x86: Segment initialization to support KvmCPU in SE

This patch sets up low and high privilege code and data segments and places them
in the following order: cs low, ds low, ds, cs, in the GDT. Additionally, a
syscall and page fault handler for KvmCPU in SE mode are defined. The order of
the segment selectors in GDT is required in this manner for interrupt handling
to work properly. Segment initialization is done for all the thread
contexts.

1 files changed, 58 insertions, 0 deletions

diff --git a/src/arch/x86/regs/misc.hh b/src/arch/x86/regs/misc.hh
index 5887e7486..77f4e1bcd 100644
--- a/src/arch/x86/regs/misc.hh
+++ b/src/arch/x86/regs/misc.hh
@@ -613,6 +613,9 @@ namespace X86ISA
     EndBitUnion(CR3)
 
     BitUnion64(CR4)
+        Bitfield<18> osxsave; // Enable XSAVE and Proc Extended States
+        Bitfield<16> fsgsbase; // Enable RDFSBASE, RDGSBASE, WRFSBASE,
+                               // WRGSBASE instructions
         Bitfield<10> osxmmexcpt; // Operating System Unmasked
                                  // Exception Support
         Bitfield<9> osfxsr; // Operating System FXSave/FSRSTOR Support
@@ -885,6 +888,44 @@ namespace X86ISA
         EndSubBitUnion(type)
     EndBitUnion(SegDescriptor)
 
+    /**
+     * TSS Descriptor (long mode - 128 bits)
+     * the lower 64 bits
+     */
+    BitUnion64(TSSlow)
+        Bitfield<63, 56> baseHigh;
+        Bitfield<39, 16> baseLow;
+        Bitfield<55> g; // Granularity
+        Bitfield<52> avl; // Available To Software
+        Bitfield<51, 48> limitHigh;
+        Bitfield<15, 0> limitLow;
+        Bitfield<47> p; // Present
+        Bitfield<46, 45> dpl; // Descriptor Privilege-Level
+        SubBitUnion(type, 43, 40)
+            // Specifies whether this descriptor is for code or data.
+            Bitfield<43> codeOrData;
+
+            // These bit fields are for code segments
+            Bitfield<42> c; // Conforming
+            Bitfield<41> r; // Readable
+
+            // These bit fields are for data segments
+            Bitfield<42> e; // Expand-Down
+            Bitfield<41> w; // Writable
+
+            // This is used for both code and data segments.
+            Bitfield<40> a; // Accessed
+        EndSubBitUnion(type)
+    EndBitUnion(TSSlow)
+
+    /**
+     * TSS Descriptor (long mode - 128 bits)
+     * the upper 64 bits
+     */
+    BitUnion64(TSShigh)
+        Bitfield<31, 0> base;
+    EndBitUnion(TSShigh)
+
     BitUnion64(SegAttr)
         Bitfield<1, 0> dpl;
         Bitfield<2> unusable;
@@ -911,6 +952,23 @@ namespace X86ISA
     EndBitUnion(GateDescriptor)
 
     /**
+     * Long Mode Gate Descriptor
+     */
+    BitUnion64(GateDescriptorLow)
+        Bitfield<63, 48> offsetHigh; // Target Code-Segment Offset
+        Bitfield<47> p; // Present
+        Bitfield<46, 45> dpl; // Descriptor Privilege-Level
+        Bitfield<43, 40> type;
+        Bitfield<35, 32> IST; // IST pointer to TSS -- new stack for exception handling
+        Bitfield<31, 16> selector; // Target Code-Segment Selector
+        Bitfield<15, 0> offsetLow; // Target Code-Segment Offset
+    EndBitUnion(GateDescriptorLow)
+
+    BitUnion64(GateDescriptorHigh)
+        Bitfield<31, 0> offset; // Target Code-Segment Offset
+    EndBitUnion(GateDescriptorHigh)
+
+    /**
      * Descriptor-Table Registers
      */
     BitUnion64(GDTR)