From: Marek Marczykowski-Górecki <marmarek@xxxxxxxxxxxxxxxxxxxxxx> [ Upstream commit 5e29500eba2aa19e1323df46f64dafcd4a327092 ] When Xen domain configures MSI-X, the usual approach is to enable MSI-X together with masking all of them via the config space, then fill the table and only then clear PCI_MSIX_FLAGS_MASKALL. Allow doing this via QEMU running in a stub domain. Previously, when changing PCI_MSIX_FLAGS_MASKALL was not allowed, the whole write was aborted, preventing change to the PCI_MSIX_FLAGS_ENABLE bit too. Note the Xen hypervisor intercepts this write anyway, and may keep the PCI_MSIX_FLAGS_MASKALL bit set if it wishes to. It will store the guest-requested state and will apply it eventually. Signed-off-by: Marek Marczykowski-Górecki <marmarek@xxxxxxxxxxxxxxxxxxxxxx> Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx> Link: https://lore.kernel.org/r/20221114103110.1519413-1-marmarek@xxxxxxxxxxxxxxxxxxxxxx Signed-off-by: Juergen Gross <jgross@xxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- drivers/xen/xen-pciback/conf_space_capability.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/drivers/xen/xen-pciback/conf_space_capability.c b/drivers/xen/xen-pciback/conf_space_capability.c index 5e53b4817f16..097316a74126 100644 --- a/drivers/xen/xen-pciback/conf_space_capability.c +++ b/drivers/xen/xen-pciback/conf_space_capability.c @@ -190,13 +190,16 @@ static const struct config_field caplist_pm[] = { }; static struct msi_msix_field_config { - u16 enable_bit; /* bit for enabling MSI/MSI-X */ - unsigned int int_type; /* interrupt type for exclusiveness check */ + u16 enable_bit; /* bit for enabling MSI/MSI-X */ + u16 allowed_bits; /* bits allowed to be changed */ + unsigned int int_type; /* interrupt type for exclusiveness check */ } msi_field_config = { .enable_bit = PCI_MSI_FLAGS_ENABLE, + .allowed_bits = PCI_MSI_FLAGS_ENABLE, .int_type = INTERRUPT_TYPE_MSI, }, msix_field_config = { .enable_bit = PCI_MSIX_FLAGS_ENABLE, + .allowed_bits = PCI_MSIX_FLAGS_ENABLE | PCI_MSIX_FLAGS_MASKALL, .int_type = INTERRUPT_TYPE_MSIX, }; @@ -229,7 +232,7 @@ static int msi_msix_flags_write(struct pci_dev *dev, int offset, u16 new_value, return 0; if (!dev_data->allow_interrupt_control || - (new_value ^ old_value) & ~field_config->enable_bit) + (new_value ^ old_value) & ~field_config->allowed_bits) return PCIBIOS_SET_FAILED; if (new_value & field_config->enable_bit) { -- 2.35.1
