From: George Dunlap <George.Dunlap@eu.citrix.com>
To: Tiejun Chen <tiejun.chen@intel.com>
Cc: Kevin Tian <kevin.tian@intel.com>, Keir Fraser <keir@xen.org>,
Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>,
Andrew Cooper <andrew.cooper3@citrix.com>,
Tim Deegan <tim@xen.org>,
"xen-devel@lists.xen.org" <xen-devel@lists.xen.org>,
Aravind Gopalakrishnan <Aravind.Gopalakrishnan@amd.com>,
Jan Beulich <jbeulich@suse.com>,
Yang Zhang <yang.z.zhang@intel.com>,
Stefano Stabellini <stefano.stabellini@citrix.com>,
Ian Campbell <ian.campbell@citrix.com>
Subject: Re: [v7][PATCH 03/16] xen/passthrough: extend hypercall to support rdm reservation policy
Date: Fri, 10 Jul 2015 14:26:19 +0100 [thread overview]
Message-ID: <CAFLBxZbZkS3ZRyTC-g07MYNCDDm4Tb3rCB2oJRzx3qVHxxEvPA@mail.gmail.com> (raw)
In-Reply-To: <1436420047-25356-4-git-send-email-tiejun.chen@intel.com>
On Thu, Jul 9, 2015 at 6:33 AM, Tiejun Chen <tiejun.chen@intel.com> wrote:
> This patch extends the existing hypercall to support rdm reservation policy.
> We return error or just throw out a warning message depending on whether
> the policy is "strict" or "relaxed" when reserving RDM regions in pfn space.
> Note in some special cases, e.g. add a device to hwdomain, and remove a
> device from user domain, 'relaxed' is fine enough since this is always safe
> to hwdomain.
>
> CC: Tim Deegan <tim@xen.org>
> CC: Keir Fraser <keir@xen.org>
> CC: Jan Beulich <jbeulich@suse.com>
> CC: Andrew Cooper <andrew.cooper3@citrix.com>
> CC: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
> CC: Aravind Gopalakrishnan <Aravind.Gopalakrishnan@amd.com>
> CC: Ian Campbell <ian.campbell@citrix.com>
> CC: Stefano Stabellini <stefano.stabellini@citrix.com>
> CC: Yang Zhang <yang.z.zhang@intel.com>
> CC: Kevin Tian <kevin.tian@intel.com>
> Signed-off-by: Tiejun Chen <tiejun.chen@intel.com>
> ---
> v6 ~ v7:
>
> * Nothing is changed.
>
> v5:
>
> * Just leave one bit XEN_DOMCTL_DEV_RDM_RELAXED as our flag, so
> "0" means "strict" and "1" means "relaxed".
Thanks for this; a few more comments...
> @@ -1577,9 +1578,15 @@ int iommu_do_pci_domctl(
> seg = machine_sbdf >> 16;
> bus = PCI_BUS(machine_sbdf);
> devfn = PCI_DEVFN2(machine_sbdf);
> + flag = domctl->u.assign_device.flag;
> + if ( flag > XEN_DOMCTL_DEV_RDM_RELAXED )
This is not a blocker, but a stylistic comment: I would have inverted
the bitmask here, as that's conceptually what you're checking. I
won't make this a blocker for going in.
> @@ -1898,7 +1899,14 @@ static int intel_iommu_add_device(u8 devfn, struct pci_dev *pdev)
> PCI_BUS(bdf) == pdev->bus &&
> PCI_DEVFN2(bdf) == devfn )
> {
> - ret = rmrr_identity_mapping(pdev->domain, 1, rmrr);
> + /*
> + * Here means we're add a device to the hardware domain
> + * so actually RMRR is always reserved on e820 so either
> + * of flag is fine for hardware domain and here we'd like
> + * to pass XEN_DOMCTL_DEV_RDM_RELAXED.
> + */
Sorry I didn't give feedback on your comment before. I don't find it
clear enough; I'd suggest something like this:
"iommu_add_device() is only called for the hardware domain (see
xen/drivers/passthrough/pci.c:pci_add_device()). Since RMRRs are
always reserved in the e820 map for the hardware domain, there
shouldn't be a conflict."
I also said that if we went with anything other than STRICT that we'd
need to check to make sure that the domain really was the hardware
domain before proceeding, in case the assumption that pdev->domain ==
hardware_domain ever changed. (Perhaps with an ASSERT -- Jan, what do
you think?)
Also, passing in RELAXED in locations where the flag is completely
ignored (such as when removing mappings) doesn't really make any
sense.
On the whole I think it would be better if you removed the RELAXED
flag for both removals and for hardware domains.
-George
next prev parent reply other threads:[~2015-07-10 13:26 UTC|newest]
Thread overview: 119+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-09 5:33 [v7][PATCH 00/16] Fix RMRR Tiejun Chen
2015-07-09 5:33 ` [v7][PATCH 01/16] xen: introduce XENMEM_reserved_device_memory_map Tiejun Chen
2015-07-09 5:33 ` [v7][PATCH 02/16] xen/vtd: create RMRR mapping Tiejun Chen
2015-07-09 5:33 ` [v7][PATCH 03/16] xen/passthrough: extend hypercall to support rdm reservation policy Tiejun Chen
2015-07-10 13:26 ` George Dunlap [this message]
2015-07-10 15:01 ` Jan Beulich
2015-07-10 15:07 ` George Dunlap
2015-07-13 6:37 ` Chen, Tiejun
2015-07-13 5:57 ` Chen, Tiejun
2015-07-13 6:47 ` Chen, Tiejun
2015-07-13 8:57 ` Jan Beulich
2015-07-14 10:46 ` George Dunlap
2015-07-14 10:53 ` Chen, Tiejun
2015-07-14 11:30 ` George Dunlap
2015-07-14 11:45 ` Jan Beulich
2015-07-14 13:25 ` George Dunlap
2015-07-09 5:33 ` [v7][PATCH 04/16] xen: enable XENMEM_memory_map in hvm Tiejun Chen
2015-07-09 5:33 ` [v7][PATCH 05/16] hvmloader: get guest memory map into memory_map[] Tiejun Chen
2015-07-10 13:49 ` George Dunlap
2015-07-13 7:03 ` Chen, Tiejun
2015-07-09 5:33 ` [v7][PATCH 06/16] hvmloader/pci: skip reserved ranges Tiejun Chen
2015-07-13 13:12 ` Jan Beulich
2015-07-14 6:39 ` Chen, Tiejun
2015-07-14 9:27 ` Jan Beulich
2015-07-14 10:54 ` Chen, Tiejun
2015-07-14 11:50 ` Jan Beulich
2015-07-15 0:55 ` Chen, Tiejun
2015-07-15 4:27 ` Chen, Tiejun
2015-07-15 8:34 ` Jan Beulich
2015-07-15 8:59 ` Chen, Tiejun
2015-07-15 9:10 ` Chen, Tiejun
2015-07-15 9:27 ` Jan Beulich
2015-07-15 10:34 ` Chen, Tiejun
2015-07-15 11:25 ` Jan Beulich
2015-07-15 11:34 ` Chen, Tiejun
2015-07-15 13:56 ` George Dunlap
2015-07-15 16:14 ` George Dunlap
2015-07-16 2:05 ` Chen, Tiejun
2015-07-16 9:40 ` George Dunlap
2015-07-16 10:01 ` Chen, Tiejun
2015-07-15 11:05 ` George Dunlap
2015-07-15 11:20 ` Chen, Tiejun
2015-07-15 12:43 ` George Dunlap
2015-07-15 13:23 ` Chen, Tiejun
2015-07-15 11:24 ` Jan Beulich
2015-07-15 11:38 ` George Dunlap
2015-07-15 11:27 ` Jan Beulich
2015-07-15 11:40 ` Chen, Tiejun
2015-07-15 8:32 ` Jan Beulich
2015-07-15 9:04 ` Chen, Tiejun
2015-07-15 12:57 ` Wei Liu
2015-07-15 13:40 ` George Dunlap
2015-07-15 14:00 ` Jan Beulich
2015-07-15 15:19 ` George Dunlap
2015-07-09 5:33 ` [v7][PATCH 07/16] hvmloader/e820: construct guest e820 table Tiejun Chen
2015-07-13 13:35 ` Jan Beulich
2015-07-14 5:22 ` Chen, Tiejun
2015-07-14 9:32 ` Jan Beulich
2015-07-14 10:22 ` Chen, Tiejun
2015-07-14 10:48 ` Jan Beulich
2015-07-15 16:00 ` George Dunlap
2015-07-16 1:58 ` Chen, Tiejun
2015-07-16 9:41 ` George Dunlap
2015-07-09 5:33 ` [v7][PATCH 08/16] tools/libxc: Expose new hypercall xc_reserved_device_memory_map Tiejun Chen
2015-07-09 5:34 ` [v7][PATCH 09/16] tools: extend xc_assign_device() to support rdm reservation policy Tiejun Chen
2015-07-09 5:34 ` [v7][PATCH 10/16] tools: introduce some new parameters to set rdm policy Tiejun Chen
2015-07-09 9:20 ` Wei Liu
2015-07-09 9:44 ` Chen, Tiejun
2015-07-09 10:37 ` Ian Jackson
2015-07-09 10:53 ` Chen, Tiejun
2015-07-09 18:02 ` Ian Jackson
2015-07-10 0:46 ` Chen, Tiejun
2015-07-09 5:34 ` [v7][PATCH 11/16] tools/libxl: detect and avoid conflicts with RDM Tiejun Chen
2015-07-09 9:11 ` Wei Liu
2015-07-09 9:41 ` Chen, Tiejun
2015-07-09 18:14 ` Ian Jackson
2015-07-10 3:19 ` Chen, Tiejun
2015-07-10 10:14 ` Ian Jackson
2015-07-13 9:19 ` Chen, Tiejun
2015-07-09 5:34 ` [v7][PATCH 12/16] tools: introduce a new parameter to set a predefined rdm boundary Tiejun Chen
2015-07-09 18:14 ` Ian Jackson
2015-07-09 5:34 ` [v7][PATCH 13/16] libxl: construct e820 map with RDM information for HVM guest Tiejun Chen
2015-07-09 18:17 ` Ian Jackson
2015-07-10 5:40 ` Chen, Tiejun
2015-07-10 9:18 ` Ian Campbell
2015-07-13 9:47 ` Chen, Tiejun
2015-07-13 10:15 ` Ian Campbell
2015-07-14 5:44 ` Chen, Tiejun
2015-07-14 7:42 ` Ian Campbell
2015-07-14 8:03 ` Chen, Tiejun
2015-07-10 10:15 ` Ian Jackson
2015-07-09 5:34 ` [v7][PATCH 14/16] xen/vtd: enable USB device assignment Tiejun Chen
2015-07-09 5:34 ` [v7][PATCH 15/16] xen/vtd: prevent from assign the device with shared rmrr Tiejun Chen
2015-07-13 13:41 ` Jan Beulich
2015-07-14 1:42 ` Chen, Tiejun
2015-07-14 9:19 ` Jan Beulich
2015-07-09 5:34 ` [v7][PATCH 16/16] tools: parse to enable new rdm policy parameters Tiejun Chen
2015-07-09 18:23 ` Ian Jackson
2015-07-10 6:05 ` Chen, Tiejun
2015-07-10 10:23 ` Ian Jackson
2015-07-13 9:31 ` Chen, Tiejun
2015-07-13 9:40 ` Ian Campbell
2015-07-13 9:55 ` Chen, Tiejun
2015-07-13 10:17 ` Ian Campbell
2015-07-13 17:08 ` Ian Jackson
2015-07-14 1:29 ` Chen, Tiejun
2015-07-10 14:50 ` [v7][PATCH 00/16] Fix RMRR George Dunlap
2015-07-10 14:56 ` Jan Beulich
2015-07-16 7:55 ` Jan Beulich
2015-07-16 8:03 ` Chen, Tiejun
2015-07-16 8:08 ` Jan Beulich
2015-07-16 8:13 ` Chen, Tiejun
2015-07-16 8:26 ` Jan Beulich
2015-07-16 9:27 ` George Dunlap
2015-07-16 9:44 ` Jan Beulich
2015-07-16 9:59 ` George Dunlap
2015-07-16 8:30 ` Ian Campbell
2015-07-16 8:46 ` Wei Liu
2015-07-16 9:45 ` Lars Kurth
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