From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:34900) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ej8E6-0004pm-Ee for qemu-devel@nongnu.org; Tue, 06 Feb 2018 13:44:22 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ej8E2-0004dq-HY for qemu-devel@nongnu.org; Tue, 06 Feb 2018 13:44:18 -0500 Received: from mx1.redhat.com ([209.132.183.28]:41154) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1ej8E2-0004cp-7a for qemu-devel@nongnu.org; Tue, 06 Feb 2018 13:44:14 -0500 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 76B07C058EC2 for ; Tue, 6 Feb 2018 18:44:13 +0000 (UTC) From: Alex Williamson Date: Tue, 06 Feb 2018 11:44:08 -0700 Message-ID: <20180206184408.14644.31739.stgit@gimli.home> In-Reply-To: <20180206184101.14644.84734.stgit@gimli.home> References: <20180206184101.14644.84734.stgit@gimli.home> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Subject: [Qemu-devel] [PULL 11/11] vfio/pci: Add option to disable GeForce quirks List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org These quirks are necessary for GeForce, but not for Quadro/GRID/Tesla assignment. Leaving them enabled is fully functional and provides the most compatibility, but due to the unique NVIDIA MSI ACK behavior[1], it also introduces latency in re-triggering the MSI interrupt. This overhead is typically negligible, but has been shown to adversely affect some (very) high interrupt rate applications. This adds the vfio-pci device option "x-no-geforce-quirks=" which can be set to "on" to disable this additional overhead. A follow-on optimization for GeForce might be to make use of an ioeventfd to allow KVM to trigger an irqfd in the kernel vfio-pci driver, avoiding the bounce through userspace to handle this device write. [1] Background: the NVIDIA driver has been observed to issue a write to the MMIO mirror of PCI config space in BAR0 in order to allow the MSI interrupt for the device to retrigger. Older reports indicated a write of 0xff to the (read-only) MSI capability ID register, while more recently a write of 0x0 is observed at config space offset 0x704, non-architected, extended config space of the device (BAR0 offset 0x88704). Virtualization of this range is only required for GeForce. Signed-off-by: Alex Williamson --- hw/vfio/pci-quirks.c | 9 ++++++--- hw/vfio/pci.c | 2 ++ hw/vfio/pci.h | 1 + 3 files changed, 9 insertions(+), 3 deletions(-) diff --git a/hw/vfio/pci-quirks.c b/hw/vfio/pci-quirks.c index 60ad5fb91a83..e5779a7ad35b 100644 --- a/hw/vfio/pci-quirks.c +++ b/hw/vfio/pci-quirks.c @@ -542,7 +542,8 @@ static void vfio_vga_probe_nvidia_3d0_quirk(VFIOPCIDevice *vdev) VFIOQuirk *quirk; VFIONvidia3d0Quirk *data; - if (!vfio_pci_is(vdev, PCI_VENDOR_ID_NVIDIA, PCI_ANY_ID) || + if (vdev->no_geforce_quirks || + !vfio_pci_is(vdev, PCI_VENDOR_ID_NVIDIA, PCI_ANY_ID) || !vdev->bars[1].region.size) { return; } @@ -660,7 +661,8 @@ static void vfio_probe_nvidia_bar5_quirk(VFIOPCIDevice *vdev, int nr) VFIONvidiaBAR5Quirk *bar5; VFIOConfigWindowQuirk *window; - if (!vfio_pci_is(vdev, PCI_VENDOR_ID_NVIDIA, PCI_ANY_ID) || + if (vdev->no_geforce_quirks || + !vfio_pci_is(vdev, PCI_VENDOR_ID_NVIDIA, PCI_ANY_ID) || !vdev->vga || nr != 5 || !vdev->bars[5].ioport) { return; } @@ -754,7 +756,8 @@ static void vfio_probe_nvidia_bar0_quirk(VFIOPCIDevice *vdev, int nr) VFIOQuirk *quirk; VFIOConfigMirrorQuirk *mirror; - if (!vfio_pci_is(vdev, PCI_VENDOR_ID_NVIDIA, PCI_ANY_ID) || + if (vdev->no_geforce_quirks || + !vfio_pci_is(vdev, PCI_VENDOR_ID_NVIDIA, PCI_ANY_ID) || !vfio_is_vga(vdev) || nr != 0) { return; } diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c index cab2aecb8094..879510c046cd 100644 --- a/hw/vfio/pci.c +++ b/hw/vfio/pci.c @@ -3130,6 +3130,8 @@ static Property vfio_pci_dev_properties[] = { DEFINE_PROP_BOOL("x-no-kvm-intx", VFIOPCIDevice, no_kvm_intx, false), DEFINE_PROP_BOOL("x-no-kvm-msi", VFIOPCIDevice, no_kvm_msi, false), DEFINE_PROP_BOOL("x-no-kvm-msix", VFIOPCIDevice, no_kvm_msix, false), + DEFINE_PROP_BOOL("x-no-geforce-quirks", VFIOPCIDevice, + no_geforce_quirks, false), DEFINE_PROP_UINT32("x-pci-vendor-id", VFIOPCIDevice, vendor_id, PCI_ANY_ID), DEFINE_PROP_UINT32("x-pci-device-id", VFIOPCIDevice, device_id, PCI_ANY_ID), DEFINE_PROP_UINT32("x-pci-sub-vendor-id", VFIOPCIDevice, diff --git a/hw/vfio/pci.h b/hw/vfio/pci.h index 588381f201b4..f4aa13e021fa 100644 --- a/hw/vfio/pci.h +++ b/hw/vfio/pci.h @@ -146,6 +146,7 @@ typedef struct VFIOPCIDevice { bool no_kvm_intx; bool no_kvm_msi; bool no_kvm_msix; + bool no_geforce_quirks; } VFIOPCIDevice; uint32_t vfio_pci_read_config(PCIDevice *pdev, uint32_t addr, int len);