[PATCH v2 6/8] x86/iommu: call pi_update_irte through an hvm_function callback

[Xenia Ragiadakou <burzalodowa@xxxxxxxxx>]

Posted interrupt support in Xen is currently implemented only for the
Intel platforms. Instead of calling directly pi_update_irte() from the
common hvm code, add a pi_update_irte callback to the hvm_function_table.
Then, create a wrapper function hvm_pi_update_irte() to be used by the
common hvm code.

In the pi_update_irte callback prototype, pass the vcpu as first parameter
instead of the posted-interrupt descriptor that is platform specific, and
remove the const qualifier from the parameter gvec since it is not needed
and because it does not compile with the alternative code patching in use.

Move the declaration of pi_update_irte() from asm/iommu.h to asm/hvm/vmx/vmx.h
since it is hvm and Intel specific.

No functional change intended.

Signed-off-by: Xenia Ragiadakou <burzalodowa@xxxxxxxxx>
---

Changes in v2:
  - remove the definition of hvm_pi_update_irte() for !CONFIG_HVM
  - replace CONFIG_INTEL_VTD with CONFIG_INTEL_IOMMU

 xen/arch/x86/hvm/vmx/vmx.c             | 10 ++++++++++
 xen/arch/x86/include/asm/hvm/hvm.h     | 15 +++++++++++++++
 xen/arch/x86/include/asm/hvm/vmx/vmx.h | 11 +++++++++++
 xen/arch/x86/include/asm/iommu.h       |  3 ---
 xen/drivers/passthrough/x86/hvm.c      |  5 ++---
 5 files changed, 38 insertions(+), 6 deletions(-)

diff --git a/xen/arch/x86/hvm/vmx/vmx.c b/xen/arch/x86/hvm/vmx/vmx.c
index 43a4865d1c..cb6b325e41 100644
--- a/xen/arch/x86/hvm/vmx/vmx.c
+++ b/xen/arch/x86/hvm/vmx/vmx.c
@@ -2143,6 +2143,14 @@ static bool cf_check vmx_test_pir(const struct vcpu *v, 
uint8_t vec)
     return pi_test_pir(vec, &v->arch.hvm.vmx.pi_desc);
 }
 
+static int cf_check vmx_pi_update_irte(const struct vcpu *v,
+                                       const struct pirq *pirq, uint8_t gvec)
+{
+    const struct pi_desc *pi_desc = v ? &v->arch.hvm.vmx.pi_desc : NULL;
+
+    return pi_update_irte(pi_desc, pirq, gvec);
+}
+
 static void cf_check vmx_handle_eoi(uint8_t vector, int isr)
 {
     uint8_t old_svi = set_svi(isr);
@@ -2591,6 +2599,8 @@ static struct hvm_function_table __initdata_cf_clobber 
vmx_function_table = {
     .tsc_scaling = {
         .max_ratio = VMX_TSC_MULTIPLIER_MAX,
     },
+
+    .pi_update_irte = vmx_pi_update_irte,
 };
 
 /* Handle VT-d posted-interrupt when VCPU is blocked. */
diff --git a/xen/arch/x86/include/asm/hvm/hvm.h 
b/xen/arch/x86/include/asm/hvm/hvm.h
index 93254651f2..b3fe0663f9 100644
--- a/xen/arch/x86/include/asm/hvm/hvm.h
+++ b/xen/arch/x86/include/asm/hvm/hvm.h
@@ -28,6 +28,8 @@
 #include <asm/x86_emulate.h>
 #include <asm/hvm/asid.h>
 
+struct pirq; /* needed by pi_update_irte */
+
 #ifdef CONFIG_HVM_FEP
 /* Permit use of the Forced Emulation Prefix in HVM guests */
 extern bool_t opt_hvm_fep;
@@ -250,6 +252,9 @@ struct hvm_function_table {
         /* Architecture function to setup TSC scaling ratio */
         void (*setup)(struct vcpu *v);
     } tsc_scaling;
+
+    int (*pi_update_irte)(const struct vcpu *v,
+                          const struct pirq *pirq, uint8_t gvec);
 };
 
 extern struct hvm_function_table hvm_funcs;
@@ -774,6 +779,16 @@ static inline void hvm_set_nonreg_state(struct vcpu *v,
         alternative_vcall(hvm_funcs.set_nonreg_state, v, nrs);
 }
 
+static inline int hvm_pi_update_irte(const struct vcpu *v,
+                                     const struct pirq *pirq, uint8_t gvec)
+{
+    if ( hvm_funcs.pi_update_irte )
+        return alternative_call(hvm_funcs.pi_update_irte, v, pirq, gvec);
+
+    return -EOPNOTSUPP;
+}
+
+
 #else  /* CONFIG_HVM */
 
 #define hvm_enabled false
diff --git a/xen/arch/x86/include/asm/hvm/vmx/vmx.h 
b/xen/arch/x86/include/asm/hvm/vmx/vmx.h
index 96a9f07ca5..e827fece07 100644
--- a/xen/arch/x86/include/asm/hvm/vmx/vmx.h
+++ b/xen/arch/x86/include/asm/hvm/vmx/vmx.h
@@ -146,6 +146,17 @@ static inline void pi_clear_sn(struct pi_desc *pi_desc)
     clear_bit(POSTED_INTR_SN, &pi_desc->control);
 }
 
+#ifdef CONFIG_INTEL_IOMMU
+int pi_update_irte(const struct pi_desc *pi_desc,
+                   const struct pirq *pirq, const uint8_t gvec);
+#else
+static inline int pi_update_irte(const struct pi_desc *pi_desc,
+                                 const struct pirq *pirq, const uint8_t gvec)
+{
+    return -EOPNOTSUPP;
+}
+#endif
+
 /*
  * Exit Reasons
  */
diff --git a/xen/arch/x86/include/asm/iommu.h b/xen/arch/x86/include/asm/iommu.h
index fb5fe4e1bf..b432790d24 100644
--- a/xen/arch/x86/include/asm/iommu.h
+++ b/xen/arch/x86/include/asm/iommu.h
@@ -131,9 +131,6 @@ void iommu_identity_map_teardown(struct domain *d);
 extern bool untrusted_msi;
 #endif
 
-int pi_update_irte(const struct pi_desc *pi_desc, const struct pirq *pirq,
-                   const uint8_t gvec);
-
 extern bool iommu_non_coherent, iommu_superpages;
 
 static inline void iommu_sync_cache(const void *addr, unsigned int size)
diff --git a/xen/drivers/passthrough/x86/hvm.c 
b/xen/drivers/passthrough/x86/hvm.c
index a16e0e5344..e720461a14 100644
--- a/xen/drivers/passthrough/x86/hvm.c
+++ b/xen/drivers/passthrough/x86/hvm.c
@@ -381,8 +381,7 @@ int pt_irq_create_bind(
 
         /* Use interrupt posting if it is supported. */
         if ( iommu_intpost )
-            pi_update_irte(vcpu ? &vcpu->arch.hvm.vmx.pi_desc : NULL,
-                           info, pirq_dpci->gmsi.gvec);
+            hvm_pi_update_irte(vcpu, info, pirq_dpci->gmsi.gvec);
 
         if ( pt_irq_bind->u.msi.gflags & XEN_DOMCTL_VMSI_X86_UNMASKED )
         {
@@ -672,7 +671,7 @@ int pt_irq_destroy_bind(
             what = "bogus";
     }
     else if ( pirq_dpci && pirq_dpci->gmsi.posted )
-        pi_update_irte(NULL, pirq, 0);
+        hvm_pi_update_irte(NULL, pirq, 0);
 
     if ( pirq_dpci && (pirq_dpci->flags & HVM_IRQ_DPCI_MAPPED) &&
          list_empty(&pirq_dpci->digl_list) )
-- 
2.37.2