From: Julien Grall <julien.grall@arm.com>
To: Jan Beulich <jbeulich@suse.com>, Paul Durrant <paul.durrant@citrix.com>
Cc: "Kevin Tian" <kevin.tian@intel.com>,
"Stefano Stabellini" <sstabellini@kernel.org>,
"Jun Nakajima" <jun.nakajima@intel.com>, "Wei Liu" <wl@xen.org>,
"George Dunlap" <george.dunlap@eu.citrix.com>,
VolodymyrBabchuk <Volodymyr_Babchuk@epam.com>,
"Suravee Suthikulpanit" <suravee.suthikulpanit@amd.com>,
"Andrew Cooper" <andrew.cooper3@citrix.com>,
xen-devel@lists.xenproject.org,
"Brian Woods" <brian.woods@amd.com>,
"Roger Pau Monné" <roger.pau@citrix.com>
Subject: Re: [Xen-devel] [PATCH 2/6] use is_iommu_enabled() where appropriate...
Date: Wed, 7 Aug 2019 11:22:25 +0100 [thread overview]
Message-ID: <217d7fd7-f5bf-3e0c-a553-aa9539c35607@arm.com> (raw)
In-Reply-To: <d96b7a8b-4668-576f-84d2-e0a382d86c87@suse.com>
Hi Jan,
On 07/08/2019 10:55, Jan Beulich wrote:
> On 30.07.2019 15:44, Paul Durrant wrote:
>> --- a/xen/arch/arm/p2m.c
>> +++ b/xen/arch/arm/p2m.c
>> @@ -1531,8 +1531,7 @@ int p2m_init(struct domain *d)
>> * shared with the CPU, Xen has to make sure that the PT changes have
>> * reached the memory
>> */
>> - p2m->clean_pte = iommu_enabled &&
>> - !iommu_has_feature(d, IOMMU_FEAT_COHERENT_WALK);
>> + p2m->clean_pte = !iommu_has_feature(d, IOMMU_FEAT_COHERENT_WALK);
>
> I can't tell if the original code was meant to be this way, but I'm
> afraid your transformation is not correct: The prior construct,
> expanding iommu_has_feature(), was
The original code is meant to be this way. There are no need to clean the PTE on
update unless you have one IOMMU that is not able to snoop the cache.
iommu_has_feature(...) will return false when the IOMMU is not in use. The
iommu_enabled prevent to clean PTE on those setups.
Cheers,
--
Julien Grall
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next prev parent reply other threads:[~2019-08-07 10:22 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-30 13:44 [Xen-devel] [PATCH 0/6] per-domain IOMMU control Paul Durrant
2019-07-30 13:44 ` [Xen-devel] [PATCH 1/6] domain: introduce XEN_DOMCTL_CDF_iommu Paul Durrant
2019-08-07 9:21 ` Jan Beulich
2019-08-12 12:22 ` Paul Durrant
2019-07-30 13:44 ` [Xen-devel] [PATCH 2/6] use is_iommu_enabled() where appropriate Paul Durrant
2019-08-07 9:55 ` Jan Beulich
2019-08-07 10:22 ` Julien Grall [this message]
2019-08-12 14:53 ` Paul Durrant
2019-07-30 13:44 ` [Xen-devel] [PATCH 3/6] remove late (on-demand) construction of IOMMU page tables Paul Durrant
2019-08-01 8:05 ` Alexandru Stefan ISAILA
2019-08-07 10:31 ` Jan Beulich
2019-08-12 15:41 ` Paul Durrant
2019-08-12 16:26 ` Paul Durrant
2019-08-14 9:39 ` Paul Durrant
2019-08-27 7:48 ` Jan Beulich
2019-08-29 9:33 ` Paul Durrant
2019-08-29 9:52 ` Jan Beulich
2019-08-29 10:20 ` Paul Durrant
2019-08-29 10:33 ` Jan Beulich
2019-08-27 7:47 ` Jan Beulich
2019-08-27 7:45 ` Jan Beulich
2019-08-29 9:28 ` Paul Durrant
2019-07-30 13:44 ` [Xen-devel] [PATCH 4/6] make passthrough/pci.c:deassign_device() static Paul Durrant
2019-08-06 15:54 ` Jan Beulich
2019-08-14 9:42 ` Paul Durrant
2019-07-30 13:44 ` [Xen-devel] [PATCH 5/6] iommu: tidy up iommu_us_hap_pt() and need_iommu_pt_sync() macros Paul Durrant
2019-08-07 10:41 ` Jan Beulich
2019-08-14 10:13 ` Paul Durrant
2019-08-14 10:20 ` Julien Grall
2019-08-14 10:27 ` Paul Durrant
2019-08-14 10:44 ` Julien Grall
2019-08-14 11:11 ` Paul Durrant
2019-08-14 12:28 ` Julien Grall
2019-08-14 12:35 ` Paul Durrant
2019-08-27 7:53 ` Jan Beulich
2019-07-30 13:44 ` [Xen-devel] [PATCH 6/6] introduce a 'passthrough' configuration option to xl.cfg Paul Durrant
2019-08-07 12:12 ` Jan Beulich
2019-08-14 10:40 ` Paul Durrant
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