From: Marek Marczykowski-Górecki Date: Thu, 26 Aug 2021 17:03:42 +0000 (+0200) Subject: PCI/MSI: Skip masking MSI-X on Xen PV X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=1a519dc7a73c977547d8b5108d98c6e769c89f4b;p=linux.git PCI/MSI: Skip masking MSI-X on Xen PV 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 Signed-off-by: Thomas Gleixner Acked-by: Bjorn Helgaas Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20210826170342.135172-1-marmarek@invisiblethingslab.com --- diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c index e5e75331b4155..3a9f4f8ad8f94 100644 --- a/drivers/pci/msi.c +++ b/drivers/pci/msi.c @@ -776,6 +776,9 @@ static void msix_mask_all(void __iomem *base, int tsize) 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); }