From: Jan Beulich <jbeulich@suse.com>
To: "Roger Pau Monné" <roger.pau@citrix.com>
Cc: "xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>,
Paul Durrant <paul@xen.org>,
Andrew Cooper <andrew.cooper3@citrix.com>,
George Dunlap <george.dunlap@citrix.com>,
Ian Jackson <iwj@xenproject.org>, Julien Grall <julien@xen.org>,
Stefano Stabellini <sstabellini@kernel.org>, Wei Liu <wl@xen.org>
Subject: Re: [PATCH v2 12/18] AMD/IOMMU: allow use of superpage mappings
Date: Mon, 13 Dec 2021 09:49:50 +0100 [thread overview]
Message-ID: <d472fbb5-95f3-dc6b-8103-e7d76e71290a@suse.com> (raw)
In-Reply-To: <YbNtBPv1M1lIyEOd@Air-de-Roger>
On 10.12.2021 16:06, Roger Pau Monné wrote:
> On Fri, Sep 24, 2021 at 11:52:14AM +0200, Jan Beulich wrote:
>> ---
>> I'm not fully sure about allowing 512G mappings: The scheduling-for-
>> freeing of intermediate page tables can take quite a while when
>> replacing a tree of 4k mappings by a single 512G one. Plus (or otoh)
>> there's no present code path via which 512G chunks of memory could be
>> allocated (and hence mapped) anyway.
>
> I would limit to 1G, which is what we support for CPU page tables
> also.
I'm not sure I buy comparing with CPU side support when not sharing
page tables. Not the least with PV in mind.
>> @@ -288,10 +289,31 @@ static int iommu_pde_from_dfn(struct dom
>> return 0;
>> }
>>
>> +static void queue_free_pt(struct domain *d, mfn_t mfn, unsigned int next_level)
>
> Nit: should the last parameter be named level rather than next_level?
> AFAICT it's the level of the mfn parameter.
Yeah, might make sense.
> Should we also assert that level (or next_level) is always != 0 for
> extra safety?
As said elsewhere - if this wasn't a static helper, I'd agree. But all
call sites have respective conditionals around the call. If anything
I'd move those checks into the function (but only if you think that
would improve things, as to me having them at the call sites is more
logical).
Jan
next prev parent reply other threads:[~2021-12-13 8:50 UTC|newest]
Thread overview: 100+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-24 9:39 [PATCH v2 00/18] IOMMU: superpage support when not sharing pagetables Jan Beulich
2021-09-24 9:41 ` [PATCH v2 01/18] AMD/IOMMU: have callers specify the target level for page table walks Jan Beulich
2021-09-24 10:58 ` Roger Pau Monné
2021-09-24 12:02 ` Jan Beulich
2021-09-24 9:42 ` [PATCH v2 02/18] VT-d: " Jan Beulich
2021-09-24 14:45 ` Roger Pau Monné
2021-09-27 9:04 ` Jan Beulich
2021-09-27 9:13 ` Jan Beulich
2021-11-30 11:56 ` Roger Pau Monné
2021-11-30 14:38 ` Jan Beulich
2021-09-24 9:43 ` [PATCH v2 03/18] IOMMU: have vendor code announce supported page sizes Jan Beulich
2021-11-30 12:25 ` Roger Pau Monné
2021-12-17 14:43 ` Julien Grall
2021-12-21 9:26 ` Rahul Singh
2021-09-24 9:44 ` [PATCH v2 04/18] IOMMU: add order parameter to ->{,un}map_page() hooks Jan Beulich
2021-11-30 13:49 ` Roger Pau Monné
2021-11-30 14:45 ` Jan Beulich
2021-12-17 14:42 ` Julien Grall
2021-09-24 9:45 ` [PATCH v2 05/18] IOMMU: have iommu_{,un}map() split requests into largest possible chunks Jan Beulich
2021-11-30 15:24 ` Roger Pau Monné
2021-12-02 15:59 ` Jan Beulich
2021-09-24 9:46 ` [PATCH v2 06/18] IOMMU/x86: restrict IO-APIC mappings for PV Dom0 Jan Beulich
2021-12-01 9:09 ` Roger Pau Monné
2021-12-01 9:27 ` Jan Beulich
2021-12-01 10:32 ` Roger Pau Monné
2021-12-01 11:45 ` Jan Beulich
2021-12-02 15:12 ` Roger Pau Monné
2021-12-02 15:28 ` Jan Beulich
2021-12-02 19:16 ` Andrew Cooper
2021-12-03 6:41 ` Jan Beulich
2021-09-24 9:47 ` [PATCH v2 07/18] IOMMU/x86: perform PV Dom0 mappings in batches Jan Beulich
2021-12-02 14:10 ` Roger Pau Monné
2021-12-03 12:38 ` Jan Beulich
2021-12-10 9:36 ` Roger Pau Monné
2021-12-10 11:41 ` Jan Beulich
2021-12-10 12:35 ` Roger Pau Monné
2021-09-24 9:48 ` [PATCH v2 08/18] IOMMU/x86: support freeing of pagetables Jan Beulich
2021-12-02 16:03 ` Roger Pau Monné
2021-12-02 16:10 ` Jan Beulich
2021-12-03 8:30 ` Roger Pau Monné
2021-12-03 9:38 ` Roger Pau Monné
2021-12-03 9:40 ` Jan Beulich
2021-12-10 13:51 ` Roger Pau Monné
2021-12-13 8:38 ` Jan Beulich
2021-09-24 9:48 ` [PATCH v2 09/18] AMD/IOMMU: drop stray TLB flush Jan Beulich
2021-12-02 16:16 ` Roger Pau Monné
2021-09-24 9:51 ` [PATCH v2 10/18] AMD/IOMMU: walk trees upon page fault Jan Beulich
2021-12-03 9:03 ` Roger Pau Monné
2021-12-03 9:49 ` Jan Beulich
2021-12-03 9:55 ` Jan Beulich
2021-12-10 10:23 ` Roger Pau Monné
2021-12-03 9:59 ` Jan Beulich
2021-09-24 9:51 ` [PATCH v2 11/18] AMD/IOMMU: return old PTE from {set,clear}_iommu_pte_present() Jan Beulich
2021-12-10 12:05 ` Roger Pau Monné
2021-12-10 12:59 ` Jan Beulich
2021-12-10 13:53 ` Roger Pau Monné
2021-09-24 9:52 ` [PATCH v2 12/18] AMD/IOMMU: allow use of superpage mappings Jan Beulich
2021-12-10 15:06 ` Roger Pau Monné
2021-12-13 8:49 ` Jan Beulich [this message]
2021-12-13 9:45 ` Roger Pau Monné
2021-12-13 10:00 ` Jan Beulich
2021-12-13 10:33 ` Roger Pau Monné
2021-12-13 10:41 ` Jan Beulich
2021-09-24 9:52 ` [PATCH v2 13/18] VT-d: " Jan Beulich
2021-12-13 11:54 ` Roger Pau Monné
2021-12-13 13:39 ` Jan Beulich
2021-09-24 9:53 ` [PATCH v2 14/18] IOMMU: fold flush-all hook into "flush one" Jan Beulich
2021-12-13 15:04 ` Roger Pau Monné
2021-12-14 9:06 ` Jan Beulich
2021-12-14 9:27 ` Roger Pau Monné
2021-12-15 15:28 ` Oleksandr
2021-12-16 8:49 ` Jan Beulich
2021-12-16 10:39 ` Oleksandr
2021-12-16 11:30 ` Rahul Singh
2021-12-21 8:04 ` Jan Beulich
2021-12-17 14:38 ` Julien Grall
2021-09-24 9:54 ` [PATCH v2 15/18] IOMMU/x86: prefill newly allocate page tables Jan Beulich
2021-12-13 15:51 ` Roger Pau Monné
2021-12-14 9:15 ` Jan Beulich
2021-12-14 11:41 ` Roger Pau Monné
2021-12-14 11:48 ` Jan Beulich
2021-12-14 14:50 ` Roger Pau Monné
2021-12-14 15:05 ` Jan Beulich
2021-12-14 15:15 ` Roger Pau Monné
2021-12-14 15:21 ` Jan Beulich
2021-12-14 15:06 ` Roger Pau Monné
2021-12-14 15:10 ` Jan Beulich
2021-12-14 15:17 ` Roger Pau Monné
2021-12-14 15:24 ` Jan Beulich
2021-09-24 9:55 ` [PATCH v2 16/18] x86: introduce helper for recording degree of contiguity in " Jan Beulich
2021-12-15 13:57 ` Roger Pau Monné
2021-12-16 15:47 ` Jan Beulich
2021-12-20 15:25 ` Roger Pau Monné
2021-12-21 8:09 ` Jan Beulich
2022-01-04 8:57 ` Roger Pau Monné
2022-01-04 9:00 ` Jan Beulich
2021-09-24 9:55 ` [PATCH v2 17/18] AMD/IOMMU: free all-empty " Jan Beulich
2021-12-15 15:14 ` Roger Pau Monné
2021-12-16 15:54 ` Jan Beulich
2021-09-24 9:56 ` [PATCH v2 18/18] VT-d: " Jan Beulich
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