[Xen-devel] [PATCH v12 03/12] x86/physdev: enable PHYSDEVOP_pci_mmcfg_reserved for PVH Dom0

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

So that MMCFG regions not present in the MCFG ACPI table can be added
at run time by the hardware domain.

Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
Reviewed-by: Paul Durrant <paul.durrant@xxxxxxxxxx>
---
Cc: Jan Beulich <jbeulich@xxxxxxxx>
Cc: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
Cc: Paul Durrant <paul.durrant@xxxxxxxxxx>
---
Changes since v7:
 - Add newline in hvm_physdev_op for non-fallthrough case.

Changes since v6:
 - Do not return EEXIST if the same exact region is already tracked by
   Xen.

Changes since v5:
 - Check for has_vpci before calling register_vpci_mmcfg_handler
   instead of checking for is_hvm_domain.

Changes since v4:
 - Change the hardware_domain check in hvm_physdev_op to a vpci check.
 - Only register the MMCFG area, but don't scan it.

Changes since v3:
 - New in this version.
---
 xen/arch/x86/hvm/hypercall.c |  5 +++++
 xen/arch/x86/hvm/io.c        | 16 +++++++++++-----
 xen/arch/x86/physdev.c       | 11 +++++++++++
 3 files changed, 27 insertions(+), 5 deletions(-)

diff --git a/xen/arch/x86/hvm/hypercall.c b/xen/arch/x86/hvm/hypercall.c
index 5742dd1797..85eacd7d33 100644
--- a/xen/arch/x86/hvm/hypercall.c
+++ b/xen/arch/x86/hvm/hypercall.c
@@ -89,6 +89,11 @@ static long hvm_physdev_op(int cmd, 
XEN_GUEST_HANDLE_PARAM(void) arg)
         if ( !has_pirq(curr->domain) )
             return -ENOSYS;
         break;
+
+    case PHYSDEVOP_pci_mmcfg_reserved:
+        if ( !has_vpci(curr->domain) )
+            return -ENOSYS;
+        break;
     }
 
     if ( !curr->hcall_compat )
diff --git a/xen/arch/x86/hvm/io.c b/xen/arch/x86/hvm/io.c
index 04425c064b..556810c126 100644
--- a/xen/arch/x86/hvm/io.c
+++ b/xen/arch/x86/hvm/io.c
@@ -507,10 +507,9 @@ static const struct hvm_mmio_ops vpci_mmcfg_ops = {
     .write = vpci_mmcfg_write,
 };
 
-int __hwdom_init register_vpci_mmcfg_handler(struct domain *d, paddr_t addr,
-                                             unsigned int start_bus,
-                                             unsigned int end_bus,
-                                             unsigned int seg)
+int register_vpci_mmcfg_handler(struct domain *d, paddr_t addr,
+                                unsigned int start_bus, unsigned int end_bus,
+                                unsigned int seg)
 {
     struct hvm_mmcfg *mmcfg, *new = xmalloc(struct hvm_mmcfg);
 
@@ -535,9 +534,16 @@ int __hwdom_init register_vpci_mmcfg_handler(struct domain 
*d, paddr_t addr,
         if ( new->addr < mmcfg->addr + mmcfg->size &&
              mmcfg->addr < new->addr + new->size )
         {
+            int ret = -EEXIST;
+
+            if ( new->addr == mmcfg->addr &&
+                 new->start_bus == mmcfg->start_bus &&
+                 new->segment == mmcfg->segment &&
+                 new->size == mmcfg->size )
+                ret = 0;
             write_unlock(&d->arch.hvm_domain.mmcfg_lock);
             xfree(new);
-            return -EEXIST;
+            return ret;
         }
 
     if ( list_empty(&d->arch.hvm_domain.mmcfg_regions) )
diff --git a/xen/arch/x86/physdev.c b/xen/arch/x86/physdev.c
index 380d36f6b9..984491c3dc 100644
--- a/xen/arch/x86/physdev.c
+++ b/xen/arch/x86/physdev.c
@@ -557,6 +557,17 @@ ret_t do_physdev_op(int cmd, XEN_GUEST_HANDLE_PARAM(void) 
arg)
 
         ret = pci_mmcfg_reserved(info.address, info.segment,
                                  info.start_bus, info.end_bus, info.flags);
+        if ( !ret && has_vpci(currd) )
+        {
+            /*
+             * For HVM (PVH) domains try to add the newly found MMCFG to the
+             * domain.
+             */
+            ret = register_vpci_mmcfg_handler(currd, info.address,
+                                              info.start_bus, info.end_bus,
+                                              info.segment);
+        }
+
         break;
     }
 
-- 
2.16.2


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