[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH for-4.13 v2] passthrough: simplify locking and logging
> -----Original Message----- > From: Andrew Cooper <andrew.cooper3@xxxxxxxxxx> > Sent: 04 November 2019 11:06 > To: Durrant, Paul <pdurrant@xxxxxxxxxx>; xen-devel@xxxxxxxxxxxxxxxxxxxx > Cc: Igor Druzhinin <igor.druzhinin@xxxxxxxxxx>; jgross@xxxxxxxx; > jbeulich@xxxxxxxx > Subject: Re: [Xen-devel] [PATCH for-4.13 v2] passthrough: simplify locking > and logging > > On 04/11/2019 08:31, Durrant, Paul wrote: > >> -----Original Message----- > >> From: Igor Druzhinin <igor.druzhinin@xxxxxxxxxx> > >> Sent: 01 November 2019 19:28 > >> To: xen-devel@xxxxxxxxxxxxxxxxxxxx > >> Cc: Durrant, Paul <pdurrant@xxxxxxxxxx>; jbeulich@xxxxxxxx; > >> jgross@xxxxxxxx > >> Subject: [PATCH for-4.13 v2] passthrough: simplify locking and logging > >> > >> From: Paul Durrant <pdurrant@xxxxxxxxxx> > >> > >> Dropping the pcidevs lock between calling device_assigned() and > >> assign_device() means that the latter has to do the same check as the > >> former for no obvious gain. Also, since long running operations under > >> pcidevs lock already drop the lock and return -ERESTART periodically > there > >> is little point in immediately failing an assignment operation with > >> -ERESTART just because the pcidevs lock could not be acquired (for the > >> second time, having already blocked on acquiring the lock in > >> device_assigned()). > >> > >> This patch instead acquires the lock once for assignment (or test > assign) > >> operations directly in iommu_do_pci_domctl() and thus can remove the > >> duplicate domain ownership check in assign_device(). Whilst in the > >> neighbourhood, the patch also removes some debug logging from > >> assign_device() and deassign_device() and replaces it with proper error > >> logging, which allows error logging in iommu_do_pci_domctl() to be > >> removed. Also, since device_assigned() can tell the difference between > a > >> guest assigned device and a non-existent one, log the actual error > >> condition rather then being ambiguous for the sake a few extra lines of > >> code. > >> > >> Signed-off-by: Paul Durrant <pdurrant@xxxxxxxxxx> > >> --- > >> > >> This is XSA-302 followup and contains some changes important for > >> XenServer. > >> Juergen, could this be considered for 4.13 inclusion? > >> > >> v2: updated Paul's email address > > This was work you did at Citrix, yes? > > > Reviewed-by: Paul Durrant <pdurrant@xxxxxxxxxx> > > SoB and R-by? I did do the work while I was at Citrix, but surely the SoB must be updated since the patch is only now being posted? As for the R-b, why should that be historic? Paul > > ~Andrew _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxxx https://lists.xenproject.org/mailman/listinfo/xen-devel
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