Red Hat Bugzilla – Bug 1119206
RFE: Multiple virtio-rng devices support
Last modified: 2015-03-05 02:41:02 EST
+++ This bug was initially created as a clone of Bug #915335 +++ Both qemu-kvm and the kernel support now multiple virtio-rng devices. Libvirt's support was crippled to support just one device as the original intent was not to support multiple RNGs. This bug will track adding support for multiple RNGs in a domain. There was already an attempt to add this: http://www.redhat.com/archives/libvir-list/2013-February/msg01423.html Kernel commits adding the support: commit a17597d3b418ca5a394d14724ccfc295cb3186c8 Author: Sasha Levin <sasha.levin@oracle.com> Date: Fri May 16 11:42:43 2014 +0930 virtio-rng: fixes for device registration/unregistration There are several fixes in this patch (mostly because it's hard splitting them up): - Revert the name field in struct hwrng back to 'const'. Also, don't do an extra kmalloc for the name - just wasteful. - Deal with allocation failures properly. - Use IDA to allocate device number instead of brute forcing one. Signed-off-by: Sasha Levin <sasha.levin@oracle.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> commit e5d23a8cc38c555f9f3a40dcc5d14030105df9a8 Author: Sasha Levin <sasha.levin@oracle.com> Date: Fri May 16 11:41:57 2014 +0930 virtio-rng: fix boot with virtio-rng device Commit "virtio-rng: support multiple virtio-rng devices" has broken boot with a virtio-rng device because the 'init' callback of the virtio-rng device was left unitialized to garbage, and got called by the hwrng infrastructure, killing the guest on boot. Signed-off-by: Sasha Levin <sasha.levin@oracle.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Fixes: 08e53fbdb85c0f6f45c0f7c1ea3defc1752a95ce commit 08e53fbdb85c0f6f45c0f7c1ea3defc1752a95ce Author: Amos Kong <akong@redhat.com> Date: Wed May 14 10:33:46 2014 +0930 virtio-rng: support multiple virtio-rng devices Current hwrng core supports to register multiple hwrng devices, and there is only one device really works in the same time. QEMU alsu supports to have multiple virtio-rng backends. This patch changes virtio-rng driver to support multiple virtio-rng devices. ]# cat /sys/class/misc/hw_random/rng_available virtio_rng.0 virtio_rng.1 ]# cat /sys/class/misc/hw_random/rng_current virtio_rng.0 ]# echo -n virtio_rng.1 > /sys/class/misc/hw_random/rng_current ]# dd if=/dev/hwrng of=/dev/null Signed-off-by: Amos Kong <akong@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Libvirt added this feature in v1.2.6-261-g7214d5d: commit 7214d5da28c90fcdb62345190e34c76a345f9f70 Author: Peter Krempa <pkrempa@redhat.com> Date: Thu Jul 24 15:15:20 2014 +0200 test: qemu: Add tests for multiple virtio-rng devices commit bbddbefa2f8a8ef72287077d7d4b7190f3bf2609 Author: Peter Krempa <pkrempa@redhat.com> Date: Mon Feb 25 23:31:11 2013 +0100 virtio-rng: allow multiple RNG devices qemu supports adding multiple RNG devices. This patch allows libvirt to support this.
Verify this bug with libvirt-1.2.8-10.el7.x86_64 : 1.Start a guest with multiple virtio-rng devices # virsh list Id Name State ---------------------------------------------------- 42 r7 running # virsh dumpxml r7 <rng model='virtio'> <backend model='random'>/dev/random</backend> <address type='pci' domain='0x0000' bus='0x00' slot='0x09' function='0x0'/> </rng> <rng model='virtio'> <backend model='random'>/dev/random</backend> <address type='pci' domain='0x0000' bus='0x00' slot='0x0a' function='0x0'/> </rng> <rng model='virtio'> <backend model='egd' type='udp'> <source mode='connect' host='localhost' service='1234'/> </backend> <address type='pci' domain='0x0000' bus='0x00' slot='0x0b' function='0x0'/> </rng> </devices> 2.check qemu cmd line: # ps aux|grep qemu -object rng-random,id=rng0,filename=/dev/random -device virtio-rng-pci,rng=rng0,bus=pci.0,addr=0x9 -object rng-random,id=rng1,filename=/dev/random -device virtio-rng-pci,rng=rng1,bus=pci.0,addr=0xa -chardev udp,id=charrng2,host=localhost,port=1234,localaddr=,localport=0 -object rng-egd,chardev=charrng2,id=rng2 -device virtio-rng-pci,rng=rng2,bus=pci.0,addr=0xb 2.login guest to check if virtio_rng work well IN GUEST: # time cat /sys/devices/virtual/misc/hw_random/rng_current virtio_rng.0 real 0m39.333s user 0m0.002s sys 0m0.000s # time cat /sys/devices/virtual/misc/hw_random/rng_available virtio_rng.0 virtio_rng.1 virtio_rng.2 real 0m24.679s user 0m0.000s sys 0m0.002s # echo -n virtio_rng.1 > /sys/class/misc/hw_random/rng_current # dd if=/dev/hwrng of=/tmp/random ^C^C5+1 records in 5+0 records out 2560 bytes (2.6 kB) copied, 495.8 s, 0.0 kB/s It is very slow and this issue seems because bug 1008860.
Hi peter, I found this bug depends on bug 917953, but bug 917953 is a bug tracker of qemu-kvm, can i verify this bug now？ Thanks in advance for your answer.
(In reply to Luyao Huang from comment #4) > Hi peter, > > I found this bug depends on bug 917953, but bug 917953 is a bug tracker of > qemu-kvm, can i verify this bug now？ That bug dependency is probably wrong. As you were able to checked that it works then it's okay to set it to VERIFIED.
(In reply to Peter Krempa from comment #5) > (In reply to Luyao Huang from comment #4) > > Hi peter, > > > > I found this bug depends on bug 917953, but bug 917953 is a bug tracker of > > qemu-kvm, can i verify this bug now？ > > That bug dependency is probably wrong. As you were able to checked that it > works then it's okay to set it to VERIFIED. Thanks for your reply and verify this bug
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://rhn.redhat.com/errata/RHSA-2015-0323.html