From: Peter Dinda <pdinda@northwestern.edu>
Date: Wed, 25 Mar 2009 18:39:28 +0000 (-0500)
Subject: First attempt at speculative paging around the address that faulted
X-Git-Url: http://v3vee.org/palacios/gitweb/gitweb.cgi?p=palacios.git;a=commitdiff_plain;h=9487b7d59cab801ef521a89187dfd1e33fa36c45

First attempt at speculative paging around the address that faulted
It only attempts to fill the leaf page table
---

diff --git a/geekos/src/geekos/main.c b/geekos/src/geekos/main.c
index 5d71341..310fcf9 100644
--- a/geekos/src/geekos/main.c
+++ b/geekos/src/geekos/main.c
@@ -241,7 +241,7 @@ void Main(struct Boot_Info* bootInfo)
 #endif
 
 
-#if 1
+#if 0
   struct Kernel_Thread *spin_thread;
 
   spin_thread=Start_Kernel_Thread(Spin,0,PRIORITY_NORMAL,false);
diff --git a/manual/manual.pdf b/manual/manual.pdf
index 887fd33..78e5043 100644
Binary files a/manual/manual.pdf and b/manual/manual.pdf differ
diff --git a/palacios/src/palacios/vmm_shadow_paging.c b/palacios/src/palacios/vmm_shadow_paging.c
index 8074c16..91004f9 100644
--- a/palacios/src/palacios/vmm_shadow_paging.c
+++ b/palacios/src/palacios/vmm_shadow_paging.c
@@ -30,6 +30,14 @@
 
 #include <palacios/vmm_direct_paging.h>
 
+
+// set this to 1 if you want us to attempt to
+// fetch multiple entries on a page fault
+#define SPECULATIVE_PAGING 1
+
+#define REGULAR_PAGE_FAULT 0
+#define SPECULATIVE_PAGE_FAULT 1
+
 #ifndef DEBUG_SHADOW_PAGING
 #undef PrintDebug
 #define PrintDebug(fmt, args...)
@@ -126,6 +134,7 @@ int v3_activate_passthrough_pt(struct guest_info * info) {
 
 
 int v3_handle_shadow_pagefault(struct guest_info * info, addr_t fault_addr, pf_error_t error_code) {
+  int rc;
   
     if (v3_get_mem_mode(info) == PHYSICAL_MEM) {
 	// If paging is not turned on we need to handle the special cases
@@ -134,14 +143,38 @@ int v3_handle_shadow_pagefault(struct guest_info * info, addr_t fault_addr, pf_e
 
 	switch (v3_get_cpu_mode(info)) {
 	    case PROTECTED:
-		return handle_shadow_pagefault_32(info, fault_addr, error_code);
+	      return handle_shadow_pagefault_32(info, fault_addr, error_code);
 		break;
 	    case PROTECTED_PAE:
 		return handle_shadow_pagefault_32pae(info, fault_addr, error_code);
 	    case LONG:
 	    case LONG_32_COMPAT:
-	    case LONG_16_COMPAT:
-		return handle_shadow_pagefault_64(info, fault_addr, error_code);
+	case LONG_16_COMPAT: {
+	      addr_t curr_addr;
+	      addr_t fault_addr_base;
+	      // first, we will handle the actual fault, non-speculatively
+	      rc=handle_shadow_pagefault_64(info, fault_addr, error_code, REGULAR_PAGE_FAULT);
+	      if (rc) {
+		return -1;
+	      } 
+	      if (!SPECULATIVE_PAGING) { 
+		return 0;
+	      }
+	      fault_addr_base=PAGE_ADDR_4KB(fault_addr);
+	      PrintDebug("Attempting speculative paging around %p\n",(void*)fault_addr_base);
+	      for (curr_addr = (fault_addr_base & (~0x1fffffLL)) ; 
+		   curr_addr < (fault_addr_base | (0x1fffffLL)) ;
+		   curr_addr+=PAGE_SIZE) {
+		if (curr_addr!=fault_addr_base) { 
+		  rc=handle_shadow_pagefault_64(info, curr_addr, error_code, SPECULATIVE_PAGE_FAULT);
+		  if (rc) {
+		    PrintDebug("Speculative page fault handler failed at %p\n",(void*)curr_addr);
+		    return -1;
+		  } 
+		}
+	      }
+	      return 0;
+	    }
 		break;
 	    default:
 		PrintError("Unhandled CPU Mode: %s\n", v3_cpu_mode_to_str(v3_get_cpu_mode(info)));