From: Marek Marczykowski-Górecki Date: Tue, 25 Apr 2023 10:16:17 +0000 (+0200) Subject: x86/msi: clear initial MSI-X state on boot X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=913751d7af6e78d65c1e2adf4887193c827f0c5e;p=people%2Ftklengyel%2Fxen.git x86/msi: clear initial MSI-X state on boot Some firmware/devices are found to not reset MSI-X properly, leaving MASKALL set. Jason reports on his machine MASKALL persists through a warm reboot, but is cleared on cold boot. Xen relies on initial state being MASKALL clear. Especially, pci_reset_msix_state() assumes if MASKALL is set, it was Xen setting it due to msix->host_maskall or msix->guest_maskall. Clearing just MASKALL is risky if ENABLE is set, so clear them both. Reported-by: Jason Andryuk Signed-off-by: Marek Marczykowski-Górecki Reviewed-by: Jan Beulich Tested-by: Jason Andryuk --- diff --git a/xen/drivers/passthrough/msi.c b/xen/drivers/passthrough/msi.c index ce1a450f6f..fb78e2ebe8 100644 --- a/xen/drivers/passthrough/msi.c +++ b/xen/drivers/passthrough/msi.c @@ -46,6 +46,23 @@ int pdev_msi_init(struct pci_dev *pdev) spin_lock_init(&msix->table_lock); ctrl = pci_conf_read16(pdev->sbdf, msix_control_reg(pos)); + + if ( ctrl & (PCI_MSIX_FLAGS_MASKALL | PCI_MSIX_FLAGS_ENABLE) ) + { + /* + * pci_reset_msix_state() relies on MASKALL not being set + * initially, clear it (and ENABLE too - for safety), to meet that + * expectation. + */ + printk(XENLOG_WARNING + "%pp: unexpected initial MSI-X state (MASKALL=%d, ENABLE=%d), fixing\n", + &pdev->sbdf, + !!(ctrl & PCI_MSIX_FLAGS_MASKALL), + !!(ctrl & PCI_MSIX_FLAGS_ENABLE)); + ctrl &= ~(PCI_MSIX_FLAGS_ENABLE | PCI_MSIX_FLAGS_MASKALL); + pci_conf_write16(pdev->sbdf, msix_control_reg(pos), ctrl); + } + msix->nr_entries = msix_table_size(ctrl); pdev->msix = msix;