[Qemu-devel] [PATCH 19/18] intel_iommu: Add support for Extended Interrupt Mode

[Jan Kiszka <jan.kiszka@siemens.com>]

As neither QEMU nor KVM support more than 255 CPUs so far, this is
simple: we only need to switch the destination ID translation in
vtd_remap_irq_get if EIME is set.

Once CFI support is there, it will have to take EIM into account as
well. So far, nothing to do for this.

This patch allows to use x2APIC in split irqchip mode of KVM.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
---

Include in v6 - if you like to. Keep for later otherwise.

 hw/i386/intel_iommu.c          | 16 +++++++++-------
 hw/i386/intel_iommu_internal.h |  2 ++
 include/hw/i386/intel_iommu.h  |  1 +
 3 files changed, 12 insertions(+), 7 deletions(-)

diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
index 7122e5b..23bae30 100644
--- a/hw/i386/intel_iommu.c
+++ b/hw/i386/intel_iommu.c
@@ -922,6 +922,7 @@ static void vtd_interrupt_remap_table_setup(IntelIOMMUState *s)
     value = vtd_get_quad_raw(s, DMAR_IRTA_REG);
     s->intr_size = 1UL << ((value & VTD_IRTA_SIZE_MASK) + 1);
     s->intr_root = value & VTD_IRTA_ADDR_MASK;
+    s->intr_eime = value & VTD_IRTA_EIME;
 
     /* Notify global invalidation */
     vtd_iec_notify_all(s, true, 0, 0);
@@ -2056,11 +2057,13 @@ static int vtd_remap_irq_get(IntelIOMMUState *iommu, uint16_t index, VTDIrq *irq
     irq->trigger_mode = irte.trigger_mode;
     irq->vector = irte.vector;
     irq->delivery_mode = irte.delivery_mode;
-    /* Not support EIM yet: please refer to vt-d 9.10 DST bits */
+    irq->dest = irte.dest_id;
+    if (!iommu->intr_eime) {
 #define  VTD_IR_APIC_DEST_MASK         (0xff00ULL)
 #define  VTD_IR_APIC_DEST_SHIFT        (8)
-    irq->dest = (irte.dest_id & VTD_IR_APIC_DEST_MASK) >> \
-        VTD_IR_APIC_DEST_SHIFT;
+        irq->dest = (irq->dest & VTD_IR_APIC_DEST_MASK) >>
+            VTD_IR_APIC_DEST_SHIFT;
+    }
     irq->dest_mode = irte.dest_mode;
     irq->redir_hint = irte.redir_hint;
 
@@ -2327,7 +2330,7 @@ static void vtd_init(IntelIOMMUState *s)
     s->ecap = VTD_ECAP_QI | VTD_ECAP_IRO;
 
     if (ms->iommu_intr) {
-        s->ecap |= VTD_ECAP_IR;
+        s->ecap |= VTD_ECAP_IR | VTD_ECAP_EIM;
     }
 
     vtd_reset_context_cache(s);
@@ -2381,10 +2384,9 @@ static void vtd_init(IntelIOMMUState *s)
     vtd_define_quad(s, DMAR_FRCD_REG_0_2, 0, 0, 0x8000000000000000ULL);
 
     /*
-     * Interrupt remapping registers, not support extended interrupt
-     * mode for now.
+     * Interrupt remapping registers.
      */
-    vtd_define_quad(s, DMAR_IRTA_REG, 0, 0xfffffffffffff00fULL, 0);
+    vtd_define_quad(s, DMAR_IRTA_REG, 0, 0xfffffffffffff80fULL, 0);
 }
 
 /* Should not reset address_spaces when reset because devices will still use
diff --git a/hw/i386/intel_iommu_internal.h b/hw/i386/intel_iommu_internal.h
index 10c20fe..72b0114 100644
--- a/hw/i386/intel_iommu_internal.h
+++ b/hw/i386/intel_iommu_internal.h
@@ -176,6 +176,7 @@
 
 /* IRTA_REG */
 #define VTD_IRTA_ADDR_MASK          (VTD_HAW_MASK ^ 0xfffULL)
+#define VTD_IRTA_EIME               (1ULL << 11)
 #define VTD_IRTA_SIZE_MASK          (0xfULL)
 
 /* ECAP_REG */
@@ -184,6 +185,7 @@
 #define VTD_ECAP_QI                 (1ULL << 1)
 /* Interrupt Remapping support */
 #define VTD_ECAP_IR                 (1ULL << 3)
+#define VTD_ECAP_EIM                (1ULL << 4)
 
 /* CAP_REG */
 /* (offset >> 4) << 24 */
diff --git a/include/hw/i386/intel_iommu.h b/include/hw/i386/intel_iommu.h
index 4fe92cf..c0c5819 100644
--- a/include/hw/i386/intel_iommu.h
+++ b/include/hw/i386/intel_iommu.h
@@ -261,6 +261,7 @@ struct IntelIOMMUState {
     bool intr_enabled;              /* Whether guest enabled IR */
     dma_addr_t intr_root;           /* Interrupt remapping table pointer */
     uint32_t intr_size;             /* Number of IR table entries */
+    bool intr_eime;                 /* Extended interrupt mode enabled */
     QLIST_HEAD(, VTD_IEC_Notifier) iec_notifiers; /* IEC notify list */
 };
 
-- 
2.1.4