On 11.10.2021 20:18, Stefano Stabellini wrote: > On Mon, 11 Oct 2021, Jan Beulich wrote: >> On 11.10.2021 15:34, Bertrand Marquis wrote: >>>> On 11 Oct 2021, at 14:09, Jan Beulich <jbeul...@suse.com> wrote: >>>> On 11.10.2021 14:41, Bertrand Marquis wrote: >>>>> But digging deeper into this, I would have 2 questions: >>>>> >>>>> - msi_cleanup was done there after a request from Stefano, but is not >>>>> done in case or iommu error, is there an issue to solve here ? >>>> >>>> Maybe, but I'm not sure. This very much depends on what a domain >>>> could in principle do with a partly set-up device. Plus let's >>>> not forget that we're talking of only Dom0 here (for now at least, >>>> i.e. not considering the dom0less case). >>>> >>>> But I'd also like to further defer to Stefano. >>> >>> Ok, I must admit I do not really see at that stage why doing an MSI cleanup >>> could be needed so I will wait for Stefano to know if I need to keep this >>> when >>> moving the block up (at the end it is theoretical right now as this is >>> empty). > > I know that MSIs are not supported yet on ARM (pci_cleanup_msi does > nothing). But I wanted to make sure that the pci_cleanup_msi() calls are > present anywhere necessary, especially on the error paths. So that once > we add MSI support, we don't need to search through the code to find all > the error paths missing a pci_cleanup_msi() call. > > To answer your first question: you are right, we are also missing a > pci_cleanup_msi() call in the case of IOMMU error. So it might be better > to move the call to pci_cleanup_msi() under the "out" label so that we > can do it once for both cases. > > To answer your second point about whether it is necessary at all: if > MSIs and MSI-Xs cannot be already setup at this point at all (not even > the enable bit), then we don't need any call to pci_cleanup_msi() in > pci_add_device.
Well, at the very least MSI can't be set up ahead of the traps getting put in place. Whether partial success of putting traps in place may allow a cunning guest to set up MSI may depend on further aspects. Jan
