Add a XEN_API to get the maximum physical RAM address

The initialization code in XEN.DLL already scans the physical memory
ranges so it's trivial to store the maximum physical address seen and then
provide a function to return that value.

Signed-off-by: Paul Durrant <paul.durrant@citrix.com>

diff --git a/include/xen.h b/include/xen.h
index 98b0748324fea1e68e677654527081d371054a70..edfadc9c240cd207e9ac1d83f1a1a6bb739dd252 100644 (file)
--- a/include/xen.h
+++ b/include/xen.h
@@ -452,4 +452,10 @@ SystemVirtualCpuIndex(
     OUT unsigned int    *vcpu_id
     );
 
+XEN_API
+PHYSICAL_ADDRESS
+SystemMaximumPhysicalAddress(
+    VOID
+    );
+
 #endif  // _XEN_H

diff --git a/src/xen/system.c b/src/xen/system.c
index dbf708d0f87d1239d7db1d050b60cccd8f6d53ef..a7b46d131382afd527ae1d8a664920c795ee356b 100644 (file)
--- a/src/xen/system.c
+++ b/src/xen/system.c
@@ -62,6 +62,7 @@ typedef struct _SYSTEM_CONTEXT {
     ULONG               ProcessorCount;
     PVOID               PowerStateHandle;
     PVOID               ProcessorChangeHandle;
+    PHYSICAL_ADDRESS    MaximumPhysicalAddress;
 } SYSTEM_CONTEXT, *PSYSTEM_CONTEXT;
 
 static SYSTEM_CONTEXT   SystemContext;
@@ -224,6 +225,7 @@ SystemGetMemoryInformation(
     VOID
     )
 {
+    PSYSTEM_CONTEXT         Context = &SystemContext;
     PHYSICAL_MEMORY_RANGE   *Range;
     ULONG                   Index;
     NTSTATUS                status;
@@ -247,10 +249,17 @@ SystemGetMemoryInformation(
              Index,
              Start.HighPart, Start.LowPart,
              End.HighPart, End.LowPart);
+
+        if (End.QuadPart > Context->MaximumPhysicalAddress.QuadPart)
+            Context->MaximumPhysicalAddress.QuadPart = End.QuadPart;
     }
 
     ExFreePool(Range);
 
+    Info("MaximumPhysicalAddress = %08x.%08x\n",
+         Context->MaximumPhysicalAddress.HighPart,
+         Context->MaximumPhysicalAddress.LowPart);
+
     return STATUS_SUCCESS;
 
 fail1:
@@ -1018,6 +1027,17 @@ fail1:
     return status;
 }
 
+XEN_API
+PHYSICAL_ADDRESS
+SystemMaximumPhysicalAddress(
+    VOID
+    )
+{
+    PSYSTEM_CONTEXT Context = &SystemContext;
+
+    return Context->MaximumPhysicalAddress;
+}
+
 VOID
 SystemTeardown(
     VOID
@@ -1032,6 +1052,8 @@ SystemTeardown(
     __SystemFree(Context->Madt);
     Context->Madt = NULL;
 
+    Context->MaximumPhysicalAddress.QuadPart = 0;
+
     (VOID) InterlockedDecrement(&Context->References);
 
     ASSERT(IsZeroMemory(Context, sizeof (SYSTEM_CONTEXT)));