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From 4110ee428550f672ee1a1a73a634d5392bf9c55f Mon Sep 17 00:00:00 2001
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Message-Id: <4110ee428550f672ee1a1a73a634d5392bf9c55f.1387382496.git.minovotn@redhat.com>
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In-Reply-To: <c5386144fbf09f628148101bc674e2421cdd16e3.1387382496.git.minovotn@redhat.com>
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References: <c5386144fbf09f628148101bc674e2421cdd16e3.1387382496.git.minovotn@redhat.com>
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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: [PATCH 44/46] 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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Signed-off-by: Bandan Das <bsd@redhat.com>
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---
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hw/misc/vfio.c | 15 ++++++++++++++-
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1 file changed, 14 insertions(+), 1 deletion(-)
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Signed-off-by: Michal Novotny <minovotn@redhat.com>
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---
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hw/misc/vfio.c | 15 ++++++++++++++-
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1 file changed, 14 insertions(+), 1 deletion(-)
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diff --git a/hw/misc/vfio.c b/hw/misc/vfio.c
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index 250f96f..bd30130 100644
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--- a/hw/misc/vfio.c
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+++ b/hw/misc/vfio.c
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@@ -201,6 +201,7 @@ typedef struct VFIOGroup {
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} VFIOGroup;
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#define MSIX_CAP_LENGTH 12
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+#define MAX_DEV_ASSIGN_CMDLINE 32
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static QLIST_HEAD(, VFIOContainer)
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container_list = QLIST_HEAD_INITIALIZER(container_list);
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@@ -3557,7 +3558,19 @@ static int vfio_initfn(PCIDevice *pdev)
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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 ret;
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+ int ret, i = 0;
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+
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+ QLIST_FOREACH(group, &group_list, next) {
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+ QLIST_FOREACH(pvdev, &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 >= MAX_DEV_ASSIGN_CMDLINE) {
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+ error_report("vfio: Maximum supported vfio devices (%d) "
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+ "already attached\n", MAX_DEV_ASSIGN_CMDLINE);
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+ return -1;
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+ }
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/* Check that the host device exists */
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snprintf(path, sizeof(path),
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--
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1.7.11.7
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