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authorEric Auger <eric.auger@redhat.com>2017-01-19 20:57:59 +0000
committerWill Deacon <will.deacon@arm.com>2017-01-23 15:00:45 +0000
commitc7b41f0af38f53e46050b56a5b0e96710097b83c (patch)
tree11687bd608512ebc4e4dbfdf4056dddfaf6af902 /kernel/irq
parent88156f00904183d99e19269fbdb5cb56dc1522c3 (diff)
downloadlinux-c7b41f0af38f53e46050b56a5b0e96710097b83c.tar.bz2
irqdomain: irq_domain_check_msi_remap
This new function checks whether all MSI irq domains implement IRQ remapping. This is useful to understand whether VFIO passthrough is safe with respect to interrupts. On ARM typically an MSI controller can sit downstream to the IOMMU without preventing VFIO passthrough. As such any assigned device can write into the MSI doorbell. In case the MSI controller implements IRQ remapping, assigned devices will not be able to trigger interrupts towards the host. On the contrary, the assignment must be emphasized as unsafe with respect to interrupts. Signed-off-by: Eric Auger <eric.auger@redhat.com> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Tomasz Nowicki <tomasz.nowicki@caviumnetworks.com> Tested-by: Tomasz Nowicki <tomasz.nowicki@caviumnetworks.com> Tested-by: Bharat Bhushan <bharat.bhushan@nxp.com> Signed-off-by: Will Deacon <will.deacon@arm.com>
Diffstat (limited to 'kernel/irq')
-rw-r--r--kernel/irq/irqdomain.c25
1 files changed, 25 insertions, 0 deletions
diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c
index 876e13172dc8..80c4f9312187 100644
--- a/kernel/irq/irqdomain.c
+++ b/kernel/irq/irqdomain.c
@@ -278,6 +278,31 @@ struct irq_domain *irq_find_matching_fwspec(struct irq_fwspec *fwspec,
EXPORT_SYMBOL_GPL(irq_find_matching_fwspec);
/**
+ * irq_domain_check_msi_remap - Check whether all MSI irq domains implement
+ * IRQ remapping
+ *
+ * Return: false if any MSI irq domain does not support IRQ remapping,
+ * true otherwise (including if there is no MSI irq domain)
+ */
+bool irq_domain_check_msi_remap(void)
+{
+ struct irq_domain *h;
+ bool ret = true;
+
+ mutex_lock(&irq_domain_mutex);
+ list_for_each_entry(h, &irq_domain_list, link) {
+ if (irq_domain_is_msi(h) &&
+ !irq_domain_hierarchical_is_msi_remap(h)) {
+ ret = false;
+ break;
+ }
+ }
+ mutex_unlock(&irq_domain_mutex);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(irq_domain_check_msi_remap);
+
+/**
* irq_set_default_host() - Set a "default" irq domain
* @domain: default domain pointer
*