105 lines
3.7 KiB
Diff
105 lines
3.7 KiB
Diff
From c358fd4c224a9c3f64b4a8fff34cc6b1dc201fa0 Mon Sep 17 00:00:00 2001
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From: Bandan Das <bsd@redhat.com>
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Date: Tue, 3 Dec 2013 20:05:13 +0100
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Subject: vfio: cap number of devices that can be assigned
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RH-Author: Bandan Das <bsd@redhat.com>
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Message-id: <1386101113-31560-3-git-send-email-bsd@redhat.com>
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Patchwork-id: 55984
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O-Subject: [PATCH RHEL7 qemu-kvm v2 2/2] vfio: cap number of devices that can be assigned
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Bugzilla: 678368
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RH-Acked-by: Alex Williamson <alex.williamson@redhat.com>
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RH-Acked-by: Marcelo Tosatti <mtosatti@redhat.com>
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RH-Acked-by: Michael S. Tsirkin <mst@redhat.com>
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Go through all groups to get count of total number of devices
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active to enforce limit
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Reasoning from Alex for the limit(32) - Assuming 3 slots per
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device, with 125 slots (number of memory slots for RHEL 7),
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we can support almost 40 devices and still have few slots left
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for other uses. Stepping down a bit, the number 32 arbitrarily
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matches the number of slots on a PCI bus and is also a nice power
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of two.
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Count of slots increased to 509 later so we could increase limit
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to 64 as some usecases require more than 32 devices.
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Signed-off-by: Bandan Das <bsd@redhat.com>
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---
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hw/vfio/pci.c | 29 ++++++++++++++++++++++++++++-
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hw/vfio/pci.h | 1 +
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2 files changed, 29 insertions(+), 1 deletion(-)
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diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
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index 67a183f17b..1e20f9fd59 100644
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--- a/hw/vfio/pci.c
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+++ b/hw/vfio/pci.c
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@@ -45,6 +45,9 @@
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#define TYPE_VFIO_PCI_NOHOTPLUG "vfio-pci-nohotplug"
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+/* RHEL only: Set once for the first assigned dev */
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+static uint16_t device_limit;
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+
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static void vfio_disable_interrupts(VFIOPCIDevice *vdev);
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static void vfio_mmap_set_enabled(VFIOPCIDevice *vdev, bool enabled);
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@@ -2810,9 +2813,30 @@ static void vfio_realize(PCIDevice *pdev, Error **errp)
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ssize_t len;
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struct stat st;
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int groupid;
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- int i, ret;
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+ int ret, i = 0;
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bool is_mdev;
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+ if (device_limit && device_limit != vdev->assigned_device_limit) {
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+ error_setg(errp, "Assigned device limit has been redefined. "
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+ "Old:%d, New:%d",
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+ device_limit, vdev->assigned_device_limit);
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+ return;
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+ } else {
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+ device_limit = vdev->assigned_device_limit;
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+ }
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+
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+ QLIST_FOREACH(group, &vfio_group_list, next) {
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+ QLIST_FOREACH(vbasedev_iter, &group->device_list, next) {
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+ i++;
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+ }
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+ }
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+
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+ if (i >= vdev->assigned_device_limit) {
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+ error_setg(errp, "Maximum supported vfio devices (%d) "
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+ "already attached", vdev->assigned_device_limit);
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+ return;
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+ }
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+
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if (!vdev->vbasedev.sysfsdev) {
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if (!(~vdev->host.domain || ~vdev->host.bus ||
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~vdev->host.slot || ~vdev->host.function)) {
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@@ -3249,6 +3273,9 @@ static Property vfio_pci_dev_properties[] = {
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DEFINE_PROP_BOOL("x-no-kvm-msix", VFIOPCIDevice, no_kvm_msix, false),
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DEFINE_PROP_BOOL("x-no-geforce-quirks", VFIOPCIDevice,
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no_geforce_quirks, false),
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+ /* RHEL only */
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+ DEFINE_PROP_UINT16("x-assigned-device-limit", VFIOPCIDevice,
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+ assigned_device_limit, 64),
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DEFINE_PROP_BOOL("x-no-kvm-ioeventfd", VFIOPCIDevice, no_kvm_ioeventfd,
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false),
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DEFINE_PROP_BOOL("x-no-vfio-ioeventfd", VFIOPCIDevice, no_vfio_ioeventfd,
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diff --git a/hw/vfio/pci.h b/hw/vfio/pci.h
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index 64777516d1..e0fe6ca97e 100644
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--- a/hw/vfio/pci.h
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+++ b/hw/vfio/pci.h
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@@ -139,6 +139,7 @@ struct VFIOPCIDevice {
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EventNotifier err_notifier;
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EventNotifier req_notifier;
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int (*resetfn)(struct VFIOPCIDevice *);
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+ uint16_t assigned_device_limit;
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uint32_t vendor_id;
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uint32_t device_id;
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uint32_t sub_vendor_id;
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--
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2.31.1
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