From: Andrew Cooper <andrew.cooper3@citrix.com>
To: Jan Beulich <JBeulich@suse.com>
Cc: Stefano Stabellini <sstabellini@kernel.org>,
Wei Liu <wei.liu2@citrix.com>,
George Dunlap <George.Dunlap@eu.citrix.com>,
Ian Jackson <Ian.Jackson@eu.citrix.com>, Tim Deegan <tim@xen.org>,
Paul Durrant <paul.durrant@citrix.com>,
xen-devel <xen-devel@lists.xenproject.org>,
dgdegra@tycho.nsa.gov
Subject: Re: [PATCH 01/11] public / x86: introduce hvmctl hypercall
Date: Thu, 23 Jun 2016 16:35:02 +0100 [thread overview]
Message-ID: <c90b4d77-9b79-471b-447e-f1dea5d9ad0b@citrix.com> (raw)
In-Reply-To: <576C180702000078000F82BE@prv-mh.provo.novell.com>
On 23/06/16 16:10, Jan Beulich wrote:
>>>> On 23.06.16 at 16:55, <andrew.cooper3@citrix.com> wrote:
>> On 20/06/16 13:52, Jan Beulich wrote:
>>> +/*
>>> + * Note that this value is effectively part of the ABI, even if we don't
>> need
>>> + * to make it a formal part of it. Hence this value may only be changed if
>>> + * accompanied by a suitable interface version increase.
>>> + */
>>> +#define HVMCTL_iter_shift 8
>>> +#define HVMCTL_iter_mask ((1U << HVMCTL_iter_shift) - 1)
>>> +#define HVMCTL_iter_max (1U << (16 + HVMCTL_iter_shift))
>> This (mis)use of the cmd parameter is surely no longer necessary, given
>> that there is space in xen_hvmctl_t to encode continuation information?
> There's no misuse of cmd anymore. This is just use to make the 16-bit
> continuation value (the opaque structure member) cover a more useful
> range, and at once avoid doing the preemption check on every
> iteration.
Ah ok, but it does leave the minimum iteration at 256, which could
easily be too large, depending on the underlying operation.
In this case, I think it would be far better to bump the cmd field to 32
bits, and opaque to 64bits, which affords us far more flexibility.
~Andrew
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next prev parent reply other threads:[~2016-06-23 15:35 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-20 12:39 [PATCH 00/11] hvmctl hypercall Jan Beulich
2016-06-20 12:52 ` [PATCH 01/11] public / x86: introduce " Jan Beulich
2016-06-21 10:14 ` Wei Liu
2016-06-23 14:55 ` Andrew Cooper
2016-06-23 15:10 ` Jan Beulich
2016-06-23 15:35 ` Andrew Cooper [this message]
2016-06-20 12:53 ` [PATCH 02/11] hvmctl: convert HVMOP_set_pci_intx_level Jan Beulich
2016-06-20 14:32 ` Daniel De Graaf
2016-06-20 14:48 ` Ian Jackson
2016-06-20 15:25 ` Jan Beulich
2016-06-21 10:14 ` Wei Liu
2016-06-20 12:53 ` [PATCH 03/11] hvmctl: convert HVMOP_set_isa_irq_level Jan Beulich
2016-06-21 10:14 ` Wei Liu
2016-06-20 12:54 ` [PATCH 04/11] hvmctl: convert HVMOP_set_pci_link_route Jan Beulich
2016-06-21 10:14 ` Wei Liu
2016-06-20 12:54 ` [PATCH 05/11] hvmctl: convert HVMOP_track_dirty_vram Jan Beulich
2016-06-21 10:14 ` Wei Liu
2016-06-20 12:55 ` [PATCH 06/11] hvmctl: convert HVMOP_modified_memory Jan Beulich
2016-06-21 10:14 ` Wei Liu
2016-06-20 12:56 ` [PATCH 07/11] hvmctl: convert HVMOP_set_mem_type Jan Beulich
2016-06-21 10:14 ` Wei Liu
2016-06-20 12:56 ` [PATCH 08/11] hvmctl: convert HVMOP_inject_trap Jan Beulich
2016-06-21 10:14 ` Wei Liu
2016-06-20 12:57 ` [PATCH 09/11] hvmctl: convert HVMOP_inject_msi Jan Beulich
2016-06-21 10:14 ` Wei Liu
2016-06-20 12:57 ` [PATCH 10/11] hvmctl: convert HVMOP_*ioreq_server* Jan Beulich
2016-06-21 10:14 ` Wei Liu
2016-06-21 12:44 ` Paul Durrant
2016-06-20 12:58 ` [PATCH 11/11] x86/HVM: serialize trap injecting producer and consumer Jan Beulich
2016-06-23 15:14 ` Andrew Cooper
2016-06-23 15:15 ` [PATCH 00/11] hvmctl hypercall Andrew Cooper
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