From: Jason Wang <jasowang@redhat.com>
To: Zhenzhong Duan <zhenzhong.duan@intel.com>
Cc: qemu-devel@nongnu.org, alex@shazbot.org, clg@redhat.com,
eric.auger@redhat.com, mst@redhat.com, peterx@redhat.com,
ddutile@redhat.com, jgg@nvidia.com, nicolinc@nvidia.com,
skolothumtho@nvidia.com, joao.m.martins@oracle.com,
clement.mathieu--drif@eviden.com, kevin.tian@intel.com,
yi.l.liu@intel.com, chao.p.peng@intel.com
Subject: Re: [PATCH v8 02/23] intel_iommu: Delete RPS capability related supporting code
Date: Thu, 11 Dec 2025 16:22:54 +0800 [thread overview]
Message-ID: <CACGkMEtK_KiT+PCvxi2NUQ-gX0ekV3RtZ6E5T7oZSeiOqkSSkw@mail.gmail.com> (raw)
In-Reply-To: <20251117093729.1121324-3-zhenzhong.duan@intel.com>
On Mon, Nov 17, 2025 at 5:38 PM Zhenzhong Duan <zhenzhong.duan@intel.com> wrote:
>
> RID-PASID Support(RPS) is not set in vIOMMU ECAP register, the supporting
> code is there but never takes effect.
>
> Meanwhile, according to VTD spec section 3.4.3:
> "Implementations not supporting RID_PASID capability (ECAP_REG.RPS is 0b),
> use a PASID value of 0 to perform address translation for requests without
> PASID."
>
> We should delete the supporting code which fetches RID_PASID field from
> scalable context entry and use 0 as RID_PASID directly, because RID_PASID
> field is ignored if no RPS support according to spec.
>
> This simplifies the code and doesn't bring any penalty.
>
> Suggested-by: Yi Liu <yi.l.liu@intel.com>
> Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
> ---
Is the feature deprecated in the spec? If not, it should be still
better to enable it.
Thanks
next prev parent reply other threads:[~2025-12-11 8:23 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-11-17 9:37 [PATCH v8 00/23] intel_iommu: Enable first stage translation for passthrough device Zhenzhong Duan
2025-11-17 9:37 ` [PATCH v8 01/23] intel_iommu: Rename vtd_ce_get_rid2pasid_entry to vtd_ce_get_pasid_entry Zhenzhong Duan
2025-11-17 9:37 ` [PATCH v8 02/23] intel_iommu: Delete RPS capability related supporting code Zhenzhong Duan
2025-12-10 10:57 ` Eric Auger
2025-12-11 8:22 ` Jason Wang [this message]
2025-12-11 11:04 ` Yi Liu
2025-11-17 9:37 ` [PATCH v8 03/23] intel_iommu: Update terminology to match VTD spec Zhenzhong Duan
2025-11-17 9:37 ` [PATCH v8 04/23] hw/pci: Export pci_device_get_iommu_bus_devfn() and return bool Zhenzhong Duan
2025-11-17 9:37 ` [PATCH v8 05/23] hw/pci: Introduce pci_device_get_viommu_flags() Zhenzhong Duan
2025-11-17 9:37 ` [PATCH v8 06/23] intel_iommu: Implement get_viommu_flags() callback Zhenzhong Duan
2025-11-17 9:37 ` [PATCH v8 07/23] intel_iommu: Introduce a new structure VTDHostIOMMUDevice Zhenzhong Duan
2025-11-17 9:37 ` [PATCH v8 08/23] vfio/iommufd: Force creating nesting parent HWPT Zhenzhong Duan
2025-11-17 9:37 ` [PATCH v8 09/23] intel_iommu_accel: Check for compatibility with IOMMUFD backed device when x-flts=on Zhenzhong Duan
2025-12-10 13:59 ` Eric Auger
2025-12-11 6:49 ` Duan, Zhenzhong
2025-12-11 7:09 ` Eric Auger
2025-12-12 2:29 ` Duan, Zhenzhong
2025-11-17 9:37 ` [PATCH v8 10/23] intel_iommu_accel: Fail passthrough device under PCI bridge if x-flts=on Zhenzhong Duan
2025-12-10 14:01 ` Eric Auger
2025-11-17 9:37 ` [PATCH v8 11/23] intel_iommu_accel: Stick to system MR for IOMMUFD backed host device when x-flts=on Zhenzhong Duan
2025-12-10 14:02 ` Eric Auger
2025-11-17 9:37 ` [PATCH v8 12/23] intel_iommu: Add some macros and inline functions Zhenzhong Duan
2025-11-17 9:37 ` [PATCH v8 13/23] intel_iommu_accel: Bind/unbind guest page table to host Zhenzhong Duan
2025-12-10 17:42 ` Eric Auger
2025-12-11 7:52 ` Duan, Zhenzhong
2025-12-12 2:12 ` Duan, Zhenzhong
2025-12-12 3:02 ` Nicolin Chen
2025-11-17 9:37 ` [PATCH v8 14/23] intel_iommu_accel: Propagate PASID-based iotlb invalidation " Zhenzhong Duan
2025-12-10 17:49 ` Eric Auger
2025-11-17 9:37 ` [PATCH v8 15/23] intel_iommu: Replay all pasid bindings when either SRTP or TE bit is changed Zhenzhong Duan
2025-11-17 9:37 ` [PATCH v8 16/23] intel_iommu: Replay pasid bindings after context cache invalidation Zhenzhong Duan
2025-11-17 9:37 ` [PATCH v8 17/23] vfio/listener: Bypass readonly region for dirty tracking Zhenzhong Duan
2025-11-28 2:08 ` Duan, Zhenzhong
2025-11-28 4:27 ` Yi Liu
2025-11-28 5:47 ` Duan, Zhenzhong
2025-11-28 12:58 ` Cédric Le Goater
2025-12-01 3:21 ` Duan, Zhenzhong
2025-11-17 9:37 ` [PATCH v8 18/23] intel_iommu: Add migration support with x-flts=on Zhenzhong Duan
2025-11-17 9:37 ` [PATCH v8 19/23] hw/pci: Introduce pci_device_get_host_iommu_quirks() Zhenzhong Duan
2025-11-17 9:37 ` [PATCH v8 20/23] intel_iommu_accel: Implement get_host_iommu_quirks() callback Zhenzhong Duan
2025-11-17 9:37 ` [PATCH v8 21/23] Workaround for ERRATA_772415_SPR17 Zhenzhong Duan
2025-12-10 17:52 ` Eric Auger
2025-11-17 9:37 ` [PATCH v8 22/23] intel_iommu: Enable host device when x-flts=on in scalable mode Zhenzhong Duan
2025-11-17 9:37 ` [PATCH v8 23/23] docs/devel: Add IOMMUFD nesting documentation Zhenzhong Duan
2025-12-09 9:50 ` [PATCH v8 00/23] intel_iommu: Enable first stage translation for passthrough device Duan, Zhenzhong
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