From 4f0750839421c64e3e3ab152cfd443f282682bc4 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Thu, 28 Apr 2022 15:50:54 +0200 Subject: [PATCH] x86/pci/xen: Disable PCI/MSI[-X] masking for XEN_HVM guests commit 7e0815b3e09986d2fe651199363e135b9358132a upstream. 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. Fixes: 809f9267bbab ("xen: map MSIs into pirqs") Reported-by: Jeremi Piotrowski Reported-by: Dusty Mabe Reported-by: Salvatore Bonaccorso Signed-off-by: Thomas Gleixner Tested-by: Noah Meyerhans Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/87tuaduxj5.ffs@tglx [nmeyerha@amazon.com: backported to 5.4] Signed-off-by: Noah Meyerhans Signed-off-by: Greg Kroah-Hartman --- arch/x86/pci/xen.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/arch/x86/pci/xen.c b/arch/x86/pci/xen.c index 5c11ae66b5d8..9cf8f5417e7f 100644 --- a/arch/x86/pci/xen.c +++ b/arch/x86/pci/xen.c @@ -442,6 +442,11 @@ void __init xen_msi_init(void) x86_msi.setup_msi_irqs = xen_hvm_setup_msi_irqs; x86_msi.teardown_msi_irq = xen_teardown_msi_irq; + /* + * With XEN PIRQ/Eventchannels in use PCI/MSI[-X] masking is solely + * controlled by the hypervisor. + */ + pci_msi_ignore_mask = 1; } #endif