| From foo@baz Sun Jun 17 12:07:34 CEST 2018 |
| From: Jagannathan Raman <jag.raman@oracle.com> |
| Date: Tue, 6 Mar 2018 17:39:41 -0500 |
| Subject: iommu/vt-d: Fix usage of force parameter in intel_ir_reconfigure_irte() |
| |
| From: Jagannathan Raman <jag.raman@oracle.com> |
| |
| [ Upstream commit aa7528fe3576d11f4a10237178a723a1f080a547 ] |
| |
| It was noticed that the IRTE configured for guest OS kernel |
| was over-written while the guest was running. As a result, |
| vt-d Posted Interrupts configured for the guest are not being |
| delivered directly, and instead bounces off the host. Every |
| interrupt delivery takes a VM Exit. |
| |
| It was noticed that the following stack is doing the over-write: |
| [ 147.463177] modify_irte+0x171/0x1f0 |
| [ 147.463405] intel_ir_set_affinity+0x5c/0x80 |
| [ 147.463641] msi_domain_set_affinity+0x32/0x90 |
| [ 147.463881] irq_do_set_affinity+0x37/0xd0 |
| [ 147.464125] irq_set_affinity_locked+0x9d/0xb0 |
| [ 147.464374] __irq_set_affinity+0x42/0x70 |
| [ 147.464627] write_irq_affinity.isra.5+0xe1/0x110 |
| [ 147.464895] proc_reg_write+0x38/0x70 |
| [ 147.465150] __vfs_write+0x36/0x180 |
| [ 147.465408] ? handle_mm_fault+0xdf/0x200 |
| [ 147.465671] ? _cond_resched+0x15/0x30 |
| [ 147.465936] vfs_write+0xad/0x1a0 |
| [ 147.466204] SyS_write+0x52/0xc0 |
| [ 147.466472] do_syscall_64+0x74/0x1a0 |
| [ 147.466744] entry_SYSCALL_64_after_hwframe+0x3d/0xa2 |
| |
| reversing the sense of force check in intel_ir_reconfigure_irte() |
| restores proper posted interrupt functionality |
| |
| Signed-off-by: Jagannathan Raman <jag.raman@oracle.com> |
| Fixes: d491bdff888e ('iommu/vt-d: Reevaluate vector configuration on activate()') |
| Signed-off-by: Joerg Roedel <jroedel@suse.de> |
| Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| drivers/iommu/intel_irq_remapping.c | 2 +- |
| 1 file changed, 1 insertion(+), 1 deletion(-) |
| |
| --- a/drivers/iommu/intel_irq_remapping.c |
| +++ b/drivers/iommu/intel_irq_remapping.c |
| @@ -1136,7 +1136,7 @@ static void intel_ir_reconfigure_irte(st |
| irte->dest_id = IRTE_DEST(cfg->dest_apicid); |
| |
| /* Update the hardware only if the interrupt is in remapped mode. */ |
| - if (!force || ir_data->irq_2_iommu.mode == IRQ_REMAPPING) |
| + if (force || ir_data->irq_2_iommu.mode == IRQ_REMAPPING) |
| modify_irte(&ir_data->irq_2_iommu, irte); |
| } |
| |
