From: Marek Marczykowski-Górecki marmarek@invisiblethingslab.com
commit 1a519dc7a73c977547d8b5108d98c6e769c89f4b upstream.
When running as Xen PV guest, masking MSI-X is a responsibility of the hypervisor. The guest has no write access to the relevant BAR at all - when it tries to, it results in a crash like this:
BUG: unable to handle page fault for address: ffffc9004069100c #PF: supervisor write access in kernel mode #PF: error_code(0x0003) - permissions violation RIP: e030:__pci_enable_msix_range.part.0+0x26b/0x5f0 e1000e_set_interrupt_capability+0xbf/0xd0 [e1000e] e1000_probe+0x41f/0xdb0 [e1000e] local_pci_probe+0x42/0x80 (...)
The recently introduced function msix_mask_all() does not check the global variable pci_msi_ignore_mask which is set by XEN PV to bypass the masking of MSI[-X] interrupts.
Add the check to make this function XEN PV compatible.
Fixes: 7d5ec3d36123 ("PCI/MSI: Mask all unused MSI-X entries") Signed-off-by: Marek Marczykowski-Górecki marmarek@invisiblethingslab.com Signed-off-by: Thomas Gleixner tglx@linutronix.de Acked-by: Bjorn Helgaas bhelgaas@google.com Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20210826170342.135172-1-marmarek@invisiblethingsla... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/pci/msi.c | 3 +++ 1 file changed, 3 insertions(+)
--- a/drivers/pci/msi.c +++ b/drivers/pci/msi.c @@ -748,6 +748,9 @@ static void msix_mask_all(void __iomem * u32 ctrl = PCI_MSIX_ENTRY_CTRL_MASKBIT; int i;
+ if (pci_msi_ignore_mask) + return; + for (i = 0; i < tsize; i++, base += PCI_MSIX_ENTRY_SIZE) writel(ctrl, base + PCI_MSIX_ENTRY_VECTOR_CTRL); }