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Then it disables INTx just before clearing MASKALL bit. Currently this approach is rejected by xen-pciback. According to the PCIe spec, device cannot use INTx when MSI/MSI-X is enabled (in other words: enabling MSI/MSI-X implicitly disables INTx). Change the logic to consider INTx disabled if MSI/MSI-X is enabled. This applies to three places: - checking currently enabled interrupts type, - transition to MSI/MSI-X - where INTx would be implicitly disabled, - clearing INTx disable bit - which can be allowed even if MSI/MSI-X is enabled, as device should consider INTx disabled anyway in that case Fixes: 5e29500eba2a ("xen-pciback: Allow setting PCI_MSIX_FLAGS_MASKALL too") Signed-off-by: Marek Marczykowski-Górecki Acked-by: Juergen Gross --- Changes in v3: - allow clearing INTx regardless of MSI/MSI-X state, to be consistent with enabling MSI/MSI-X Changes in v2: - restructure the patch to consider not only MASKALL bit, but enabling MSI/MSI-X generally, without explicitly disabling INTx first --- drivers/xen/xen-pciback/conf_space.c | 19 +++++++++++------ .../xen/xen-pciback/conf_space_capability.c | 3 ++- drivers/xen/xen-pciback/conf_space_header.c | 21 +++---------------- 3 files changed, 18 insertions(+), 25 deletions(-) diff --git a/drivers/xen/xen-pciback/conf_space.c b/drivers/xen/xen-pciback/conf_space.c index 059de92aea7d..d47eee6c5143 100644 --- a/drivers/xen/xen-pciback/conf_space.c +++ b/drivers/xen/xen-pciback/conf_space.c @@ -288,12 +288,6 @@ int xen_pcibk_get_interrupt_type(struct pci_dev *dev) u16 val; int ret = 0; - err = pci_read_config_word(dev, PCI_COMMAND, &val); - if (err) - return err; - if (!(val & PCI_COMMAND_INTX_DISABLE)) - ret |= INTERRUPT_TYPE_INTX; - /* * Do not trust dev->msi(x)_enabled here, as enabling could be done * bypassing the pci_*msi* functions, by the qemu. @@ -316,6 +310,19 @@ int xen_pcibk_get_interrupt_type(struct pci_dev *dev) if (val & PCI_MSIX_FLAGS_ENABLE) ret |= INTERRUPT_TYPE_MSIX; } + + /* + * PCIe spec says device cannot use INTx if MSI/MSI-X is enabled, + * so check for INTx only when both are disabled. + */ + if (!ret) { + err = pci_read_config_word(dev, PCI_COMMAND, &val); + if (err) + return err; + if (!(val & PCI_COMMAND_INTX_DISABLE)) + ret |= INTERRUPT_TYPE_INTX; + } + return ret ?: INTERRUPT_TYPE_NONE; } diff --git a/drivers/xen/xen-pciback/conf_space_capability.c b/drivers/xen/xen-pciback/conf_space_capability.c index 097316a74126..eb4c1af44f5c 100644 --- a/drivers/xen/xen-pciback/conf_space_capability.c +++ b/drivers/xen/xen-pciback/conf_space_capability.c @@ -236,10 +236,11 @@ static int msi_msix_flags_write(struct pci_dev *dev, int offset, u16 new_value, return PCIBIOS_SET_FAILED; if (new_value & field_config->enable_bit) { - /* don't allow enabling together with other interrupt types */ + /* don't allow enabling together with other interrupt type */ int int_type = xen_pcibk_get_interrupt_type(dev); if (int_type == INTERRUPT_TYPE_NONE || + int_type == INTERRUPT_TYPE_INTX || int_type == field_config->int_type) goto write; return PCIBIOS_SET_FAILED; diff --git a/drivers/xen/xen-pciback/conf_space_header.c b/drivers/xen/xen-pciback/conf_space_header.c index 981435103af1..fc0332645966 100644 --- a/drivers/xen/xen-pciback/conf_space_header.c +++ b/drivers/xen/xen-pciback/conf_space_header.c @@ -104,24 +104,9 @@ static int command_write(struct pci_dev *dev, int offset, u16 value, void *data) pci_clear_mwi(dev); } - if (dev_data && dev_data->allow_interrupt_control) { - if ((cmd->val ^ value) & PCI_COMMAND_INTX_DISABLE) { - if (value & PCI_COMMAND_INTX_DISABLE) { - pci_intx(dev, 0); - } else { - /* Do not allow enabling INTx together with MSI or MSI-X. */ - switch (xen_pcibk_get_interrupt_type(dev)) { - case INTERRUPT_TYPE_NONE: - pci_intx(dev, 1); - break; - case INTERRUPT_TYPE_INTX: - break; - default: - return PCIBIOS_SET_FAILED; - } - } - } - } + if (dev_data && dev_data->allow_interrupt_control && + ((cmd->val ^ value) & PCI_COMMAND_INTX_DISABLE)) + pci_intx(dev, !(value & PCI_COMMAND_INTX_DISABLE)); cmd->val = value;