[Xen-devel] [PATCH v2 27/30] x86/msixtbl: disable MSI-X intercepts for domains without an ioreq server

[Roger Pau Monne <roger.pau@xxxxxxxxxx>]

The current msixtbl intercepts only partially trap MSI-X accesses, but are
not complete, there's missing logic in order to setup PIRQs and bind them to
domains. Disable them for domains without at least an ioreq server (PVH).

Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
---
Cc: Paul Durrant <paul.durrant@xxxxxxxxxx>
Cc: Jan Beulich <jbeulich@xxxxxxxx>
Cc: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
NB: this is a preparatory patch for introducing a complete MSI-X emulation
layer into Xen. Long term the current msixtbl code should be replaced with
the complete MSI-X emulation introduced in later patches.
---
 xen/arch/x86/hvm/ioreq.c        | 11 +++++++++++
 xen/drivers/passthrough/io.c    |  4 +++-
 xen/include/asm-x86/hvm/ioreq.h |  1 +
 3 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/xen/arch/x86/hvm/ioreq.c b/xen/arch/x86/hvm/ioreq.c
index d2245e2..b09fa96 100644
--- a/xen/arch/x86/hvm/ioreq.c
+++ b/xen/arch/x86/hvm/ioreq.c
@@ -772,6 +772,17 @@ int hvm_destroy_ioreq_server(struct domain *d, ioservid_t 
id)
     return rc;
 }
 
+int hvm_has_ioreq_server(struct domain *d)
+{
+    int empty;
+
+    spin_lock_recursive(&d->arch.hvm_domain.ioreq_server.lock);
+    empty = list_empty(&d->arch.hvm_domain.ioreq_server.list);
+    spin_unlock_recursive(&d->arch.hvm_domain.ioreq_server.lock);
+
+    return !empty;
+}
+
 int hvm_get_ioreq_server_info(struct domain *d, ioservid_t id,
                               unsigned long *ioreq_pfn,
                               unsigned long *bufioreq_pfn,
diff --git a/xen/drivers/passthrough/io.c b/xen/drivers/passthrough/io.c
index edd8dbd..1e5e365 100644
--- a/xen/drivers/passthrough/io.c
+++ b/xen/drivers/passthrough/io.c
@@ -24,6 +24,7 @@
 #include <asm/hvm/irq.h>
 #include <asm/hvm/support.h>
 #include <xen/hvm/irq.h>
+#include <asm/hvm/ioreq.h>
 #include <asm/io_apic.h>
 
 static DEFINE_PER_CPU(struct list_head, dpci_list);
@@ -384,7 +385,8 @@ int pt_irq_create_bind(
             pirq_dpci->dom = d;
             /* bind after hvm_irq_dpci is setup to avoid race with irq 
handler*/
             rc = pirq_guest_bind(d->vcpu[0], info, 0);
-            if ( rc == 0 && pt_irq_bind->u.msi.gtable )
+            if ( rc == 0 && pt_irq_bind->u.msi.gtable &&
+                 hvm_has_ioreq_server(d) )
             {
                 rc = msixtbl_pt_register(d, info, pt_irq_bind->u.msi.gtable);
                 if ( unlikely(rc) )
diff --git a/xen/include/asm-x86/hvm/ioreq.h b/xen/include/asm-x86/hvm/ioreq.h
index fbf2c74..6456cd2 100644
--- a/xen/include/asm-x86/hvm/ioreq.h
+++ b/xen/include/asm-x86/hvm/ioreq.h
@@ -31,6 +31,7 @@ int hvm_get_ioreq_server_info(struct domain *d, ioservid_t id,
                               unsigned long *ioreq_pfn,
                               unsigned long *bufioreq_pfn,
                               evtchn_port_t *bufioreq_port);
+int hvm_has_ioreq_server(struct domain *d);
 int hvm_map_io_range_to_ioreq_server(struct domain *d, ioservid_t id,
                                      uint32_t type, uint64_t start,
                                      uint64_t end);
-- 
2.7.4 (Apple Git-66)


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