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 <[email protected]>
Reported-by: Dusty Mabe <[email protected]>
Reported-by: Salvatore Bonaccorso <[email protected]>
Fixes: 809f9267bbab ("xen: map MSIs into pirqs")
Signed-off-by: Thomas Gleixner <[email protected]>
Cc: [email protected]
---
arch/x86/pci/xen.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
--- a/arch/x86/pci/xen.c
+++ b/arch/x86/pci/xen.c
@@ -467,7 +467,6 @@ static __init void xen_setup_pci_msi(voi
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(voi
* 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 */
The following commit has been merged into the x86/urgent branch of tip:
Commit-ID: 7e0815b3e09986d2fe651199363e135b9358132a
Gitweb: https://git.kernel.org/tip/7e0815b3e09986d2fe651199363e135b9358132a
Author: Thomas Gleixner <[email protected]>
AuthorDate: Thu, 28 Apr 2022 15:50:54 +02:00
Committer: Thomas Gleixner <[email protected]>
CommitterDate: Fri, 29 Apr 2022 14:37:39 +02:00
x86/pci/xen: Disable PCI/MSI[-X] masking for XEN_HVM guests
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 <[email protected]>
Reported-by: Dusty Mabe <[email protected]>
Reported-by: Salvatore Bonaccorso <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Tested-by: Noah Meyerhans <[email protected]>
Cc: [email protected]
Link: https://lore.kernel.org/r/87tuaduxj5.ffs@tglx
---
arch/x86/pci/xen.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/arch/x86/pci/xen.c b/arch/x86/pci/xen.c
index 9bb1e29..b94f727 100644
--- a/arch/x86/pci/xen.c
+++ b/arch/x86/pci/xen.c
@@ -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 */