[PATCH 4.9 160/172] iommu/amd: Fix interrupt remapping when disable guest_mode

Greg Kroah-Hartman
2017-07-03T13:46:20Z

From: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>

commit 84a21dbdef0b96d773599c33c2afbb002198d303 upstream.

Pass-through devices to VM guest can get updated IRQ affinity
information via irq_set_affinity() when not running in guest mode.
Currently, AMD IOMMU driver in GA mode ignores the updated information
if the pass-through device is setup to use vAPIC regardless of guest_mode.
This could cause invalid interrupt remapping.

Also, the guest_mode bit should be set and cleared only when
SVM updates posted-interrupt interrupt remapping information.

Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Cc: Joerg Roedel <jroedel@suse.de>
Fixes: d98de49a53e48 ('iommu/amd: Enable vAPIC interrupt remapping mode by default')
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/iommu/amd_iommu.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)

--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -3857,11 +3857,9 @@ static void irte_ga_prepare(void *entry,
u8 vector, u32 dest_apicid, int devid)
{
struct irte_ga *irte = (struct irte_ga *) entry;
- struct iommu_dev_data *dev_data = search_dev_data(devid);

irte->lo.val = 0;
irte->hi.val = 0;
- irte->lo.fields_remap.guest_mode = dev_data ? dev_data->use_vapic : 0;
irte->lo.fields_remap.int_type = delivery_mode;
irte->lo.fields_remap.dm = dest_mode;
irte->hi.fields.vector = vector;
@@ -3917,10 +3915,10 @@ static void irte_ga_set_affinity(void *e
struct irte_ga *irte = (struct irte_ga *) entry;
struct iommu_dev_data *dev_data = search_dev_data(devid);

- if (!dev_data || !dev_data->use_vapic) {
+ if (!dev_data || !dev_data->use_vapic ||
+ !irte->lo.fields_remap.guest_mode) {
irte->hi.fields.vector = vector;
irte->lo.fields_remap.destination = dest_apicid;
- irte->lo.fields_remap.guest_mode = 0;
modify_irte_ga(devid, index, irte, NULL);
}
}