2 files changed, 107 insertions, 6 deletions

diff --git a/src/arch/sparc/faults.cc b/src/arch/sparc/faults.cc
index 27a928f48..e2ff87726 100644
--- a/src/arch/sparc/faults.cc
+++ b/src/arch/sparc/faults.cc
@@ -628,9 +628,43 @@ FastInstructionAccessMMUMiss::invoke(ThreadContext *tc,
     if (!success) {
         panic("Tried to execute unmapped address %#x.\n", vaddr);
     } else {
-        Addr alignedVaddr = p->pTable->pageAlign(vaddr);
-        tc->getITBPtr()->insert(alignedVaddr, 0 /*partition id*/,
-                p->_pid /*context id*/, false, entry.pte);
+        Addr alignedvaddr = p->pTable->pageAlign(vaddr);
+
+        // Grab fields used during instruction translation to figure out
+        // which context to use.
+        uint64_t tlbdata = tc->readMiscRegNoEffect(MISCREG_TLB_DATA);
+
+        // Inside a VM, a real address is the address that guest OS would
+        // interpret to be a physical address. To map to the physical address,
+        // it still needs to undergo a translation. The instruction
+        // translation code in the SPARC ITLB code assumes that the context is
+        // zero (kernel-level) if real addressing is being used.
+        bool is_real_address = !bits(tlbdata, 4);
+
+        // The SPARC ITLB code assumes that traps are executed in context
+        // zero so we carry that assumption through here.
+        bool trapped = bits(tlbdata, 18, 16) > 0;
+
+        // The primary context acts as a PASID. It allows the MMU to
+        // distinguish between virtual addresses that would alias to the
+        // same physical address (if two or more processes shared the same
+        // virtual address mapping).
+        int primary_context = bits(tlbdata, 47, 32);
+
+        // The partition id distinguishes between virtualized environments.
+        int const partition_id = 0;
+
+        // Given the assumptions in the translateInst code in the SPARC ITLB,
+        // the logic works out to the following for the context.
+        int context_id = (is_real_address || trapped) ? 0 : primary_context;
+
+        // Insert the TLB entry.
+        // The entry specifying whether the address is "real" is set to
+        // false for syscall emulation mode regardless of whether the
+        // address is real in preceding code. Not sure sure that this is
+        // correct, but also not sure if it matters at all.
+        tc->getITBPtr()->insert(alignedvaddr, partition_id, context_id,
+                                false, entry.pte);
     }
 }
 
@@ -652,9 +686,73 @@ FastDataAccessMMUMiss::invoke(ThreadContext *tc, const StaticInstPtr &inst)
     if (!success) {
         panic("Tried to access unmapped address %#x.\n", vaddr);
     } else {
-        Addr alignedVaddr = p->pTable->pageAlign(vaddr);
-        tc->getDTBPtr()->insert(alignedVaddr, 0 /*partition id*/,
-                p->_pid /*context id*/, false, entry.pte);
+        Addr alignedvaddr = p->pTable->pageAlign(vaddr);
+
+        // Grab fields used during data translation to figure out
+        // which context to use.
+        uint64_t tlbdata = tc->readMiscRegNoEffect(MISCREG_TLB_DATA);
+
+        // The primary context acts as a PASID. It allows the MMU to
+        // distinguish between virtual addresses that would alias to the
+        // same physical address (if two or more processes shared the same
+        // virtual address mapping). There's a secondary context used in the
+        // DTLB translation code, but it should __probably__ be zero for
+        // syscall emulation code. (The secondary context is used by Solaris
+        // to allow kernel privilege code to access user space code:
+        // [ISBN 0-13-022496-0]:PG199.)
+        int primary_context = bits(tlbdata, 47, 32);
+
+        // "Hyper-Privileged Mode" is in use. There are three main modes of
+        // operation for Sparc: Hyper-Privileged Mode, Privileged Mode, and
+        // User Mode.
+        int hpriv = bits(tlbdata, 0);
+
+        // Reset, Error and Debug state is in use. Something horrible has
+        // happened or the system is operating in Reset Mode.
+        int red = bits(tlbdata, 1);
+
+        // Inside a VM, a real address is the address that guest OS would
+        // interpret to be a physical address. To map to the physical address,
+        // it still needs to undergo a translation. The instruction
+        // translation code in the SPARC ITLB code assumes that the context is
+        // zero (kernel-level) if real addressing is being used.
+        int is_real_address = !bits(tlbdata, 5);
+
+        // Grab the address space identifier register from the thread context.
+        // XXX: Inspecting how setMiscReg and setMiscRegNoEffect behave for
+        // MISCREG_ASI causes me to think that the ASI register implementation
+        // might be bugged. The NoEffect variant changes the ASI register
+        // value in the architectural state while the normal variant changes
+        // the context field in the thread context's currently decoded request
+        // but does not directly affect the ASI register value in the
+        // architectural state. The ASI values and the context field in the
+        // request packet seem to have completely different uses.
+        MiscReg reg_asi = tc->readMiscRegNoEffect(MISCREG_ASI);
+        ASI asi = static_cast<ASI>(reg_asi);
+
+        // The SPARC DTLB code assumes that traps are executed in context
+        // zero if the asi value is ASI_IMPLICIT (which is 0x0). There's also
+        // an assumption that the nucleus address space is being used, but
+        // the context is the relevant issue since we need to pass it to TLB.
+        bool trapped = bits(tlbdata, 18, 16) > 0;
+
+        // Given the assumptions in the translateData code in the SPARC DTLB,
+        // the logic works out to the following for the context.
+        int context_id = ((!hpriv && !red && is_real_address) ||
+                          asiIsReal(asi) ||
+                          (trapped && asi == ASI_IMPLICIT))
+                         ? 0 : primary_context;
+
+        // The partition id distinguishes between virtualized environments.
+        int const partition_id = 0;
+
+        // Insert the TLB entry.
+        // The entry specifying whether the address is "real" is set to
+        // false for syscall emulation mode regardless of whether the
+        // address is real in preceding code. Not sure sure that this is
+        // correct, but also not sure if it matters at all.
+        tc->getDTBPtr()->insert(alignedvaddr, partition_id, context_id,
+                                false, entry.pte);
     }
 }
 
diff --git a/src/arch/sparc/process.cc b/src/arch/sparc/process.cc
index c14680a6a..75c2529ef 100644
--- a/src/arch/sparc/process.cc
+++ b/src/arch/sparc/process.cc
@@ -149,6 +149,9 @@ SparcLiveProcess::initState()
     // Set the ASI register to something fixed
     tc->setMiscReg(MISCREG_ASI, ASI_PRIMARY);
 
+    // Set the MMU Primary Context Register to hold the process' pid
+    tc->setMiscReg(MISCREG_MMU_P_CONTEXT, _pid);
+
     /*
      * T1 specific registers
      */