From: Nicolin Chen <nicolinc@nvidia.com>
To: Jacob Pan <jacob.pan@linux.microsoft.com>
Cc: <will@kernel.org>, <robin.murphy@arm.com>, <jgg@nvidia.com>,
<kevin.tian@intel.com>, <tglx@linutronix.de>, <maz@kernel.org>,
<alex.williamson@redhat.com>, <joro@8bytes.org>,
<shuah@kernel.org>, <reinette.chatre@intel.com>,
<eric.auger@redhat.com>, <yebin10@huawei.com>,
<apatel@ventanamicro.com>, <shivamurthy.shastri@linutronix.de>,
<bhelgaas@google.com>, <anna-maria@linutronix.de>,
<yury.norov@gmail.com>, <nipun.gupta@amd.com>,
<iommu@lists.linux.dev>, <linux-kernel@vger.kernel.org>,
<linux-arm-kernel@lists.infradead.org>, <kvm@vger.kernel.org>,
<linux-kselftest@vger.kernel.org>, <patches@lists.linux.dev>,
<jean-philippe@linaro.org>, <mdf@kernel.org>,
<mshavit@google.com>, <shameerali.kolothum.thodi@huawei.com>,
<smostafa@google.com>, <ddutile@redhat.com>
Subject: Re: [PATCH RFCv2 00/13] iommu: Add MSI mapping support with nested SMMU
Date: Wed, 5 Feb 2025 14:56:15 -0800 [thread overview]
Message-ID: <Z6Psj2+ingBos0Bn@Asurada-Nvidia> (raw)
In-Reply-To: <20250205144904.39285de4@DESKTOP-0403QTC.>
On Wed, Feb 05, 2025 at 02:49:04PM -0800, Jacob Pan wrote:
> > There have been two approaches to solve this problem:
> > 1. Create an identity mapping in the stage-1. VMM could insert a few
> > RMRs (Reserved Memory Regions) in guest's IORT. Then the guest kernel
> > would fetch these RMR entries from the IORT and create an
> > IOMMU_RESV_DIRECT region per iommu group for a direct mapping.
> > Eventually, the mappings would look like: IOVA (0x8000000) === IPA
> > (0x8000000) ===> 0x20200000 This requires an IOMMUFD ioctl for kernel
> > and VMM to agree on the IPA.
>
> Should this RMR be in a separate range than MSI_IOVA_BASE? The guest
> will have MSI_IOVA_BASE in a reserved region already, no?
> e.g. # cat
> /sys/bus/pci/devices/0015\:01\:00.0/iommu_group/reserved_regions
> 0x0000000008000000 0x00000000080fffff msi
No. In Patch-9, the driver-defined MSI_IOVA_BASE will be ignored if
userspace has assigned IOMMU_OPTION_SW_MSI_START/SIZE, even if they
might have the same values as the MSI_IOVA_BASE window.
The idea of MSI_IOVA_BASE in this series is a kernel default that'd
be only effective when user space doesn't care to set anything.
Thanks
Nicolin
next prev parent reply other threads:[~2025-02-05 22:58 UTC|newest]
Thread overview: 64+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-01-11 3:32 [PATCH RFCv2 00/13] iommu: Add MSI mapping support with nested SMMU Nicolin Chen
2025-01-11 3:32 ` [PATCH RFCv2 01/13] genirq/msi: Store the IOMMU IOVA directly in msi_desc instead of iommu_cookie Nicolin Chen
2025-01-23 17:10 ` Eric Auger
2025-01-23 18:48 ` Jason Gunthorpe
2025-01-29 12:11 ` Eric Auger
2025-01-11 3:32 ` [PATCH RFCv2 02/13] genirq/msi: Rename iommu_dma_compose_msi_msg() to msi_msg_set_msi_addr() Nicolin Chen
2025-01-23 17:10 ` Eric Auger
2025-01-23 18:50 ` Jason Gunthorpe
2025-01-29 10:44 ` Eric Auger
2025-01-11 3:32 ` [PATCH RFCv2 03/13] iommu: Make iommu_dma_prepare_msi() into a generic operation Nicolin Chen
2025-01-23 17:10 ` Eric Auger
2025-01-23 18:16 ` Jason Gunthorpe
2025-01-29 12:29 ` Eric Auger
2025-01-11 3:32 ` [PATCH RFCv2 04/13] irqchip: Have CONFIG_IRQ_MSI_IOMMU be selected by the irqchips that need it Nicolin Chen
2025-01-11 3:32 ` [PATCH RFCv2 05/13] iommu: Turn fault_data to iommufd private pointer Nicolin Chen
2025-01-23 9:54 ` Tian, Kevin
2025-01-23 13:25 ` Jason Gunthorpe
2025-01-29 12:40 ` Eric Auger
2025-02-03 17:48 ` Nicolin Chen
2025-01-11 3:32 ` [PATCH RFCv2 06/13] iommufd: Make attach_handle generic Nicolin Chen
2025-01-18 8:23 ` Yi Liu
2025-01-18 20:32 ` Nicolin Chen
2025-01-19 10:40 ` Yi Liu
2025-01-20 5:54 ` Nicolin Chen
2025-01-24 13:31 ` Yi Liu
2025-01-20 14:20 ` Jason Gunthorpe
2025-01-29 13:14 ` Eric Auger
2025-02-03 18:08 ` Nicolin Chen
2025-01-11 3:32 ` [PATCH RFCv2 07/13] iommufd: Implement sw_msi support natively Nicolin Chen
2025-01-15 4:21 ` Yury Norov
2025-01-16 20:21 ` Jason Gunthorpe
2025-01-23 19:30 ` Jason Gunthorpe
2025-01-11 3:32 ` [PATCH RFCv2 08/13] iommu: Turn iova_cookie to dma-iommu private pointer Nicolin Chen
2025-01-13 16:40 ` Jason Gunthorpe
2025-01-11 3:32 ` [PATCH RFCv2 09/13] iommufd: Add IOMMU_OPTION_SW_MSI_START/SIZE ioctls Nicolin Chen
2025-01-23 10:07 ` Tian, Kevin
2025-02-03 18:36 ` Nicolin Chen
2025-01-29 13:44 ` Eric Auger
2025-01-29 14:58 ` Jason Gunthorpe
2025-01-29 17:23 ` Eric Auger
2025-01-29 17:39 ` Jason Gunthorpe
2025-01-29 17:49 ` Eric Auger
2025-01-29 20:15 ` Jason Gunthorpe
2025-02-07 4:26 ` Nicolin Chen
2025-02-07 14:30 ` Jason Gunthorpe
2025-02-07 15:28 ` Jason Gunthorpe
2025-02-07 18:59 ` Nicolin Chen
2025-02-09 18:09 ` Jason Gunthorpe
2025-01-11 3:32 ` [PATCH RFCv2 10/13] iommufd/selftes: Add coverage for IOMMU_OPTION_SW_MSI_START/SIZE Nicolin Chen
2025-01-11 3:32 ` [PATCH RFCv2 11/13] iommufd/device: Allow setting IOVAs for MSI(x) vectors Nicolin Chen
2025-01-11 3:32 ` [PATCH RFCv2 12/13] vfio-iommufd: Provide another layer of msi_iova helpers Nicolin Chen
2025-01-11 3:32 ` [PATCH RFCv2 13/13] vfio/pci: Allow preset MSI IOVAs via VFIO_IRQ_SET_ACTION_PREPARE Nicolin Chen
2025-01-23 9:06 ` [PATCH RFCv2 00/13] iommu: Add MSI mapping support with nested SMMU Shameerali Kolothum Thodi
2025-01-23 13:24 ` Jason Gunthorpe
2025-01-29 14:54 ` Eric Auger
2025-01-29 15:04 ` Jason Gunthorpe
2025-01-29 17:46 ` Eric Auger
2025-01-29 20:13 ` Jason Gunthorpe
2025-02-04 12:55 ` Eric Auger
2025-02-04 13:02 ` Jason Gunthorpe
2025-02-05 22:49 ` Jacob Pan
2025-02-05 22:56 ` Nicolin Chen [this message]
2025-02-07 14:34 ` Jason Gunthorpe
2025-02-07 14:42 ` Thomas Gleixner
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