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[Qemu-devel] [PULL 11/11] vfio/pci: Add option to disable GeForce quirks
From: |
Alex Williamson |
Subject: |
[Qemu-devel] [PULL 11/11] vfio/pci: Add option to disable GeForce quirks |
Date: |
Tue, 06 Feb 2018 11:44:08 -0700 |
User-agent: |
StGit/0.18-102-gdf9f |
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 <address@hidden>
---
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);
- [Qemu-devel] [PULL 01/11] memory/iommu: Add get_attr(), (continued)
- [Qemu-devel] [PULL 01/11] memory/iommu: Add get_attr(), Alex Williamson, 2018/02/06
- [Qemu-devel] [PULL 02/11] vfio/spapr: Use iommu memory region's get_attr(), Alex Williamson, 2018/02/06
- [Qemu-devel] [PULL 03/11] spapr/iommu: Enable in-kernel TCE acceleration via VFIO KVM device, Alex Williamson, 2018/02/06
- [Qemu-devel] [PULL 04/11] vfio/pci: Fixup VFIOMSIXInfo comment, Alex Williamson, 2018/02/06
- [Qemu-devel] [PULL 05/11] vfio/pci: Add base BAR MemoryRegion, Alex Williamson, 2018/02/06
- [Qemu-devel] [PULL 06/11] vfio/pci: Emulate BARs, Alex Williamson, 2018/02/06
- [Qemu-devel] [PULL 07/11] qapi: Create DEFINE_PROP_OFF_AUTO_PCIBAR, Alex Williamson, 2018/02/06
- [Qemu-devel] [PULL 08/11] vfio/pci: Allow relocating MSI-X MMIO, Alex Williamson, 2018/02/06
- [Qemu-devel] [PULL 09/11] hw/vfio/platform: Init the interrupt mutex, Alex Williamson, 2018/02/06
- [Qemu-devel] [PULL 10/11] vfio/common: Remove redundant copy of local variable, Alex Williamson, 2018/02/06
- [Qemu-devel] [PULL 11/11] vfio/pci: Add option to disable GeForce quirks,
Alex Williamson <=
- Re: [Qemu-devel] [PULL 00/11] VFIO updates 2018-02-06, Peter Maydell, 2018/02/07