Changeset 61144 in vbox for trunk/src/VBox/VMM/VMMRZ

Timestamp:

May 23, 2016 10:16:26 PM (9 years ago)

Author:

vboxsync

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

107425

Message:

CPUM,HM,GVMM,TRPM,VMM: Next part of the FPU state handling for IEM. This is a little bit risky change as we now leave CR0.TS+EM cleared after saving the host state, they only get restored when we restore the host state. On Windows, Darwin, and later on Linux (needs testing) we will rely on #NM handling of the host OS and not our own CR.TS/EM handy work. This means we won't be saving the host state but rather the ring-3 state of our own thread. This change also introduces a CPUM force flag that we're using for restoring CR0.TS/EM in raw-mode (it may be extended with other uses later if we need to).

Location:

trunk/src/VBox/VMM/VMMRZ

Files:

• CPUMRZ.cpp (modified) (7 diffs)
• CPUMRZA.asm (modified) (8 diffs)

trunk/src/VBox/VMM/VMMRZ/CPUMRZ.cpp

@@ -50 +50 @@
         case 0:
             cpumRZSaveHostFPUState(&pVCpu->cpum.s);
+#ifdef IN_RC
+            VMCPU_FF_SET(pVCpu, VMCPU_FF_CPUM); /* Must recalc CR0 before executing more code! */
+#endif
             break;
 
@@ -57 +60 @@
             {
                 pVCpu->cpum.s.fUseFlags &= ~CPUM_SYNC_FPU_STATE;
-/** @todo tell HM! */
+                HMR0NotifyCpumUnloadedGuestFpuState(pVCpu);
             }
 #endif
@@ -63 +66 @@
 
         case CPUM_USED_FPU_GUEST | CPUM_USED_FPU_HOST:
-/** @todo tell HM! */
 #if defined(IN_RING0) && ARCH_BITS == 32 && defined(VBOX_WITH_64_BITS_GUESTS)
             Assert(!(pVCpu->cpum.s.fUseFlags & CPUM_SYNC_FPU_STATE));
@@ -70 +72 @@
             else
 #endif
-                cpumRZSaveGuestFpuState(&pVCpu->cpum.s);
-
+                cpumRZSaveGuestFpuState(&pVCpu->cpum.s, true /*fLeaveFpuAccessible*/);
+#ifdef IN_RING0
+            HMR0NotifyCpumUnloadedGuestFpuState(pVCpu);
+#endif
             break;
 
@@ -112 +116 @@
         else
 #endif
-            cpumRZSaveGuestFpuState(&pVCpu->cpum.s);
+            cpumRZSaveGuestFpuState(&pVCpu->cpum.s, false /*fLeaveFpuAccessible*/);
         pVCpu->cpum.s.fUseFlags |= CPUM_USED_FPU_GUEST;
     }
@@ -129 +133 @@
 #if defined(VBOX_WITH_KERNEL_USING_XMM) && HC_ARCH_BITS == 64
     NOREF(pVCpu);
+#error "do NOT commit this"
 #else
     if (pVCpu->cpum.s.fUseFlags & CPUM_USED_FPU_GUEST)
@@ -141 +146 @@
         else
 # endif
+        {
+RTLogPrintf("calling cpumRZSaveGuestSseRegisters\n");
             cpumRZSaveGuestSseRegisters(&pVCpu->cpum.s);
+        }
     }
 #endif

trunk/src/VBox/VMM/VMMRZ/CPUMRZA.asm

@@ -34 +34 @@
 ; Saves the host FPU/SSE/AVX state.
 ;
+; Will return with CR0.EM and CR0.TS cleared!  This is the normal state in
+; ring-0, whereas in raw-mode the caller will probably set VMCPU_FF_CPUM to
+; re-evaluate the situation before executing more guest code.
+;
 ; @returns  VINF_SUCCESS (0) in EAX
 ; @param    pCpumCpu  x86:[ebp+8] gcc:rdi msc:rcx     CPUMCPU pointer
@@ -66 +70 @@
         pushf                           ; The darwin kernel can get upset or upset things if an
         cli                             ; interrupt occurs while we're doing fxsave/fxrstor/cr0.
-%ifdef VBOX_WITH_KERNEL_USING_XMM
+
+%ifndef CPUM_CAN_USE_FPU_IN_R0
+        ;
+        ; In raw-mode context and on systems where the kernel doesn't necessarily
+        ; allow us to use the FPU in ring-0 context, we have to disable FPU traps
+        ; before doing fxsave/xsave here.  (xCX is 0 if no CR0 was necessary.)  We
+        ; leave it like that so IEM can use the FPU/SSE/AVX host CPU features directly.
+        ;
+        SAVE_CR0_CLEAR_FPU_TRAPS xCX, xAX
+        ;; @todo What about XCR0?
  %ifdef IN_RING0
-        movaps  xmm0, xmm0              ; Make 100% sure it's used before we save it or mess with CR0/XCR0.
- %endif
-%endif
-        SAVE_CR0_CLEAR_FPU_TRAPS xCX, xAX ; xCX is now old CR0 value, don't use!
-
+        mov     [pCpumCpu + CPUMCPU.Host.cr0Fpu], xCX
+ %else
+  %error "Huh?"
+ %endif
+%endif
+        ;
+        ; Save the host state (xsave/fxsave will cause thread FPU state to be
+        ; loaded on systems where we are allowed to use it in ring-0.
+        ;
         CPUMR0_SAVE_HOST
-        ;; @todo Save CR0 + XCR0 bits related to FPU, SSE and AVX*, leaving these register sets accessible to IEM.
-
-        RESTORE_CR0 xCX
+
         or      dword [pCpumCpu + CPUMCPU.fUseFlags], (CPUM_USED_FPU_HOST | CPUM_USED_FPU_SINCE_REM) ; Latter is not necessarily true, but normally yes.
         popf
@@ -95 +110 @@
 ;
 ; @param    pCpumCpu  x86:[ebp+8] gcc:rdi msc:rcx     CPUMCPU pointer
+; @param    fLeaveFpuAccessible  x86:[ebp+c] gcc:sil msc:dl      Whether to restore CR0 and XCR0 on
+;                                                                the way out. Only really applicable to RC.
 ;
 align 16
@@ -124 +141 @@
         pushf                           ; The darwin kernel can get upset or upset things if an
         cli                             ; interrupt occurs while we're doing fxsave/fxrstor/cr0.
-        SAVE_CR0_CLEAR_FPU_TRAPS xCX, xAX ; xCX is now old CR0 value, don't use!
-
+
+ %ifdef IN_RC
+        SAVE_CR0_CLEAR_FPU_TRAPS xCX, xAX ; xCX must be preserved until CR0 is restored!
+ %endif
 
  %ifndef VBOX_WITH_KERNEL_USING_XMM
@@ -185 +204 @@
  %endif
 
+        and     dword [pCpumCpu + CPUMCPU.fUseFlags], ~CPUM_USED_FPU_GUEST
+ %ifdef IN_RC
+        test    byte [ebp + 0ch], 1     ; fLeaveFpuAccessible
+        jz      .no_cr0_restore
         RESTORE_CR0 xCX
-        and     dword [pCpumCpu + CPUMCPU.fUseFlags], ~CPUM_USED_FPU_GUEST
-
+.no_cr0_restore:
+ %endif
         popf
 %ifdef RT_ARCH_X86
@@ -202 +225 @@
 ;;
 ; Saves the guest XMM0..15 registers.
+;
+; The purpose is to actualize the register state for read-only use, so CR0 is
+; restored in raw-mode context (so, the FPU/SSE/AVX CPU features can be
+; inaccessible upon return).
 ;
 ; @param    pCpumCpu  x86:[ebp+8] gcc:rdi msc:rcx     CPUMCPU pointer
@@ -228 +255 @@
  %else
   %error "Invalid context!"
+ %endif
+
+ %ifdef IN_RC
+        ; Temporarily grant access to the SSE state. xDX must be preserved until CR0 is restored!
+        SAVE_CR0_CLEAR_FPU_TRAPS xDX, xAX
  %endif
 
@@ -251 +283 @@
         movdqa  [xCX + X86FXSTATE.xmm15], xmm15
  %endif
+
+ %ifdef IN_RC
+        RESTORE_CR0 xDX                 ; Restore CR0 if we changed it above.
+ %endif
+
 %endif ; !VBOX_WITH_KERNEL_USING_XMM