Commit 5e29500e authored by Marek Marczykowski-Górecki's avatar Marek Marczykowski-Górecki Committed by Juergen Gross
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xen-pciback: Allow setting PCI_MSIX_FLAGS_MASKALL too 



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: default avatarMarek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Reviewed-by: default avatarJan Beulich <jbeulich@suse.com>
Link: https://lore.kernel.org/r/20221114103110.1519413-1-marmarek@invisiblethingslab.com


Signed-off-by: default avatarJuergen Gross <jgross@suse.com>
parent da36a2a7

drivers/xen/xen-pciback/conf_space_capability.c

+6 −3
Original line number Diff line number Diff line
@@ -191,12 +191,15 @@ static const struct config_field caplist_pm[] = { 


static struct msi_msix_field_config {

	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) {