Changeset 21942 in vbox for trunk/src/VBox/VMM

Timestamp:

Aug 3, 2009 2:39:00 PM (16 years ago)

Author:

vboxsync

svn:sync-xref-src-repo-rev:

50627

Message:

VMM: detect syscall usage on the host.

Location:

trunk/src/VBox/VMM

Files:

• VMMR0/CPUMR0.cpp (modified) (2 diffs)
• VMMSwitcher.cpp (modified) (2 diffs)
• VMMSwitcher/PAEand32Bit.mac (modified) (5 diffs)

trunk/src/VBox/VMM/VMMR0/CPUMR0.cpp

@@ -61 +61 @@
 
     /*
-     * Check for sysenter if it's used.
+     * Check for sysenter and syscall usage.
      */
     if (ASMHasCpuId())
     {
+        /*
+         * SYSENTER/SYSEXIT
+         *
+         * Intel docs claim you should test both the flag and family, model &
+         * stepping because some Pentium Pro CPUs have the SEP cpuid flag set,
+         * but don't support it.  AMD CPUs may support this feature in legacy
+         * mode, they've banned it from long mode.  Since we switch to 32-bit
+         * mode when entering raw-mode context the feature would become
+         * accessible again on AMD CPUs, so we have to check regardless of
+         * host bitness.
+         */
         uint32_t u32CpuVersion;
         uint32_t u32Dummy;
-        uint32_t u32Features;
-        ASMCpuId(1, &u32CpuVersion, &u32Dummy, &u32Dummy, &u32Features);
+        uint32_t fFeatures;
+        ASMCpuId(1, &u32CpuVersion, &u32Dummy, &u32Dummy, &fFeatures);
         uint32_t u32Family   = u32CpuVersion >> 8;
         uint32_t u32Model    = (u32CpuVersion >> 4) & 0xF;
         uint32_t u32Stepping = u32CpuVersion & 0xF;
-
-        /*
-         * Intel docs claim you should test both the flag and family, model & stepping.
-         * Some Pentium Pro cpus have the SEP cpuid flag set, but don't support it.
-         */
-        if (    (u32Features & X86_CPUID_FEATURE_EDX_SEP)
-            && !(u32Family == 6 && u32Model < 3 && u32Stepping < 3))
+        if (    (fFeatures & X86_CPUID_FEATURE_EDX_SEP)
+            &&  (   u32Family   != 6    /* (> pentium pro) */
+                 || u32Model    >= 3
+                 || u32Stepping >= 3
+                 || !ASMIsIntelCpu())
+           )
         {
             /*
@@ -91 +101 @@
         }
 
-        /** @todo check for AMD and syscall!!!!!! */
+        /*
+         * SYSCALL/SYSRET
+         *
+         * This feature is indicated by the SEP bit returned in EDX by CPUID
+         * function 0x80000001.  Intel CPUs only supports this feature in
+         * long mode.  Since we're not running 64-bit guests in raw-mode there
+         * are no issues with 32-bit intel hosts.
+         */
+        uint32_t cExt = 0;
+        ASMCpuId(0x80000000, &cExt, &u32Dummy, &u32Dummy, &u32Dummy);
+        if (    cExt >= 0x80000001
+            &&  cExt <= 0x8000ffff)
+        {
+            uint32_t fExtFeaturesEDX = ASMCpuId_EDX(0x80000001);
+            if (fExtFeaturesEDX & X86_CPUID_AMD_FEATURE_EDX_SEP)
+            {
+#ifdef RT_ARCH_X86
+# ifdef VBOX_WITH_HYBRID_32BIT_KERNEL
+                if (fExtFeaturesEDX & X86_CPUID_AMD_FEATURE_EDX_LONG_MODE)
+# else
+                if (!ASMIsIntelCpu())
+# endif
+#endif
+                {
+                    uint64_t fEfer = ASMRdMsr(MSR_K6_EFER);
+                    if (fEfer & MSR_K6_EFER_SCE)
+                    {
+                        pVM->cpum.s.fHostUseFlags |= CPUM_USE_SYSCALL;
+                        Log(("CPUMR0Init: host uses syscall\n"));
+                    }
+                }
+            }
+        }
     }
 

trunk/src/VBox/VMM/VMMSwitcher.cpp

@@ -558 +558 @@
 
             /*
-             * Insert relative jump to specified target it SYSENTER isn't used by the host.
+             * Insert relative jump to specified target it SYSCALL isn't used by the host.
              */
             case FIX_NO_SYSCALL_JMP:
@@ -564 +564 @@
                 uint32_t offTrg = *u.pu32++;
                 Assert(offTrg < pSwitcher->cbCode);
-                if (!CPUMIsHostUsingSysEnter(pVM))
+                if (!CPUMIsHostUsingSysCall(pVM))
                 {
                     *uSrc.pu8++ = 0xe9; /* jmp rel32 */

trunk/src/VBox/VMM/VMMSwitcher/PAEand32Bit.mac

@@ -157 +157 @@
 htg_no_sysenter:
 
+    FIXUP FIX_NO_SYSCALL_JMP, 0, htg_no_syscall - NAME(Start) ; this will insert a jmp htg_no_syscall if host doesn't use syscall.
+    ; clear MSR_K6_EFER_SCE.
+    mov     ebx, edx                    ; save edx
+    mov     ecx, MSR_K6_EFER
+    rdmsr                               ; edx:eax <- MSR[ecx]
+    and     eax, ~MSR_K6_EFER_SCE
+    wrmsr
+    mov     edx, ebx                    ; restore edx
+    jmp short htg_no_syscall
+
+ALIGNCODE(16)
+htg_no_syscall:
+
     ;; handle use flags.
     mov     esi, [edx + CPUMCPU.fUseFlags] ; esi == use flags.
@@ -216 +229 @@
     ; Store the hypervisor cr3 for later loading
     mov     ebp, [edx + CPUMCPU.Hyper.cr3]
-    
+
     ;;
     ;; Load Intermediate memory context.
@@ -381 +394 @@
     ; callees expect CPUM ptr
     CPUM_FROM_CPUMCPU(edx)
-    
+
 %ifdef VBOX_WITH_STATISTICS
     FIXUP FIX_GC_VM_OFF, 1, VM.StatSwitcherToGC
@@ -420 +433 @@
     mov     eax, dr3
     mov     [edx + CPUMCPU.Host.dr3], eax
-    
+
     ; load hyper DR0-7
     mov     ebx, [edx + CPUMCPU.Hyper.dr]
@@ -864 +877 @@
 gth_sysenter_no:
 
-    ;; @todo AMD syscall
+    FIXUP FIX_NO_SYSCALL_JMP, 0, gth_syscall_no - NAME(Start) ; this will insert a jmp gth_syscall_no if host doesn't use syscall.
+    ; set MSR_K6_EFER_SCE.
+    mov     ebx, edx                    ; save edx
+    mov     ecx, MSR_K6_EFER
+    rdmsr
+    or      eax, MSR_K6_EFER_SCE
+    wrmsr
+    mov     edx, ebx                    ; restore edx
+    jmp short gth_syscall_no
+
+ALIGNCODE(16)
+gth_syscall_no:
 
     ; Restore FPU if guest has used it.