[Xen-devel] [v3 10/15] vt-d: Add API to update IRTE when VT-d PI is used

[Feng Wu <feng.wu@xxxxxxxxx>]

This patch adds an API which is used to update the IRTE
for posted-interrupt when guest changes MSI/MSI-X information.

Signed-off-by: Feng Wu <feng.wu@xxxxxxxxx>
---
v3:
- Remove "adding PDA_MASK()" when updating 'pda_l' and 'pda_h' for IRTE.
- Change the return type of pi_update_irte() to int.
- Remove some pointless printk message in pi_update_irte().
- Use structure assignment instead of memcpy() for irte copy.

 xen/drivers/passthrough/vtd/intremap.c | 98 ++++++++++++++++++++++++++++++++++
 xen/drivers/passthrough/vtd/iommu.h    |  2 +
 xen/include/asm-x86/iommu.h            |  2 +
 3 files changed, 102 insertions(+)

diff --git a/xen/drivers/passthrough/vtd/intremap.c 
b/xen/drivers/passthrough/vtd/intremap.c
index b7a42f6..401a9d1 100644
--- a/xen/drivers/passthrough/vtd/intremap.c
+++ b/xen/drivers/passthrough/vtd/intremap.c
@@ -900,3 +900,101 @@ void iommu_disable_x2apic_IR(void)
     for_each_drhd_unit ( drhd )
         disable_qinval(drhd->iommu);
 }
+
+static inline void setup_posted_irte(
+    struct iremap_entry *new_ire, struct pi_desc *pi_desc, uint8_t gvec)
+{
+    new_ire->post.urg = 0;
+    new_ire->post.vector = gvec;
+    new_ire->post.pda_l = virt_to_maddr(pi_desc) >> (32 - PDA_LOW_BIT);
+    new_ire->post.pda_h = virt_to_maddr(pi_desc) >> 32;
+
+    new_ire->post.res_1 = 0;
+    new_ire->post.res_2 = 0;
+    new_ire->post.res_3 = 0;
+    new_ire->post.res_4 = 0;
+    new_ire->post.res_5 = 0;
+
+    new_ire->post.im = 1;
+}
+
+/*
+ * This function is used to update the IRTE for posted-interrupt
+ * when guest changes MSI/MSI-X information.
+ */
+int pi_update_irte(struct vcpu *v, struct pirq *pirq, uint8_t gvec)
+{
+    struct irq_desc *desc;
+    struct msi_desc *msi_desc;
+    int remap_index;
+    int rc = 0;
+    struct pci_dev *pci_dev;
+    struct acpi_drhd_unit *drhd;
+    struct iommu *iommu;
+    struct ir_ctrl *ir_ctrl;
+    struct iremap_entry *iremap_entries = NULL, *p = NULL;
+    struct iremap_entry new_ire;
+    struct pi_desc *pi_desc = &v->arch.hvm_vmx.pi_desc;
+    unsigned long flags;
+    uint128_t old_ire, ret;
+
+    desc = pirq_spin_lock_irq_desc(pirq, NULL);
+    if ( !desc )
+        return -ENOMEM;
+
+    msi_desc = desc->msi_desc;
+    if ( !msi_desc )
+    {
+        rc = -EBADSLT;
+        goto unlock_out;
+    }
+
+    pci_dev = msi_desc->dev;
+    if ( !pci_dev )
+    {
+        rc = -ENODEV;
+        goto unlock_out;
+    }
+
+    remap_index = msi_desc->remap_index;
+    drhd = acpi_find_matched_drhd_unit(pci_dev);
+    if ( !drhd )
+    {
+        rc = -ENODEV;
+        goto unlock_out;
+    }
+
+    iommu = drhd->iommu;
+    ir_ctrl = iommu_ir_ctrl(iommu);
+    if ( !ir_ctrl )
+    {
+        rc = -ENODEV;
+        goto unlock_out;
+    }
+
+    spin_lock_irqsave(&ir_ctrl->iremap_lock, flags);
+
+    GET_IREMAP_ENTRY(ir_ctrl->iremap_maddr, remap_index, iremap_entries, p);
+    new_ire = *p;
+
+    /* Setup/Update interrupt remapping table entry. */
+    setup_posted_irte(&new_ire, pi_desc, gvec);
+
+    do {
+        old_ire = *(uint128_t *)p;
+        ret = cmpxchg16b(p, &old_ire, &new_ire);
+    } while ( memcmp(&ret, &old_ire, sizeof(old_ire)) );
+
+    iommu_flush_cache_entry(p, sizeof(struct iremap_entry));
+    iommu_flush_iec_index(iommu, 0, remap_index);
+
+    if ( iremap_entries )
+        unmap_vtd_domain_page(iremap_entries);
+
+    spin_unlock_irqrestore(&ir_ctrl->iremap_lock, flags);
+
+ unlock_out:
+    spin_unlock_irq(&desc->lock);
+
+    return rc;
+}
diff --git a/xen/drivers/passthrough/vtd/iommu.h 
b/xen/drivers/passthrough/vtd/iommu.h
index 49daa70..9ce941e 100644
--- a/xen/drivers/passthrough/vtd/iommu.h
+++ b/xen/drivers/passthrough/vtd/iommu.h
@@ -329,6 +329,8 @@ struct iremap_entry {
   };
 };
 
+#define PDA_LOW_BIT    26
+
 /* Max intr remapping table page order is 8, as max number of IRTEs is 64K */
 #define IREMAP_PAGE_ORDER  8
 
diff --git a/xen/include/asm-x86/iommu.h b/xen/include/asm-x86/iommu.h
index e7a65da..2a1523e 100644
--- a/xen/include/asm-x86/iommu.h
+++ b/xen/include/asm-x86/iommu.h
@@ -32,6 +32,8 @@ int iommu_supports_eim(void);
 int iommu_enable_x2apic_IR(void);
 void iommu_disable_x2apic_IR(void);
 
+int pi_update_irte(struct vcpu *v, struct pirq *pirq, uint8_t gvec);
+
 #endif /* !__ARCH_X86_IOMMU_H__ */
 /*
  * Local variables:
-- 
2.1.0


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