From: Suravee Suthikulpanit suravee.suthikulpanit@amd.com
[ Upstream commit e97685abd5d711c885053d4949178f7ab9acbaef ]
Commit e52d58d54a32 ("iommu/amd: Use cmpxchg_double() when updating 128-bit IRTE") removed an assumption that modify_irte_ga always set the valid bit, which requires the callers to set the appropriate value for the struct irte_ga.valid bit before calling the function.
Similar to the commit 26e495f34107 ("iommu/amd: Restore IRTE.RemapEn bit after programming IRTE"), which is for the function amd_iommu_deactivate_guest_mode().
The same change is also needed for the amd_iommu_activate_guest_mode(). Otherwise, this could trigger IO_PAGE_FAULT for the VFIO based VMs with AVIC enabled.
Fixes: e52d58d54a321 ("iommu/amd: Use cmpxchg_double() when updating 128-bit IRTE") Reported-by: Maxim Levitsky mlevitsk@redhat.com Signed-off-by: Suravee Suthikulpanit suravee.suthikulpanit@amd.com Tested-by: Maxim Levitsky mlevitsk@redhat.com Reviewed-by: Joao Martins joao.m.martins@oracle.com Reviewed-by: Maxim Levitsky mlevitsk@redhat.com Cc: Joao Martins joao.m.martins@oracle.com Link: https://lore.kernel.org/r/20200916111720.43913-1-suravee.suthikulpanit@amd.c... Signed-off-by: Joerg Roedel jroedel@suse.de Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/iommu/amd/iommu.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c index 48fe272da6e9c..a51dcf26b09f2 100644 --- a/drivers/iommu/amd/iommu.c +++ b/drivers/iommu/amd/iommu.c @@ -3831,14 +3831,18 @@ int amd_iommu_activate_guest_mode(void *data) { struct amd_ir_data *ir_data = (struct amd_ir_data *)data; struct irte_ga *entry = (struct irte_ga *) ir_data->entry; + u64 valid;
if (!AMD_IOMMU_GUEST_IR_VAPIC(amd_iommu_guest_ir) || !entry || entry->lo.fields_vapic.guest_mode) return 0;
+ valid = entry->lo.fields_vapic.valid; + entry->lo.val = 0; entry->hi.val = 0;
+ entry->lo.fields_vapic.valid = valid; entry->lo.fields_vapic.guest_mode = 1; entry->lo.fields_vapic.ga_log_intr = 1; entry->hi.fields.ga_root_ptr = ir_data->ga_root_ptr;