This is a note to let you know that I've just added the patch titled
xen-pciback: Allow setting PCI_MSIX_FLAGS_MASKALL too
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
xen-pciback-allow-setting-pci_msix_flags_maskall-too.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 3af0d685af39ec22165e62d4372d3f3de337ffab
Author: Marek Marczykowski-Górecki <marmarek@xxxxxxxxxxxxxxxxxxxxxx>
Date: Mon Nov 14 11:31:08 2022 +0100
xen-pciback: Allow setting PCI_MSIX_FLAGS_MASKALL too
[ 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>
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) {
