10:30 ` Roger Pau Monné
2020-06-30 12:33 ` [PATCH v4 05/10] common/domain: allocate vmtrace_pt_buffer Michał Leszczyński
2020-07-01 10:38 ` Roger Pau Monné
2020-07-01 15:35 ` Julien Grall
2020-06-30 12:33 ` [PATCH v4 06/10] memory: batch processing in acquire_resource() Michał Leszczyński
2020-07-01 10:46 ` Roger Pau Monné
2020-07-03 10:35 ` Julien Grall
2020-07-03 10:52 ` Paul Durrant
2020-07-03 11:17 ` Julien Grall
2020-07-03 11:22 ` Jan Beulich
2020-07-03 11:36 ` Julien Grall
2020-07-03 12:50 ` Jan Beulich
2020-07-03 11:40 ` Paul Durrant
2020-06-30 12:33 ` [PATCH v4 07/10] x86/mm: add vmtrace_buf resource type Michał Leszczyński
2020-07-01 10:52 ` Roger Pau Monné
2020-06-30 12:33 ` [PATCH v4 08/10] x86/domctl: add XEN_DOMCTL_vmtrace_op Michał Leszczyński
2020-07-01 11:00 ` Roger Pau Monné
2020-06-30 12:33 ` [PATCH v4 09/10] tools/libxc: add xc_vmtrace_* functions Michał Leszczyński
2020-07-21 10:52 ` Wei Liu
2020-06-30 12:33 ` [PATCH v4 10/10] tools/proctrace: add proctrace tool Michał Leszczyński
2020-07-02 15:10 ` Andrew Cooper
2020-07-21 10:52 ` Wei Liu
2020-06-30 12:48 ` [PATCH v4 00/10] Implement support for external IPT monitoring Hubert Jasudowicz
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