4.16-stable review patch. If anyone has any objections, please let me know.
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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); }