From: Michael Kelley <mikelley@microsoft.com> To: sthemmin@microsoft.com, kys@microsoft.com, haiyangz@microsoft.com, wei.liu@kernel.org, decui@microsoft.com, rafael@kernel.org, lenb@kernel.org, lorenzo.pieralisi@arm.com, robh@kernel.org, kw@linux.com, bhelgaas@google.com, hch@lst.de, m.szyprowski@samsung.com, robin.murphy@arm.com, linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-pci@vger.kernel.org, iommu@lists.linux-foundation.org Cc: mikelley@microsoft.com Subject: [PATCH v3 0/2] Fix coherence for VMbus and PCI pass-thru devices in Hyper-V VM Date: Thu, 24 Mar 2022 09:14:50 -0700 [thread overview] Message-ID: <1648138492-2191-1-git-send-email-mikelley@microsoft.com> (raw) Hyper-V VMs have VMbus synthetic devices and PCI pass-thru devices that are added dynamically via the VMbus protocol and are not represented in the ACPI DSDT. Only the top level VMbus node exists in the DSDT. As such, on ARM64 these devices don't pick up coherence information and default to not hardware coherent. This results in extra software coherence management overhead since the synthetic devices are always hardware coherent. PCI pass-thru devices are also hardware coherent in all current usage scenarios. Fix this by propagating coherence information from the top level VMbus node in the DSDT to all VMbus synthetic devices and PCI pass-thru devices. While smaller granularity of control would be better, basing on the VMbus node in the DSDT gives as escape path if a future scenario arises with devices that are not hardware coherent. Changes since v2: * Move coherence propagation for VMbus synthetic devices to a separate .dma_configure function instead of the .probe fucntion [Robin Murphy] Changes since v1: * Use device_get_dma_attr() instead of acpi_get_dma_attr(), eliminating the need to export acpi_get_dma_attr() [Robin Murphy] * Use arch_setup_dma_ops() to set device coherence [Robin Murphy] * Move handling of missing _CCA to vmbus_acpi_add() so it is only done once * Rework handling of PCI devices so existing code in pci_dma_configure() just works Michael Kelley (2): Drivers: hv: vmbus: Propagate VMbus coherence to each VMbus device PCI: hv: Propagate coherence from VMbus device to PCI device drivers/hv/hv_common.c | 11 +++++++++++ drivers/hv/vmbus_drv.c | 31 +++++++++++++++++++++++++++++++ drivers/pci/controller/pci-hyperv.c | 9 +++++++++ include/asm-generic/mshyperv.h | 1 + 4 files changed, 52 insertions(+) -- 1.8.3.1
WARNING: multiple messages have this Message-ID (diff)
From: Michael Kelley via iommu <iommu@lists.linux-foundation.org> To: sthemmin@microsoft.com, kys@microsoft.com, haiyangz@microsoft.com, wei.liu@kernel.org, decui@microsoft.com, rafael@kernel.org, lenb@kernel.org, lorenzo.pieralisi@arm.com, robh@kernel.org, kw@linux.com, bhelgaas@google.com, hch@lst.de, m.szyprowski@samsung.com, robin.murphy@arm.com, linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-pci@vger.kernel.org, iommu@lists.linux-foundation.org Cc: mikelley@microsoft.com Subject: [PATCH v3 0/2] Fix coherence for VMbus and PCI pass-thru devices in Hyper-V VM Date: Thu, 24 Mar 2022 09:14:50 -0700 [thread overview] Message-ID: <1648138492-2191-1-git-send-email-mikelley@microsoft.com> (raw) Hyper-V VMs have VMbus synthetic devices and PCI pass-thru devices that are added dynamically via the VMbus protocol and are not represented in the ACPI DSDT. Only the top level VMbus node exists in the DSDT. As such, on ARM64 these devices don't pick up coherence information and default to not hardware coherent. This results in extra software coherence management overhead since the synthetic devices are always hardware coherent. PCI pass-thru devices are also hardware coherent in all current usage scenarios. Fix this by propagating coherence information from the top level VMbus node in the DSDT to all VMbus synthetic devices and PCI pass-thru devices. While smaller granularity of control would be better, basing on the VMbus node in the DSDT gives as escape path if a future scenario arises with devices that are not hardware coherent. Changes since v2: * Move coherence propagation for VMbus synthetic devices to a separate .dma_configure function instead of the .probe fucntion [Robin Murphy] Changes since v1: * Use device_get_dma_attr() instead of acpi_get_dma_attr(), eliminating the need to export acpi_get_dma_attr() [Robin Murphy] * Use arch_setup_dma_ops() to set device coherence [Robin Murphy] * Move handling of missing _CCA to vmbus_acpi_add() so it is only done once * Rework handling of PCI devices so existing code in pci_dma_configure() just works Michael Kelley (2): Drivers: hv: vmbus: Propagate VMbus coherence to each VMbus device PCI: hv: Propagate coherence from VMbus device to PCI device drivers/hv/hv_common.c | 11 +++++++++++ drivers/hv/vmbus_drv.c | 31 +++++++++++++++++++++++++++++++ drivers/pci/controller/pci-hyperv.c | 9 +++++++++ include/asm-generic/mshyperv.h | 1 + 4 files changed, 52 insertions(+) -- 1.8.3.1 _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
next reply other threads:[~2022-03-24 16:15 UTC|newest] Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-03-24 16:14 Michael Kelley [this message] 2022-03-24 16:14 ` [PATCH v3 0/2] Fix coherence for VMbus and PCI pass-thru devices in Hyper-V VM Michael Kelley via iommu 2022-03-24 16:14 ` [PATCH v3 1/2] Drivers: hv: vmbus: Propagate VMbus coherence to each VMbus device Michael Kelley 2022-03-24 16:14 ` Michael Kelley via iommu 2022-03-24 16:14 ` [PATCH v3 2/2] PCI: hv: Propagate coherence from VMbus device to PCI device Michael Kelley 2022-03-24 16:14 ` Michael Kelley via iommu 2022-03-29 12:15 ` [PATCH v3 0/2] Fix coherence for VMbus and PCI pass-thru devices in Hyper-V VM Wei Liu 2022-03-29 12:15 ` Wei Liu
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