From: Tianyu Lan <ltykernel@gmail.com>
To: Boris Ostrovsky <boris.ostrovsky@oracle.com>,
kys@microsoft.com, haiyangz@microsoft.com,
sthemmin@microsoft.com, wei.liu@kernel.org, decui@microsoft.com,
tglx@linutronix.de, mingo@redhat.com, bp@alien8.de,
x86@kernel.org, hpa@zytor.com, arnd@arndb.de,
dave.hansen@linux.intel.com, luto@kernel.org,
peterz@infradead.org, akpm@linux-foundation.org,
kirill.shutemov@linux.intel.com, rppt@kernel.org,
hannes@cmpxchg.org, cai@lca.pw, krish.sadhukhan@oracle.com,
saravanand@fb.com, Tianyu.Lan@microsoft.com,
konrad.wilk@oracle.com, hch@lst.de, m.szyprowski@samsung.com,
robin.murphy@arm.com, jgross@suse.com, sstabellini@kernel.org,
joro@8bytes.org, will@kernel.org, xen-devel@lists.xenproject.org,
davem@davemloft.net, kuba@kernel.org, jejb@linux.ibm.com,
martin.petersen@oracle.com
Cc: iommu@lists.linux-foundation.org, linux-arch@vger.kernel.org,
linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-scsi@vger.kernel.org, netdev@vger.kernel.org,
vkuznets@redhat.com, thomas.lendacky@amd.com,
brijesh.singh@amd.com, sunilmut@microsoft.com
Subject: Re: [RFC PATCH V3 09/11] HV/IOMMU: Enable swiotlb bounce buffer for Isolation VM
Date: Thu, 3 Jun 2021 23:37:06 +0800 [thread overview]
Message-ID: <1cdf4e6e-6499-e209-d499-7ab82992040b@gmail.com> (raw)
In-Reply-To: <d6714e8b-dcb6-798b-59a4-5bb68f789564@oracle.com>
On 6/3/2021 12:02 AM, Boris Ostrovsky wrote:
>
> On 6/2/21 11:01 AM, Tianyu Lan wrote:
>> Hi Boris:
>> Thanks for your review.
>>
>> On 6/2/2021 9:16 AM, Boris Ostrovsky wrote:
>>>
>>> On 5/30/21 11:06 AM, Tianyu Lan wrote:
>>>> @@ -91,6 +92,6 @@ int pci_xen_swiotlb_init_late(void)
>>>> EXPORT_SYMBOL_GPL(pci_xen_swiotlb_init_late);
>>>> IOMMU_INIT_FINISH(2,
>>>> - NULL,
>>>> + hyperv_swiotlb_detect,
>>>> pci_xen_swiotlb_init,
>>>> NULL);
>>>
>>>
>>> Could you explain this change?
>>
>> Hyper-V allocates its own swiotlb bounce buffer and the default
>> swiotlb buffer should not be allocated. swiotlb_init() in pci_swiotlb_init() is to allocate default swiotlb buffer.
>> To achieve this, put hyperv_swiotlb_detect() as the first entry in the iommu_table_entry list. The detect loop in the pci_iommu_alloc() will exit once hyperv_swiotlb_detect() is called in Hyper-V VM and other iommu_table_entry callback will not be called.
>
>
>
> Right. But pci_xen_swiotlb_detect() will only do something for Xen PV guests, and those guests don't run on hyperV. It's either xen_pv_domain() (i.e. hypervisor_is_type(X86_HYPER_XEN_PV)) or hypervisor_is_type(X86_HYPER_MS_HYPERV) but never both. So I don't think there needs to be a dependency between the two callbacks.
Yes, the dependency is between hyperv_swiotlb_detect() and
pci_swiotlb_detect_override()/pci_swiotlb_detect_4gb(). Now
pci_swiotlb_detect_override() and pci_swiotlb_detect_4gb() depends on
pci_xen_swiotlb_detect(). To keep dependency between
hyperv_swiotlb_detect() and pci_swiotlb_detect_override/4gb(), make
pci_xen_swiotlb_detect() depends on hyperv_swiotlb_detect() and just to
keep order in the IOMMU table. Current iommu_table_entry only has one
depend callback and this is why I put xen depends on hyperv detect function.
Thanks.
next prev parent reply other threads:[~2021-06-03 15:38 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-30 15:06 [RFC PATCH V3 00/11] x86/Hyper-V: Add Hyper-V Isolation VM support Tianyu Lan
2021-05-30 15:06 ` [RFC PATCH V3 01/11] x86/HV: Initialize GHCB page in Isolation VM Tianyu Lan
2021-06-07 6:41 ` Christoph Hellwig
2021-06-07 8:14 ` Tianyu Lan
2021-06-09 12:38 ` Joerg Roedel
2021-06-10 14:13 ` Tianyu Lan
2021-05-30 15:06 ` [RFC PATCH V3 02/11] x86/HV: Initialize shared memory boundary in the " Tianyu Lan
2021-05-30 15:06 ` [RFC PATCH V3 03/11] x86/Hyper-V: Add new hvcall guest address host visibility support Tianyu Lan
2021-05-30 18:25 ` Borislav Petkov
2021-05-31 4:08 ` Tianyu Lan
2021-06-10 9:47 ` Vitaly Kuznetsov
2021-06-10 14:18 ` Tianyu Lan
2021-05-30 15:06 ` [RFC PATCH V3 04/11] HV: Add Write/Read MSR registers via ghcb Tianyu Lan
2021-06-09 12:46 ` Joerg Roedel
2021-06-10 14:15 ` Tianyu Lan
2021-05-30 15:06 ` [RFC PATCH V3 05/11] HV: Add ghcb hvcall support for SNP VM Tianyu Lan
2021-06-09 12:49 ` Joerg Roedel
2021-05-30 15:06 ` [RFC PATCH V3 06/11] HV/Vmbus: Add SNP support for VMbus channel initiate message Tianyu Lan
2021-05-30 15:06 ` [RFC PATCH V3 07/11] HV/Vmbus: Initialize VMbus ring buffer for Isolation VM Tianyu Lan
2021-05-30 15:06 ` [RFC PATCH V3 08/11] swiotlb: Add bounce buffer remap address setting function Tianyu Lan
2021-06-07 6:43 ` Christoph Hellwig
2021-06-07 14:56 ` Tianyu Lan
2021-06-10 14:25 ` Tianyu Lan
2021-06-14 7:12 ` Christoph Hellwig
2021-06-14 13:29 ` Tom Lendacky
2021-06-14 13:37 ` Tianyu Lan
2021-06-14 13:42 ` Tianyu Lan
2021-06-14 13:49 ` Robin Murphy
2021-06-14 15:32 ` Christoph Hellwig
2021-06-15 15:24 ` Tianyu Lan
2021-07-12 9:40 ` Tianyu Lan
2021-05-30 15:06 ` [RFC PATCH V3 09/11] HV/IOMMU: Enable swiotlb bounce buffer for Isolation VM Tianyu Lan
2021-06-02 1:16 ` Boris Ostrovsky
2021-06-02 15:01 ` Tianyu Lan
2021-06-02 16:02 ` Boris Ostrovsky
2021-06-03 15:37 ` Tianyu Lan [this message]
2021-06-03 17:04 ` Boris Ostrovsky
2021-06-07 6:44 ` Christoph Hellwig
2021-05-30 15:06 ` [RFC PATCH V3 10/11] HV/Netvsc: Add Isolation VM support for netvsc driver Tianyu Lan
2021-06-07 6:50 ` Christoph Hellwig
2021-06-07 15:21 ` Tianyu Lan
2021-06-14 7:09 ` Christoph Hellwig
2021-06-14 14:04 ` Tianyu Lan
2021-06-14 15:33 ` Christoph Hellwig
2021-06-15 14:31 ` Tianyu Lan
2021-06-10 9:52 ` Vitaly Kuznetsov
2021-05-30 15:06 ` [RFC PATCH V3 11/11] HV/Storvsc: Add Isolation VM support for storvsc driver Tianyu Lan
2021-06-07 6:46 ` Christoph Hellwig
2021-06-07 14:59 ` Tianyu Lan
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