From: Thomas Gleixner Date: Thu, 28 Apr 2022 13:50:54 +0000 (+0200) Subject: x86/pci/xen: Disable PCI/MSI[-X] masking for XEN_HVM guests X-Git-Tag: archive/raspbian/5.10.113-1+rpi1^2~40 X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=509fb4a38588d1f82413ed979226cdbfa59889cf;p=linux.git x86/pci/xen: Disable PCI/MSI[-X] masking for XEN_HVM guests Origin: https://lore.kernel.org/linux-pci/87tuaduxj5.ffs@tglx Bug-Debian: https://bugs.debian.org/1006346 When a XEN_HVM guest uses the XEN PIRQ/Eventchannel mechanism, then PCI/MSI[-X] masking is solely controlled by the hypervisor, but contrary to XEN_PV guests this does not disable PCI/MSI[-X] masking in the PCI/MSI layer. This can lead to a situation where the PCI/MSI layer masks an MSI[-X] interrupt and the hypervisor grants the write despite the fact that it already requested the interrupt. As a consequence interrupt delivery on the affected device is not happening ever. Set pci_msi_ignore_mask to prevent that like it's done for XEN_PV guests already. Reported-by: Jeremi Piotrowski Reported-by: Dusty Mabe Reported-by: Salvatore Bonaccorso Fixes: 809f9267bbab ("xen: map MSIs into pirqs") Signed-off-by: Thomas Gleixner Cc: stable@vger.kernel.org Gbp-Pq: Topic bugfix/x86 Gbp-Pq: Name x86-pci-xen-Disable-PCI-MSI-X-masking-for-XEN_HVM-gu.patch --- diff --git a/arch/x86/pci/xen.c b/arch/x86/pci/xen.c index c552cd2d063..326d6d17373 100644 --- a/arch/x86/pci/xen.c +++ b/arch/x86/pci/xen.c @@ -476,7 +476,6 @@ static __init void xen_setup_pci_msi(void) xen_msi_ops.setup_msi_irqs = xen_setup_msi_irqs; } xen_msi_ops.teardown_msi_irqs = xen_pv_teardown_msi_irqs; - pci_msi_ignore_mask = 1; } else if (xen_hvm_domain()) { xen_msi_ops.setup_msi_irqs = xen_hvm_setup_msi_irqs; xen_msi_ops.teardown_msi_irqs = xen_teardown_msi_irqs; @@ -490,6 +489,11 @@ static __init void xen_setup_pci_msi(void) * in allocating the native domain and never use it. */ x86_init.irqs.create_pci_msi_domain = xen_create_pci_msi_domain; + /* + * With XEN PIRQ/Eventchannels in use PCI/MSI[-X] masking is solely + * controlled by the hypervisor. + */ + pci_msi_ignore_mask = 1; } #else /* CONFIG_PCI_MSI */