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x86/pci/xen: Disable PCI/MSI[-X] masking for XEN_HVM guests

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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: 809f9267bb ("xen: map MSIs into pirqs")
Reported-by: Jeremi Piotrowski <jpiotrowski@linux.microsoft.com>
Reported-by: Dusty Mabe <dustymabe@redhat.com>
Reported-by: Salvatore Bonaccorso <carnil@debian.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Noah Meyerhans <noahm@debian.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/87tuaduxj5.ffs@tglx
This commit is contained in:
Thomas Gleixner 2022-04-28 15:50:54 +02:00
parent 1fa568e26f
commit 7e0815b3e0
1 changed files with 5 additions and 1 deletions
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6
arch/x86/pci/xen.c
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@ -467,7 +467,6 @@ static __init void xen_setup_pci_msi(void)
else
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;
@ -481,6 +480,11 @@ 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 */