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v2: - this now separates both the patches; the virtio-rng fix is self-contained - re-work hwrng core to fetch randomness at device init time if ->init() is registered by the device, instead of not calling it at all. - virtio-rng: introduce a probe_done bool to ensure we don't ask host for data before successful probe Hi, When booting a recent kernel under KVM with the virtio-rng

v2: - this now separates both the patches; the virtio-rng fix is self-contained - re-work hwrng core to fetch randomness at device init time if ->init() is registered by the device, instead of not calling it at all. - virtio-rng: introduce a probe_done bool to ensure we don't ask host for data before successful probe Hi, When booting a recent kernel under KVM with the virtio-rng

Hi, When booting a recent kernel under KVM with the virtio-rng device enabled, the boot process was stalling. Bisect pointed to a commit made during the 3.15 window to fetch randomness from newly-registered devices in the hwrng core. The details are in the patches. I considered a couple of approaches, but basing on the init() function being registered, as is done in patch 1 here, seems like

Hi, When booting a recent kernel under KVM with the virtio-rng device enabled, the boot process was stalling. Bisect pointed to a commit made during the 3.15 window to fetch randomness from newly-registered devices in the hwrng core. The details are in the patches. I considered a couple of approaches, but basing on the init() function being registered, as is done in patch 1 here, seems like

On Wed, Jul 02, 2014 at 03:58:15PM +0530, Amit Shah wrote: > Commit d9e7972619334 "hwrng: add randomness to system from rng sources" > added a call to rng_get_data() from the hwrng_register() function. > However, some rng devices need initialization before data can be read > from them. > > Also, the virtio-rng device does not behave properly when this call is > made

On Wed, Jul 02, 2014 at 03:58:15PM +0530, Amit Shah wrote: > Commit d9e7972619334 "hwrng: add randomness to system from rng sources" > added a call to rng_get_data() from the hwrng_register() function. > However, some rng devices need initialization before data can be read > from them. > > Also, the virtio-rng device does not behave properly when this call is > made

On Wed, Jul 02, 2014 at 06:56:35PM +0530, Amit Shah wrote: > Hi Jason, > > On (Wed) 02 Jul 2014 [13:00:19], Jason Cooper wrote: > > Commit d9e7972619334 "hwrng: add randomness to system from rng sources" > > added a call to rng_get_data() from the hwrng_register() function. > > However, some rng devices need initialization before data can be read > >

On Wed, Jul 02, 2014 at 06:56:35PM +0530, Amit Shah wrote: > Hi Jason, > > On (Wed) 02 Jul 2014 [13:00:19], Jason Cooper wrote: > > Commit d9e7972619334 "hwrng: add randomness to system from rng sources" > > added a call to rng_get_data() from the hwrng_register() function. > > However, some rng devices need initialization before data can be read > >

Hi Gunter, I think this problem started happening when I upgraded from Debian Wheezy to Debian Jessie. If nothing looks amiss in my code, it probably is a sound driver problem. But since it works 100% of the time in ogg123, I feel I must have missed some corner case. My audio driver is almost always active. I usually have my music player going in the background when I do my testing. The problem

v3: - Kees Cook pointed out a weird side-effect: devices which have ->init() registered get their randomness added to the system each time they're switched in, but devices that don't have the init callback don't contribute to system randomness more than once. The weirdness is resolved here by using the randomness each time hwrng_init() is attempted, irrespective of

v3: - Kees Cook pointed out a weird side-effect: devices which have ->init() registered get their randomness added to the system each time they're switched in, but devices that don't have the init callback don't contribute to system randomness more than once. The weirdness is resolved here by using the randomness each time hwrng_init() is attempted, irrespective of

When I hotunplug a busy virtio-rng device or try to access hwrng attributes in non-smp guest, it gets stuck. My hotplug tests: | test 0: | hotunplug rng device from qemu monitor | | test 1: | guest) # dd if=/dev/hwrng of=/dev/null & | hotunplug rng device from qemu monitor | | test 2: | guest) # dd if=/dev/random of=/dev/null & | hotunplug rng device from qemu monitor | | test

When I hotunplug a busy virtio-rng device or try to access hwrng attributes in non-smp guest, it gets stuck. My hotplug tests: | test 0: | hotunplug rng device from qemu monitor | | test 1: | guest) # dd if=/dev/hwrng of=/dev/null & | hotunplug rng device from qemu monitor | | test 2: | guest) # dd if=/dev/random of=/dev/null & | hotunplug rng device from qemu monitor | | test

Commit d9e7972619334 "hwrng: add randomness to system from rng sources" added a call to rng_get_data() from the hwrng_register() function. However, some rng devices need initialization before data can be read from them. Also, the virtio-rng device does not behave properly when this call is made in its probe() routine - the virtio core sets the DRIVER_OK status bit only on a successful

When I hotunplug a busy virtio-rng device or try to access hwrng attributes in non-smp guest, it gets stuck. My original was pain, Rusty posted a real fix. This patchset fixed two issue in v1, and tested by my 6+ cases. | test 0: | hotunplug rng device from qemu monitor | | test 1: | guest) # dd if=/dev/hwrng of=/dev/null & | hotunplug rng device from qemu monitor | | test 2: |

When I hotunplug a busy virtio-rng device or try to access hwrng attributes in non-smp guest, it gets stuck. My original was pain, Rusty posted a real fix. This patchset fixed two issue in v1, and tested by my 6+ cases. | test 0: | hotunplug rng device from qemu monitor | | test 1: | guest) # dd if=/dev/hwrng of=/dev/null & | hotunplug rng device from qemu monitor | | test 2: |

When I hotunplug a busy virtio-rng device or try to access hwrng attributes in non-smp guest, it gets stuck. My hotplug tests: | test 0: | hotunplug rng device from qemu monitor | | test 1: | guest) # dd if=/dev/hwrng of=/dev/null & | hotunplug rng device from qemu monitor | | test 2: | guest) # dd if=/dev/random of=/dev/null & | hotunplug rng device from qemu monitor | | test

When I hotunplug a busy virtio-rng device or try to access hwrng attributes in non-smp guest, it gets stuck. My hotplug tests: | test 0: | hotunplug rng device from qemu monitor | | test 1: | guest) # dd if=/dev/hwrng of=/dev/null & | hotunplug rng device from qemu monitor | | test 2: | guest) # dd if=/dev/random of=/dev/null & | hotunplug rng device from qemu monitor | | test

Amos Kong <akong at redhat.com> writes: > I started a QEMU (non-smp) guest with one virtio-rng device, and read > random data from /dev/hwrng by dd: > > # dd if=/dev/hwrng of=/dev/null & > > In the same time, if I check hwrng attributes from sysfs by cat: > > # cat /sys/class/misc/hw_random/rng_* > > The cat process always gets stuck with slow backend (5

Amos Kong <akong at redhat.com> writes: > I started a QEMU (non-smp) guest with one virtio-rng device, and read > random data from /dev/hwrng by dd: > > # dd if=/dev/hwrng of=/dev/null & > > In the same time, if I check hwrng attributes from sysfs by cat: > > # cat /sys/class/misc/hw_random/rng_* > > The cat process always gets stuck with slow backend (5