Messages in this thread Patch in this message | | | From | Suravee Suthikulpanit <> | Subject | [PATCH v2] iommu/amd: Restore IRTE.RemapEn bit for amd_iommu_activate_guest_mode | Date | Wed, 16 Sep 2020 11:17:20 +0000 |
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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.
Reported-by: Maxim Levitsky <mlevitsk@redhat.com> Tested-by: Maxim Levitsky <mlevitsk@redhat.com> Cc: Joao Martins <joao.m.martins@oracle.com> Fixes: e52d58d54a321 ("iommu/amd: Use cmpxchg_double() when updating 128-bit IRTE") Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com> --- 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 e938677af8bc..db4fb840c59c 100644 --- a/drivers/iommu/amd/iommu.c +++ b/drivers/iommu/amd/iommu.c @@ -3900,14 +3900,18 @@ 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; -- 2.17.1
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