qemu-kvm/0013-vfio-cap-number-of-devices-that-can-be-assigned.patch
2018-12-13 10:55:49 -02:00

77 lines
2.4 KiB
Diff

From 0b8b44ec1fc3a0d17f13c07ac4c7351769a63300 Mon Sep 17 00:00:00 2001
From: Bandan Das <bsd@redhat.com>
Date: Tue, 3 Dec 2013 20:05:13 +0100
Subject: vfio: cap number of devices that can be assigned
RH-Author: Bandan Das <bsd@redhat.com>
Message-id: <1386101113-31560-3-git-send-email-bsd@redhat.com>
Patchwork-id: 55984
O-Subject: [PATCH RHEL7 qemu-kvm v2 2/2] vfio: cap number of devices that can be assigned
Bugzilla: 678368
RH-Acked-by: Alex Williamson <alex.williamson@redhat.com>
RH-Acked-by: Marcelo Tosatti <mtosatti@redhat.com>
RH-Acked-by: Michael S. Tsirkin <mst@redhat.com>
Go through all groups to get count of total number of devices
active to enforce limit
Reasoning from Alex for the limit(32) - Assuming 3 slots per
device, with 125 slots (number of memory slots for RHEL 7),
we can support almost 40 devices and still have few slots left
for other uses. Stepping down a bit, the number 32 arbitrarily
matches the number of slots on a PCI bus and is also a nice power
of two.
Signed-off-by: Bandan Das <bsd@redhat.com>
Rebase notes (2.8.0):
- removed return value for vfio_realize (commit 1a22aca)
Merged patches (2.9.0):
- 17eb774 vfio: Use error_setg when reporting max assigned device overshoot
(cherry picked from commit 9fa3c9fc6dfcde76d80db1aa601b2d577f72ceec)
(cherry picked from commit 3cb35556dc7d994f203d732fe952f95fcdb03c0a)
---
hw/vfio/pci.c | 15 ++++++++++++++-
1 file changed, 14 insertions(+), 1 deletion(-)
diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
index 6e0000c..d242c62 100644
--- a/hw/vfio/pci.c
+++ b/hw/vfio/pci.c
@@ -36,6 +36,7 @@
#include "qapi/error.h"
#define MSIX_CAP_LENGTH 12
+#define MAX_DEV_ASSIGN_CMDLINE 32
#define TYPE_VFIO_PCI "vfio-pci"
#define PCI_VFIO(obj) OBJECT_CHECK(VFIOPCIDevice, obj, TYPE_VFIO_PCI)
@@ -2811,9 +2812,21 @@ static void vfio_realize(PCIDevice *pdev, Error **errp)
ssize_t len;
struct stat st;
int groupid;
- int i, ret;
+ int ret, i = 0;
bool is_mdev;
+ QLIST_FOREACH(group, &vfio_group_list, next) {
+ QLIST_FOREACH(vbasedev_iter, &group->device_list, next) {
+ i++;
+ }
+ }
+
+ if (i >= MAX_DEV_ASSIGN_CMDLINE) {
+ error_setg(errp, "Maximum supported vfio devices (%d) "
+ "already attached", MAX_DEV_ASSIGN_CMDLINE);
+ return;
+ }
+
if (!vdev->vbasedev.sysfsdev) {
if (!(~vdev->host.domain || ~vdev->host.bus ||
~vdev->host.slot || ~vdev->host.function)) {
--
1.8.3.1