uio_pci_generic: extensions to allow access for non-privileged processes
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From: Joerg Roedel on 1 Apr 2010 16:30 On Thu, Apr 01, 2010 at 12:24:45PM -0700, Tom Lyon wrote: > For my purposes, collapsing all the MSI-Xs into one MSI-look-alike is fine, > because I'd be using MSI anyways if I could. The weird Intel 82599 VF only > supports MSI-X. For KVM this is not fine. The device should look in the guest as it looks in the host. Some devices might only support MSI-X and thus the drivers for it only search for MSI-X and get confused when they only find MSI. > So one big question is - do we expand the whole UIO framework for KVM > requirements, or do we split off either KVM or non-VM into a separate driver? > Hans or Greg - care to opine? We should definitly work towards a single implementation. The KVM device passthrough requirements are not very different from that of userspace device access. Joerg -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Greg KH on 2 Apr 2010 13:10 On Fri, Apr 02, 2010 at 09:43:35AM +0300, Avi Kivity wrote: > On 04/01/2010 10:24 PM, Tom Lyon wrote: >> >>> But there are multiple msi-x interrupts, how do you know which one >>> triggered? >>> >> You don't. This would suck for KVM, I guess, but we'd need major rework of the >> generic UIO stuff to have a separate event channel for each MSI-X. >> > > Doesn't it suck for non-kvm in the same way? Multiple vectors are there > for a reason. For example, if you have a multiqueue NIC, you'd have to > process all queues instead of just the one that triggered. > >> For my purposes, collapsing all the MSI-Xs into one MSI-look-alike is fine, >> because I'd be using MSI anyways if I could. The weird Intel 82599 VF only >> supports MSI-X. >> >> So one big question is - do we expand the whole UIO framework for KVM >> requirements, or do we split off either KVM or non-VM into a separate driver? >> Hans or Greg - care to opine? >> > > Currently kvm does device assignment with its own code, I'd like to unify > it with uio, not split it off. > > Separate notifications for msi-x interrupts are just as useful for uio as > they are for kvm. I agree, there should not be a difference here for KVM vs. the "normal" version. thanks, greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Joerg Roedel on 9 Apr 2010 05:10
Btw. This patch posting is broken. It suffers from line-wraps which make it impossible to apply as-is. I was able to fix it but please consider this in your next posting. On Wed, Mar 31, 2010 at 05:12:35PM -0700, Tom Lyon wrote: > --- linux-2.6.33/drivers/uio/uio_pci_generic.c 2010-02-24 > 10:52:17.000000000 -0800 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Unexpected line-wrap. I also got some whitespace warnings when trying to apply it. Please make sure you fix this in the next version too. Thanks, Joerg -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |